5.56 versus .223 pressures - 12/01/19
I have three rifles chambered in 5.56 NATO. Why can’t I reload .223 casings to the same pressures and velocity.? I would like to be getting around 3000 ft./s with 62 grain cup And core soft points.
Re: 5.56 versus .223 pressures - 12/01/19
They are the same.
https://www.luckygunner.com/labs/5-56-vs-223/?utm_source=Newsletter&utm_campaign=349674f69a-6%2F26%2F12-
https://www.luckygunner.com/labs/5-56-vs-223/?utm_source=Newsletter&utm_campaign=349674f69a-6%2F26%2F12-
Re: 5.56 versus .223 pressures - 12/01/19
The difference is in the chamber dimensions, not the brass. The primary difference is the 5.56 NATO chamber has a slightly longer throat to lower chamber pressure compared to the .223 chamber.
There should be no problem loading .223 stamped brass to 5.56 NATO pressure as long as you fire it in a 5.56 NATO chamber.
There should be no problem loading .223 stamped brass to 5.56 NATO pressure as long as you fire it in a 5.56 NATO chamber.
Re: 5.56 versus .223 pressures - 12/01/19
Originally Posted by Sasha_and_Abby
I have three rifles chambered in 5.56 NATO. Why can’t I reload .223 casings to the same pressures and velocity.? I would like to be getting around 3000 ft./s with 62 grain cup And core soft points.
You can and I do. I like benchmark for 50-60 grain bullets. I just load them up the usual way, till I see pressure signs. My 223 loads are well beyond book loads, probably 150 FPS faster than book loads.
Re: 5.56 versus .223 pressures - 12/01/19
Originally Posted by NVhntr
The difference is in the chamber dimensions, not the brass. The primary difference is the 5.56 NATO chamber has a slightly longer throat to lower chamber pressure compared to the .223 chamber.
There should be no problem loading .223 stamped brass to 5.56 NATO pressure as long as you fire it in a 5.56 NATO chamber.
There should be no problem loading .223 stamped brass to 5.56 NATO pressure as long as you fire it in a 5.56 NATO chamber.
true of the .308 and 7.52x51 too.
Re: 5.56 versus .223 pressures - 12/01/19
I have a Weatherby Vanguard2 in .223 caliber and a 5.56 AR. A friend of mine who usually knows what he is talking about told me that a bolt gun in .223 can handle my 5.56 loads without a problem. He says it is only with semi-auto that there might be an issue. Is this true?
Re: 5.56 versus .223 pressures - 12/01/19
Originally Posted by Sasha_and_Abby
I have three rifles chambered in 5.56 NATO. Why can’t I reload .223 casings to the same pressures and velocity.? I would like to be getting around 3000 ft./s with 62 grain cup And core soft points.
What rifles?
Re: 5.56 versus .223 pressures - 12/01/19
I've loaded untold thousands of .223 over the years,....shot them in AR's, TC Contenders, Ruger 77s, H&R Handi Rifles, Mini 14's, and probably some others that I've forgotten.
I make no distinction between .223 and 5.56.
Chamber and throat dimensions vary between manufacturers at least as much as they do between .223 and 5.56 industry standards.
I make no distinction between .223 and 5.56.
Chamber and throat dimensions vary between manufacturers at least as much as they do between .223 and 5.56 industry standards.
Re: 5.56 versus .223 pressures - 12/01/19
Bristoe is correct. I can mix and match with my bolt rifle and AR.
Re: 5.56 versus .223 pressures - 12/01/19
Millions of rounds are fired by millions of people every year without any sort of issue.
I've never really heard a valid issue from firing one in the other.
Then we throw in the .223 Wylde.... Just for grins.
I've never really heard a valid issue from firing one in the other.
Then we throw in the .223 Wylde.... Just for grins.
Re: 5.56 versus .223 pressures - 12/01/19
And if you worry about such things and can't decide there's the Wylde chambering.
"A .223 Wylde chamber is a hybrid rifle chamber designed to allow .22 caliber barrels to safely fire either .223 Remington or 5.56x45mm NATO ammunition. " wiki
"A .223 Wylde chamber is a hybrid rifle chamber designed to allow .22 caliber barrels to safely fire either .223 Remington or 5.56x45mm NATO ammunition. " wiki
Re: 5.56 versus .223 pressures - 12/01/19
And my CZ 527s all say both are fine. From the factory
Re: 5.56 versus .223 pressures - 12/01/19
AR's, Bolts, Mini14's T/C, doesn't seem to matter .223 or 5.56 factory or reloads, over 35 years now and I can't even recall a flattened primer, much less a real problem
I know I have read it does, but the in early '80s in a gunsmith class with several older fella's that had probably forgotten more about firearms than I know told me it really didn't matter, apparently they were correct.
I know I have read it does, but the in early '80s in a gunsmith class with several older fella's that had probably forgotten more about firearms than I know told me it really didn't matter, apparently they were correct.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by Hastings
I have a Weatherby Vanguard2 in .223 caliber and a 5.56 AR. A friend of mine who usually knows what he is talking about told me that a bolt gun in .223 can handle my 5.56 loads without a problem. He says it is only with semi-auto that there might be an issue. Is this true?
If you have a .223 chamber stick with .223 ammo. (55,000 psi) Like others have said, it's the chamber and not so much the ammo. No a bolt .223 may not be able to handle the pressure of a 5.56 (62,300 psi) and it just isn't about semi auto vs. bolt action. A bolt action can have a .223 or a 5.56 chamber just like a semi auto can have a .223 or a 5.56 chamber. Your buddy needs to re-think this.
kwg
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by steve4102
Originally Posted by Sasha_and_Abby
I have three rifles chambered in 5.56 NATO. Why can’t I reload .223 casings to the same pressures and velocity.? I would like to be getting around 3000 ft./s with 62 grain cup And core soft points.
What rifles?
Two AR's and Ruger American... the bolt gun is the one I want to load 5.56 pressure for.
Re: 5.56 versus .223 pressures - 12/02/19
The real question is, 62 kpsi by whose standard?
NATO 5.56 is nominally 62 kpsi, but the standard, which includes pressure measurement methods, is EPVAT. EPVAT pressure measurement is similar to that used in CIP (but not the same).
The US military does not adhere to the EPVAT standard, but rather employs the SCATP standard. SCATP prescribes the very same pressure measurement methods utilized by SAAMI. The highest pressures in any spec (and I mean actual US military documents) I have been able to locate are about 58,600 psi (IIRC).
I am not too concerned about .223 ammo being loaded to about 58000 psi (and I'm talking SAAMI, as we usually speak of pressures) , but I am not so sure I'd want to push any handloaded ammo much beyond 58000 psi.
Can .223 brass handle 62000 (SAAMI) psi repeatedly? Maybe, maybe not. Can it handle 62000 (CIP or EPVAT) psi? Evidently it can. But those pressure levels should translate to well under 60000 psi per SAAMI methods.
Now, this is all based on information I have been able to dig up over the last six or eight years, and not just data in the Western Powders reloading guide. I am referring to US Military documents. There MAY be documents I have yet to see, where pressures (SCATP) exceed 58600 psi. When I see them, I'll believe them. Until then...nope.
NATO 5.56 is nominally 62 kpsi, but the standard, which includes pressure measurement methods, is EPVAT. EPVAT pressure measurement is similar to that used in CIP (but not the same).
The US military does not adhere to the EPVAT standard, but rather employs the SCATP standard. SCATP prescribes the very same pressure measurement methods utilized by SAAMI. The highest pressures in any spec (and I mean actual US military documents) I have been able to locate are about 58,600 psi (IIRC).
I am not too concerned about .223 ammo being loaded to about 58000 psi (and I'm talking SAAMI, as we usually speak of pressures) , but I am not so sure I'd want to push any handloaded ammo much beyond 58000 psi.
Can .223 brass handle 62000 (SAAMI) psi repeatedly? Maybe, maybe not. Can it handle 62000 (CIP or EPVAT) psi? Evidently it can. But those pressure levels should translate to well under 60000 psi per SAAMI methods.
Now, this is all based on information I have been able to dig up over the last six or eight years, and not just data in the Western Powders reloading guide. I am referring to US Military documents. There MAY be documents I have yet to see, where pressures (SCATP) exceed 58600 psi. When I see them, I'll believe them. Until then...nope.
Re: 5.56 versus .223 pressures - 12/02/19
The longer throat and longer minimum headspace in the 5.56 are about full auto reliability with a range of specialty ammo. The pressure difference due to the chamber differences are all well under SAAMI lot variation allowances. The cases have identical exterior dimensions.
The test barrels probably reflect the differences, but will be their respective minimums. The military also includes a gas port pressure range that has to be met and they allow less velocity variation for a given bullet weight than SAAMI. As a result, military ammo is usually kept a little more carefully near the rating maximums than commercial ammo is.
The test barrels probably reflect the differences, but will be their respective minimums. The military also includes a gas port pressure range that has to be met and they allow less velocity variation for a given bullet weight than SAAMI. As a result, military ammo is usually kept a little more carefully near the rating maximums than commercial ammo is.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by RiverRider
The real question is, 62 kpsi by whose standard?
NATO 5.56 is nominally 62 kpsi, but the standard, which includes pressure measurement methods, is EPVAT. EPVAT pressure measurement is similar to that used in CIP (but not the same).
The US military does not adhere to the EPVAT standard, but rather employs the SCATP standard. SCATP prescribes the very same pressure measurement methods utilized by SAAMI. The highest pressures in any spec (and I mean actual military documents) I have been able to locate are about 58,600 psi (IIRC).
I am not too concerned about .223 ammo being loaded to about 58000 psi (and I'm talking SAAMI, as we usually speak of pressures) , but I am not so sure I'd want to push any handloaded ammo much beyond 58000 psi.
Can .223 brass handle 62000 (SAAMI) psi repeatedly? Maybe, maybe not. Can it handle 62000 (CIP or EPVAT) psi? Evidently it can. But those pressure levels should translate to well under 60000 psi per SAAMI methods.
Now, this is all based on information I have been able to dig up over the last six or eight years, and not just data in the Western Powders reloading guide. I am referring to US Military documents. There MAY be documents I have yet to see, where pressures (SCATP) exceed 58600 psi. When I see them, I'll believe them. Until then...nope.
NATO 5.56 is nominally 62 kpsi, but the standard, which includes pressure measurement methods, is EPVAT. EPVAT pressure measurement is similar to that used in CIP (but not the same).
The US military does not adhere to the EPVAT standard, but rather employs the SCATP standard. SCATP prescribes the very same pressure measurement methods utilized by SAAMI. The highest pressures in any spec (and I mean actual military documents) I have been able to locate are about 58,600 psi (IIRC).
I am not too concerned about .223 ammo being loaded to about 58000 psi (and I'm talking SAAMI, as we usually speak of pressures) , but I am not so sure I'd want to push any handloaded ammo much beyond 58000 psi.
Can .223 brass handle 62000 (SAAMI) psi repeatedly? Maybe, maybe not. Can it handle 62000 (CIP or EPVAT) psi? Evidently it can. But those pressure levels should translate to well under 60000 psi per SAAMI methods.
Now, this is all based on information I have been able to dig up over the last six or eight years, and not just data in the Western Powders reloading guide. I am referring to US Military documents. There MAY be documents I have yet to see, where pressures (SCATP) exceed 58600 psi. When I see them, I'll believe them. Until then...nope.
Hello River
This is information I have scrounged via the internet. I try to get the best information just like you do. I understood that the 5.56 max pressure to be the 62,300 psi. In the stuff I read I did not see kpsi. I'm not familiar with what the k stands for. I do use a SAAMI published number to translate pressure from CUP to PSI. It's CUP x 1.52 -18000. If you have a link to the "k" portion I'd be interested in seeing it. Since I use Western powder in several of my reloads I do see their pressure numbers. Scroll to page 48 for 5.56 pressure numbers.
http:/
kwg
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by kwg020
Originally Posted by RiverRider
The real question is, 62 kpsi by whose standard?
NATO 5.56 is nominally 62 kpsi, but the standard, which includes pressure measurement methods, is EPVAT. EPVAT pressure measurement is similar to that used in CIP (but not the same).
The US military does not adhere to the EPVAT standard, but rather employs the SCATP standard. SCATP prescribes the very same pressure measurement methods utilized by SAAMI. The highest pressures in any spec (and I mean actual military documents) I have been able to locate are about 58,600 psi (IIRC).
I am not too concerned about .223 ammo being loaded to about 58000 psi (and I'm talking SAAMI, as we usually speak of pressures) , but I am not so sure I'd want to push any handloaded ammo much beyond 58000 psi.
Can .223 brass handle 62000 (SAAMI) psi repeatedly? Maybe, maybe not. Can it handle 62000 (CIP or EPVAT) psi? Evidently it can. But those pressure levels should translate to well under 60000 psi per SAAMI methods.
Now, this is all based on information I have been able to dig up over the last six or eight years, and not just data in the Western Powders reloading guide. I am referring to US Military documents. There MAY be documents I have yet to see, where pressures (SCATP) exceed 58600 psi. When I see them, I'll believe them. Until then...nope.
NATO 5.56 is nominally 62 kpsi, but the standard, which includes pressure measurement methods, is EPVAT. EPVAT pressure measurement is similar to that used in CIP (but not the same).
The US military does not adhere to the EPVAT standard, but rather employs the SCATP standard. SCATP prescribes the very same pressure measurement methods utilized by SAAMI. The highest pressures in any spec (and I mean actual military documents) I have been able to locate are about 58,600 psi (IIRC).
I am not too concerned about .223 ammo being loaded to about 58000 psi (and I'm talking SAAMI, as we usually speak of pressures) , but I am not so sure I'd want to push any handloaded ammo much beyond 58000 psi.
Can .223 brass handle 62000 (SAAMI) psi repeatedly? Maybe, maybe not. Can it handle 62000 (CIP or EPVAT) psi? Evidently it can. But those pressure levels should translate to well under 60000 psi per SAAMI methods.
Now, this is all based on information I have been able to dig up over the last six or eight years, and not just data in the Western Powders reloading guide. I am referring to US Military documents. There MAY be documents I have yet to see, where pressures (SCATP) exceed 58600 psi. When I see them, I'll believe them. Until then...nope.
Hello River
This is information I have scrounged via the internet. I try to get the best information just like you do. I understood that the 5.56 max pressure to be the 62,300 psi. In the stuff I read I did not see kpsi. I'm not familiar with what the k stands for. I do use a SAAMI published number to translate pressure from CUP to PSI. It's CUP x 1.52 -18000. If you have a link to the "k" portion I'd be interested in seeing it. Since I use Western powder in several of my reloads I do see their pressure numbers. Scroll to page 48 for 5.56 pressure numbers.
http:/
kwg
The "k" is a multiplier, as in 1000x. Or, 58 kpsi = 58000 psi.
C.U.P. has nothing to do with any of this. CUP figures were the what the old copper crusher method would yield. The copper crusher method has been obsolete since about the 80s, I think. what I am talking about is a difference between the European methods and American method of pressure measurement.
Re: 5.56 versus .223 pressures - 12/02/19
Having run HOT N540 service rifle loads for years, to the tune of likely over 100K of them... the AR can handle more than most give it credit for by far...
Re: 5.56 versus .223 pressures - 12/02/19
They are basically the same.
https://thefiringline.com/forums/showthread.php?t=576657&highlight=56
The different pressure reading is due to different testing equipment and techniques.
Quote
Original spec M193 is 52,000 psi (by copper crusher; so same as SAAMI CUP unit). Original SAAMI spec for 223 Rem is also 52,000 CUP. And why wouldn't they be the same? Remington was involved in developing the round and simply copied it with a new name for civilian use.
Then the trouble started. The NATO countries got reference loads from the U.S., but they used a different measuring apparatus. Their apparatus was a metric copper crusher with slightly different size pistons and they got a projected peak number of 3,700 Bar, or about 53,200 psi from those same reference loads that the US got 52,000 psi from. The CIP copied NATO's number for European-made 223 Remington as their copper crushers were closer to the NATO type. Then NATO started moving to Kistler piezoelectric transducers which measured shared reference loads to project a peak of 4,300 Bar, or about 62,366 psi. So CIP copied that and loads their 223 Remington to 62,366 psi, but using an apparatus closer to NATO's (also a channel transducer reading through a drilled hole in the case, except the NATO EPVAT protocol measures through a hole into the barrel just in front of the case mouth, while CIP uses one through the case 25 mm forward of the head; but the difference would only be perhaps a couple of thousand psi, absolute, and zero if they calibrate to the same reference loads).
At the same time (80's and 90's) SAAMI had also adopted a piezo transducer apparatus, but not the drilled hole type Kistler channel transducer, but rather the conformal piezo transducers that reads over top of the unbroken brass case with a piston tip machined to match the chamber wall, and positioned just below the shoulder and which has different mass and response than the European type. Using the same reference load that gives the Europeans 62,366 psi, they got a peak of 55,000 psi. Why? Different apparatus with different limitations and error sources.
Then there is the U.S. military. If you look at SCATP specs from the 80's they refer to an "approved" type piezo transducer for the newer M855 and related rounds. M855 was rated at 55,000 psi by copper crusher, and they were getting numbers closer to 60,000 psi from them on the transducer. Later they went to the Kistler transducers to match NATO and issued the higher pressure numbers for them. Then in 2012, I understand ATK revised SCATP 5.56 and switched them to the SAAMI type conformal transducer for compatibility with commercial sources.
All this has caused a lot of confusion, as you might imagine. Also, the conformal pressure transducers seem to have improved and the difference from the readings they get on the European style transducers seems to have shrunk, as one Australian study shows. The difference now is mainly at very low pressures where, as you might imagine, the brass has more effect on the percent of the pressure applied to the transducer. One board member asked Federal what they load 5.56 to and they answered about 58,000 psi, which I suspect is taking the slightly warmer 55,000 CUP M855 load and measuring it on the conformal pressure transducer.
In the meanwhile, if you buy S&B or RWS or Norma or Lapua loaded 223 Remington ammunition, you are buying ammo loaded to the same peak pressure spec as 5.56 NATO is loaded to in Europe. At least, it's the same as for 55 grain ball ammo. If it hasn't blown anything up (and it hasn't) you don't need to worry about the pressure difference other than that the more generous NATO chambers may lower the pressure a couple thousand psi as compared to a tight match 223 chamber. But that's less than normal variation in pressure during testing, and actual ammo is seldom all the way exactly to peak anyway. I wouldn't fret about it.
The only glaring discrepancy I've seen is that Western powders has a separate list of loads for 62,366 psi. But the powder charge is not the same as their 55,000 psi loads. This is because, and I called their tech to verify it, they are using a conformal pressure transducer to measure that higher number, and not the European type transducer they should use for that number (I think; but recall the Australian study and it could be the 55,000 psi numbers are now a false low on current production apparatus). Anyway, the bottom line is, the same instrument used to limit to 55,000 psi should not be used to set a 62,366 psi limit as if it were a completely separate number. Only one of those numbers will match original developed load performance when measured on the same apparatus.
Then the trouble started. The NATO countries got reference loads from the U.S., but they used a different measuring apparatus. Their apparatus was a metric copper crusher with slightly different size pistons and they got a projected peak number of 3,700 Bar, or about 53,200 psi from those same reference loads that the US got 52,000 psi from. The CIP copied NATO's number for European-made 223 Remington as their copper crushers were closer to the NATO type. Then NATO started moving to Kistler piezoelectric transducers which measured shared reference loads to project a peak of 4,300 Bar, or about 62,366 psi. So CIP copied that and loads their 223 Remington to 62,366 psi, but using an apparatus closer to NATO's (also a channel transducer reading through a drilled hole in the case, except the NATO EPVAT protocol measures through a hole into the barrel just in front of the case mouth, while CIP uses one through the case 25 mm forward of the head; but the difference would only be perhaps a couple of thousand psi, absolute, and zero if they calibrate to the same reference loads).
At the same time (80's and 90's) SAAMI had also adopted a piezo transducer apparatus, but not the drilled hole type Kistler channel transducer, but rather the conformal piezo transducers that reads over top of the unbroken brass case with a piston tip machined to match the chamber wall, and positioned just below the shoulder and which has different mass and response than the European type. Using the same reference load that gives the Europeans 62,366 psi, they got a peak of 55,000 psi. Why? Different apparatus with different limitations and error sources.
Then there is the U.S. military. If you look at SCATP specs from the 80's they refer to an "approved" type piezo transducer for the newer M855 and related rounds. M855 was rated at 55,000 psi by copper crusher, and they were getting numbers closer to 60,000 psi from them on the transducer. Later they went to the Kistler transducers to match NATO and issued the higher pressure numbers for them. Then in 2012, I understand ATK revised SCATP 5.56 and switched them to the SAAMI type conformal transducer for compatibility with commercial sources.
All this has caused a lot of confusion, as you might imagine. Also, the conformal pressure transducers seem to have improved and the difference from the readings they get on the European style transducers seems to have shrunk, as one Australian study shows. The difference now is mainly at very low pressures where, as you might imagine, the brass has more effect on the percent of the pressure applied to the transducer. One board member asked Federal what they load 5.56 to and they answered about 58,000 psi, which I suspect is taking the slightly warmer 55,000 CUP M855 load and measuring it on the conformal pressure transducer.
In the meanwhile, if you buy S&B or RWS or Norma or Lapua loaded 223 Remington ammunition, you are buying ammo loaded to the same peak pressure spec as 5.56 NATO is loaded to in Europe. At least, it's the same as for 55 grain ball ammo. If it hasn't blown anything up (and it hasn't) you don't need to worry about the pressure difference other than that the more generous NATO chambers may lower the pressure a couple thousand psi as compared to a tight match 223 chamber. But that's less than normal variation in pressure during testing, and actual ammo is seldom all the way exactly to peak anyway. I wouldn't fret about it.
The only glaring discrepancy I've seen is that Western powders has a separate list of loads for 62,366 psi. But the powder charge is not the same as their 55,000 psi loads. This is because, and I called their tech to verify it, they are using a conformal pressure transducer to measure that higher number, and not the European type transducer they should use for that number (I think; but recall the Australian study and it could be the 55,000 psi numbers are now a false low on current production apparatus). Anyway, the bottom line is, the same instrument used to limit to 55,000 psi should not be used to set a 62,366 psi limit as if it were a completely separate number. Only one of those numbers will match original developed load performance when measured on the same apparatus.
https:/
The different pressure reading is due to different testing equipment and techniques.
Re: 5.56 versus .223 pressures - 12/02/19
Nosler has load data for both the 223 and the 5.56.
Note that the powder charges are identical.
and this from Nosler.
TECHNICAL INFORMATION:
The 5.56x45mm NATO cartridge was developed for military use over 50 years ago, and became known as the 223 Remington only when introduced as a commercial round by Remington. Military use notwithstanding, the “5.56” enjoys widespread civilian use in AR-15 style rifles, and is the mainstay of service rifle match competition. Because of the fast-twist rifling used in the 5.56, it will stabilize bullets of up to 80 grains when fired from a 1-8” or faster barrel. Our 80 grain Custom Competition bullet is an excellent choice for extremely long range shooting, but must be fired as a single shot cartridge (this bullet cannot be loaded to magazine length). For magazine length loading in the 5.56, the 69 grain and 77 grain Custom Competition products are excellent choices. If your brass originally had crimped primers, the crimp MUST be removed prior to re-priming. Also, as it is usually necessary to crimp the bullet in place when loading for a semi-auto use, we recommend using a taper crimp. Crimping with a standard seating die (roll crimping) on bullets without a crimping groove can adversely affect accuracy. The data listed in the load data section is safe for use in both 223 Remington and 5.56x45mm cartridges and chambers.
Note that the powder charges are identical.
and this from Nosler.
TECHNICAL INFORMATION:
The 5.56x45mm NATO cartridge was developed for military use over 50 years ago, and became known as the 223 Remington only when introduced as a commercial round by Remington. Military use notwithstanding, the “5.56” enjoys widespread civilian use in AR-15 style rifles, and is the mainstay of service rifle match competition. Because of the fast-twist rifling used in the 5.56, it will stabilize bullets of up to 80 grains when fired from a 1-8” or faster barrel. Our 80 grain Custom Competition bullet is an excellent choice for extremely long range shooting, but must be fired as a single shot cartridge (this bullet cannot be loaded to magazine length). For magazine length loading in the 5.56, the 69 grain and 77 grain Custom Competition products are excellent choices. If your brass originally had crimped primers, the crimp MUST be removed prior to re-priming. Also, as it is usually necessary to crimp the bullet in place when loading for a semi-auto use, we recommend using a taper crimp. Crimping with a standard seating die (roll crimping) on bullets without a crimping groove can adversely affect accuracy. The data listed in the load data section is safe for use in both 223 Remington and 5.56x45mm cartridges and chambers.
Re: 5.56 versus .223 pressures - 12/02/19
The US military documents I have in hand are from various times. The earliest state the nominal pressure of 5.56 NATO to be 52000 CUP. The next iteration states that the nominal pressure is 55000 psi. As earlier stated, the latest document I have been able to acquire states nominal pressure for the highest pressure round to be 58600 psi.
I do not know whether M855A1 has been adopted, shitcanned, or what...but as far as I know, they really stepped up the pressures and it has been found to be hard on the rifles and pressure figures are still classified. If anyone has uncovered newer info on the M855A1 round I'd sure like to know.
I do not know whether M855A1 has been adopted, shitcanned, or what...but as far as I know, they really stepped up the pressures and it has been found to be hard on the rifles and pressure figures are still classified. If anyone has uncovered newer info on the M855A1 round I'd sure like to know.
Re: 5.56 versus .223 pressures - 12/02/19
Re: 5.56 versus .223 pressures - 12/02/19
.223 OCD
Re: 5.56 versus .223 pressures - 12/02/19
Caution: Do not use the Western Powders load data for 5.56×45 without a lot of careful consideration
I was very surprised to see the separate 5.56 loads in the Western load data. That data constitutes a significant misunderstanding. After seeing it, I called Western Powders yesterday afternoon and explained what I am about to explain here. The response of the technician I spoke with was “Oh”; and then, “I’ll pass that along.”
There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None! The two different Maximum Average Pressure (MAP) standards are artifacts of the different measuring instrumentation used here and in the CIP. The same lot of reference cartridges put in a SAAMI or a Lake City conformal transducer that gives readings averaging 55,000 psi will give readings averaging 62,366 psi in European channel transducers. This why the U.S. military and SAAMI specs have a maximum average pressure (MAP) of 55,000 psi and the Europeans have a MAP of 62,366 psi (actually, 4300 bar in their units). The European EVPAT 7.62 and 5.56 test procedures are based on results of their measurements of reference ammunition made in the U.S. using the U.S. test procedures, SCATP 7.62 and 5.56 for NATO compatible ammunition.
From MIL-C-9963F, for CARTRIDGE, 5.56MM, BALL, M193:
Quote:
3.7 Chamber pressure.
3.7.1 Measurement by copper-crush cylinder. -The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 52,000 pounds per square inch (PSI). The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 58,000 PSI.
3.7.2 Measurement by piezoelectric transducer. -The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 55,000 PSI. The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 61,000 PSI.
3.8 port pressure.
3.8.1 Measurement by copper-crush cylinder. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 15,000 PSI ± 2000 PSI.
3.8.2 Measurement by piezoelectric transducer. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 14,400 PSI ± 2000 PSI.
The piezo transducer in 3.7.2, above is a conformal piezoelectric transducer wherein the head of the piston that presses on the piezoelectric element is machined to match the chamber on the inside. This allows a cartridge to be placed into the chamber whole, and the pressure is measured over top of the brass.
The channel transducers used in Europe have a gas checked piston whose head is exposed directly to the propellant gas with no brass in between. The CIP does this by drilling a hole in the case and lining it up with the piston channel during firing, same as we do for copper crushers. The NATO EVPAT procedure samples the gas just in front of the case mouth to avoid the time consuming drilling and aligning.
The reason for the large size of the difference in readings between the two systems is not entirely clear. The brass interference does not account for it. The conformal transducer, for example, give 62,000 psi for .308 and 7.62 NATO ammunition that was 52,000 CUP in a copper crusher, while the channel transducers gives it only 4150 bar (60,191 psi), actually a lower number. The two systems are complicated by CIP having two different metric piston sizes, by masses not being the same, by electronic filtering being necessary to damp ringing in the EVPAT case mouth readings, which have their pressure applied more suddenly than through a drilled case, and selection of which filtering affects the reading values. It’s a very complex set of interactions and about the only thing you can say for sure is the systems don’t track one another.
The above is why reference ammunition is created. Even just within the SAAMI system, because your pressure tester won’t match mine exactly, even after calibration, one manufacturer is given responsibility for each chambering to load and supply reference ammunition to the industry. The reference cartridges are fired and whatever result you get on your system from them becomes the result you will use for your testing limit. Readings may be scaled to that as a correction factor.
In the case of the Western data for 5.56×45, the error is that they didn’t use channel transducers for the higher pressure limit. They used a conformal transducer. That ammunition would be expected to measure up to 4876 bar (70,719 psi) on the European equipment. Also, like most U.S. handloading data, no port pressure testing is done on the assumption the ammunition will be fired in bolt guns. It is not really NATO compatible ammo without gas port testing.
Will this hurt anything? Well, it’s not reaching proof pressures, which would be a minimum of 134% over MAP or 73,500 psi on a SAAMI conformal transducer. The CIP uses a lower percentage increase for proofing than SAAMI does, 125% over MAP, and that works out to 5375 bar (77,958) on a channel transducer. Brass will be stressed harder at this higher pressure, bolt face erosion and throat erosion will accelerate. Gas gun cycling will be harder.
It is interesting to note that when copper crushers were still in use in the original development and specifications for the cartridge, everything was much closer. This is because the way copper crushers were used by the various organizations was more similar. The copper crusher standards for M193 NATO ball ammunition are:
U.S. military: 52,000 psi (CUP, in SAAMI terminology, as this is by copper crusher)
NATO: 3700 bar (53,366 CUP)
The difference is so small as to be statistically insignificant, given the limited precision of copper crushers. Copper crushers have been phased out of military ammunition making, but the numbers are still valid standards and have not been changed.
The commercial .223 Remington copper crusher standards are:
SAAMI: 52,000 CUP
CIP: 3700 bar (53,366 CUP)
The SAAMI standard carried the U.S. military copper crusher MAP into commercial .223 loads, and the CIP standard carried the NATO copper crusher MAP over to commercial use. The European copper crushers use a slightly different pressure port location and a metric size piston, so the readings would not be expected to be exactly the same, even if copper crushers were perfectly repeatable.
Several years ago I had a phone conversation on the general topic of pressure standards with then SAAMI Technical Director, Ken Green (ret. 2011). The specific subject then was the MAPs for .357 and .44 Magnum cartridges. The original MAPs had been 45,000 CUP and 40,000 CUP for the two cartridges, respectively. But in the conformal Piezo transducer they are rated and 35,000 psi, and 36,000 psi, respectively, a decrease of 10,000 units for the .357 Mag, and if 4,000 units for the .44 Mag. Most every Internet pundit seemed to think this meant the two cartridges had been wimped down from their original pressures over liability concerns. Ken Green told me otherwise. He said the exact same reference loads made up in and used for copper crushers were fired in a Piezo transducer simply produced those different results. The two types of instrumentation just don’t track. Most people would like to believe absolute pressure numbers from these measurements were more exact than they actually are, but SAAMI’s own documentation show the same lots of reference ammunition can give results that vary over 23% in copper crushers and 11% in piezo transducers. This is why the reference ammunition is still necessary to keep people on the same page.
The original development of pressure levels for these rounds was done (see Elmer Keith’s work) until the gun being used said “uncle”, and then were backed off a percentage for a safety margin. They were not developed to an instrumentation standard, but to a gun. The instrumentation was applied subsequently to get a pressure standard that could be duplicated in manufacturing. If the absolute pressure standard had actually been lowered between the copper crusher and Piezo transducer standards, then the CUP’s would have been changed downward, too, and not left where they were. You don’t want a manufacturer still using a copper crusher producing different pressure ammunition than one using Piezo equipment. Again, those same copper crusher numbers are still in force, today. You can read the standards on SAAMI’s web site and see for yourself.
The same applies for the rifle rounds. The original pressures and reference loads remain the same. The Piezo numbers are just what SAAMI Piezo equipment reads them to be. It is the same with the CIP. Their copper crusher numbers remain valid, even though they are considered obsolete, because they represent results from the same reference ammunition. So, an unfortunate result is we have close to matching .223 and 5.56 pressures on everybody’s copper crushers, but not on the different piezo transducers.
https://thefiringline.com/forums/showthread.php?t=553455&highlight=piezo
I was very surprised to see the separate 5.56 loads in the Western load data. That data constitutes a significant misunderstanding. After seeing it, I called Western Powders yesterday afternoon and explained what I am about to explain here. The response of the technician I spoke with was “Oh”; and then, “I’ll pass that along.”
There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None! The two different Maximum Average Pressure (MAP) standards are artifacts of the different measuring instrumentation used here and in the CIP. The same lot of reference cartridges put in a SAAMI or a Lake City conformal transducer that gives readings averaging 55,000 psi will give readings averaging 62,366 psi in European channel transducers. This why the U.S. military and SAAMI specs have a maximum average pressure (MAP) of 55,000 psi and the Europeans have a MAP of 62,366 psi (actually, 4300 bar in their units). The European EVPAT 7.62 and 5.56 test procedures are based on results of their measurements of reference ammunition made in the U.S. using the U.S. test procedures, SCATP 7.62 and 5.56 for NATO compatible ammunition.
From MIL-C-9963F, for CARTRIDGE, 5.56MM, BALL, M193:
Quote:
3.7 Chamber pressure.
3.7.1 Measurement by copper-crush cylinder. -The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 52,000 pounds per square inch (PSI). The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 58,000 PSI.
3.7.2 Measurement by piezoelectric transducer. -The average chamber pressure of the sample cartridges, conditioned at 70° ± 2°F, shall not exceed 55,000 PSI. The average chamber pressure plus three standard deviations of chamber pressure shall not exceed 61,000 PSI.
3.8 port pressure.
3.8.1 Measurement by copper-crush cylinder. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 15,000 PSI ± 2000 PSI.
3.8.2 Measurement by piezoelectric transducer. -The average port pressure of the sample cartridges, conditioned at 70° ± 2°F, shall be 14,400 PSI ± 2000 PSI.
The piezo transducer in 3.7.2, above is a conformal piezoelectric transducer wherein the head of the piston that presses on the piezoelectric element is machined to match the chamber on the inside. This allows a cartridge to be placed into the chamber whole, and the pressure is measured over top of the brass.
The channel transducers used in Europe have a gas checked piston whose head is exposed directly to the propellant gas with no brass in between. The CIP does this by drilling a hole in the case and lining it up with the piston channel during firing, same as we do for copper crushers. The NATO EVPAT procedure samples the gas just in front of the case mouth to avoid the time consuming drilling and aligning.
The reason for the large size of the difference in readings between the two systems is not entirely clear. The brass interference does not account for it. The conformal transducer, for example, give 62,000 psi for .308 and 7.62 NATO ammunition that was 52,000 CUP in a copper crusher, while the channel transducers gives it only 4150 bar (60,191 psi), actually a lower number. The two systems are complicated by CIP having two different metric piston sizes, by masses not being the same, by electronic filtering being necessary to damp ringing in the EVPAT case mouth readings, which have their pressure applied more suddenly than through a drilled case, and selection of which filtering affects the reading values. It’s a very complex set of interactions and about the only thing you can say for sure is the systems don’t track one another.
The above is why reference ammunition is created. Even just within the SAAMI system, because your pressure tester won’t match mine exactly, even after calibration, one manufacturer is given responsibility for each chambering to load and supply reference ammunition to the industry. The reference cartridges are fired and whatever result you get on your system from them becomes the result you will use for your testing limit. Readings may be scaled to that as a correction factor.
In the case of the Western data for 5.56×45, the error is that they didn’t use channel transducers for the higher pressure limit. They used a conformal transducer. That ammunition would be expected to measure up to 4876 bar (70,719 psi) on the European equipment. Also, like most U.S. handloading data, no port pressure testing is done on the assumption the ammunition will be fired in bolt guns. It is not really NATO compatible ammo without gas port testing.
Will this hurt anything? Well, it’s not reaching proof pressures, which would be a minimum of 134% over MAP or 73,500 psi on a SAAMI conformal transducer. The CIP uses a lower percentage increase for proofing than SAAMI does, 125% over MAP, and that works out to 5375 bar (77,958) on a channel transducer. Brass will be stressed harder at this higher pressure, bolt face erosion and throat erosion will accelerate. Gas gun cycling will be harder.
It is interesting to note that when copper crushers were still in use in the original development and specifications for the cartridge, everything was much closer. This is because the way copper crushers were used by the various organizations was more similar. The copper crusher standards for M193 NATO ball ammunition are:
U.S. military: 52,000 psi (CUP, in SAAMI terminology, as this is by copper crusher)
NATO: 3700 bar (53,366 CUP)
The difference is so small as to be statistically insignificant, given the limited precision of copper crushers. Copper crushers have been phased out of military ammunition making, but the numbers are still valid standards and have not been changed.
The commercial .223 Remington copper crusher standards are:
SAAMI: 52,000 CUP
CIP: 3700 bar (53,366 CUP)
The SAAMI standard carried the U.S. military copper crusher MAP into commercial .223 loads, and the CIP standard carried the NATO copper crusher MAP over to commercial use. The European copper crushers use a slightly different pressure port location and a metric size piston, so the readings would not be expected to be exactly the same, even if copper crushers were perfectly repeatable.
Several years ago I had a phone conversation on the general topic of pressure standards with then SAAMI Technical Director, Ken Green (ret. 2011). The specific subject then was the MAPs for .357 and .44 Magnum cartridges. The original MAPs had been 45,000 CUP and 40,000 CUP for the two cartridges, respectively. But in the conformal Piezo transducer they are rated and 35,000 psi, and 36,000 psi, respectively, a decrease of 10,000 units for the .357 Mag, and if 4,000 units for the .44 Mag. Most every Internet pundit seemed to think this meant the two cartridges had been wimped down from their original pressures over liability concerns. Ken Green told me otherwise. He said the exact same reference loads made up in and used for copper crushers were fired in a Piezo transducer simply produced those different results. The two types of instrumentation just don’t track. Most people would like to believe absolute pressure numbers from these measurements were more exact than they actually are, but SAAMI’s own documentation show the same lots of reference ammunition can give results that vary over 23% in copper crushers and 11% in piezo transducers. This is why the reference ammunition is still necessary to keep people on the same page.
The original development of pressure levels for these rounds was done (see Elmer Keith’s work) until the gun being used said “uncle”, and then were backed off a percentage for a safety margin. They were not developed to an instrumentation standard, but to a gun. The instrumentation was applied subsequently to get a pressure standard that could be duplicated in manufacturing. If the absolute pressure standard had actually been lowered between the copper crusher and Piezo transducer standards, then the CUP’s would have been changed downward, too, and not left where they were. You don’t want a manufacturer still using a copper crusher producing different pressure ammunition than one using Piezo equipment. Again, those same copper crusher numbers are still in force, today. You can read the standards on SAAMI’s web site and see for yourself.
The same applies for the rifle rounds. The original pressures and reference loads remain the same. The Piezo numbers are just what SAAMI Piezo equipment reads them to be. It is the same with the CIP. Their copper crusher numbers remain valid, even though they are considered obsolete, because they represent results from the same reference ammunition. So, an unfortunate result is we have close to matching .223 and 5.56 pressures on everybody’s copper crushers, but not on the different piezo transducers.
https:/
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by RiverRider
The US military documents I have in hand are from various times. The earliest state the nominal pressure of 5.56 NATO to be 52000 CUP. The next iteration states that the nominal pressure is 55000 psi. As earlier stated, the latest document I have been able to acquire states nominal pressure for the highest pressure round to be 58600 psi.
I do not know whether M855A1 has been adopted, shitcanned, or what...but as far as I know, they really stepped up the pressures and it has been found to be hard on the rifles and pressure figures are still classified. If anyone has uncovered newer info on the M855A1 round I'd sure like to know.
I do not know whether M855A1 has been adopted, shitcanned, or what...but as far as I know, they really stepped up the pressures and it has been found to be hard on the rifles and pressure figures are still classified. If anyone has uncovered newer info on the M855A1 round I'd sure like to know.
Hello River
It seems we have information over load in the last 20 minutes. Several other members have entered some good information. Steve4102 had some really logical information that I had never seen before as well. His post is just 1 or 2 ahead of yours.
Another powder I like is Hodgdons Benchmark. The powder load for a 55 grain (M193) soft point is 25.6 grains of powder to make 50,000 CUP. When I use the SAAMI CUP to PSI formula I get 58,000 PSI. I'm going to assume (yes, I know what it means) since the powder is called Benchmark that means it is a 5.56 NATO pressure load as reached by the new measuring standards (?).
Which is really confusing since Western apparently uses a different process for measuring pressure and uses the 62,350 number as max NATO pressure. I got it. Clear as mud.
kwg
Re: 5.56 versus .223 pressures - 12/02/19
Everybody who has blowed up a .223 by shooting 5.56 in it,....raise your hand.
Re: 5.56 versus .223 pressures - 12/02/19
From MIL-PRF-71208-AR, regarding M995 armor piercing 5.56 ammo. Evidently I misremembered the highest pressure figure I had ever found, but it's right here. The concern with temperature factors is interesting. These figures are all per SCATP methods:
3.5.2 Chamber pressure.
3.5.2.1 Chamber pressure at 70ºF. The average chamber pressure of cartridges,
conditioned at 70 F ± 2ºF (21 C ± 1.1 C), shall be not greater than 59,700 psi (411.6 MPa).
Neither the chamber pressure of an individual cartridge nor the average chamber pressure plus
three standard deviations of chamber pressure shall be greater than 64,700 psi (446.1 MPa).
3.5.2.2 Chamber pressure at extreme temperatures. The average chamber pressure of
cartridges conditioned at -65 F ± 2ºF (-54 C ± 1.1 C) and at 125 F ± 2ºF (52 C ± 1.1 C) shall
not vary from the average chamber pressure of cartridges conditioned at 70 F ± 2ºF
(21 C ± 1.1 C) by more than 7,000 psi (48.3 MPa), and shall be not greater than 64,700 psi
(446.1 MPa).
3.5.2 Chamber pressure.
3.5.2.1 Chamber pressure at 70ºF. The average chamber pressure of cartridges,
conditioned at 70 F ± 2ºF (21 C ± 1.1 C), shall be not greater than 59,700 psi (411.6 MPa).
Neither the chamber pressure of an individual cartridge nor the average chamber pressure plus
three standard deviations of chamber pressure shall be greater than 64,700 psi (446.1 MPa).
3.5.2.2 Chamber pressure at extreme temperatures. The average chamber pressure of
cartridges conditioned at -65 F ± 2ºF (-54 C ± 1.1 C) and at 125 F ± 2ºF (52 C ± 1.1 C) shall
not vary from the average chamber pressure of cartridges conditioned at 70 F ± 2ºF
(21 C ± 1.1 C) by more than 7,000 psi (48.3 MPa), and shall be not greater than 64,700 psi
(446.1 MPa).
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by kwg020
When I use the SAAMI CUP to PSI formula I get 58,000 PSI. I'm going to assume (yes, I know what it means) since the powder is called Benchmark that means it is a 5.56 NATO pressure load as reached by the new measuring standards (?).
Which is really confusing since Western apparently uses a different process for measuring pressure and uses the 62,350 number as max NATO pressure. I got it. Clear as mud.
kwg
Which is really confusing since Western apparently uses a different process for measuring pressure and uses the 62,350 number as max NATO pressure. I got it. Clear as mud.
kwg
KWG: The CUP to PSI conversion (and where did you find that formula anyway??) has nothing at all to do with the differences between American and European pressure measurement methods, whether they be military or civilian.
Copper crusher is no longer used. CUP figures are obsolete (even though some loading data with CUP pressure figures still persists).
Re: 5.56 versus .223 pressures - 12/02/19
I don't know how some people posting in this thread can touch off a handload without suffering a nervous breakdown.
The first propellant I ever used was powdered match heads.
The first propellant I ever used was powdered match heads.
Re: 5.56 versus .223 pressures - 12/02/19
Hello Steve 4102
"There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None!"
If what I'm reading is good information, then why do we need a NATO chamber ? RiverRunner brought up the M855 ammo as well. It does seem to be significantly "hotter" than standard NATO loads.
So, why do we need a NATO chamber ?
kwg
"There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None!"
If what I'm reading is good information, then why do we need a NATO chamber ? RiverRunner brought up the M855 ammo as well. It does seem to be significantly "hotter" than standard NATO loads.
So, why do we need a NATO chamber ?
kwg
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by Bristoe
I don't know how some people posting in this thread can touch off a handload without suffering a nervous breakdown.
The first propellant I ever used was powdered match heads.
The first propellant I ever used was powdered match heads.
If it's all too far over your pointy little head, then why don't you sit down and shut the f### up?
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by kwg020
Hello Steve 4102
"There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None!"
If what I'm reading is good information, then why do we need a NATO chamber ? RiverRunner brought up the M855 ammo as well. It does seem to be significantly "hotter" than standard NATO loads.
So, why do we need a NATO chamber ?
kwg
"There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None!"
If what I'm reading is good information, then why do we need a NATO chamber ? RiverRunner brought up the M855 ammo as well. It does seem to be significantly "hotter" than standard NATO loads.
So, why do we need a NATO chamber ?
kwg
Longer throat for heavier bullets, different twist for heavier bullets. Battle field conditions. Some say that a tighter chamber (223) is more accurate.
Here is what Nosler says about their difference in 5.56 and 223 data.
TECHNICAL INFORMATION:
The 5.56x45mm NATO cartridge was developed for military use over 50 years ago, and became known as the 223 Remington only when introduced as a commercial round by Remington. Military use notwithstanding, the “5.56” enjoys widespread civilian use in AR-15 style rifles, and is the mainstay of service rifle match competition. Because of the fast-twist rifling used in the 5.56, it will stabilize bullets of up to 80 grains when fired from a 1-8” or faster barrel. Our 80 grain Custom Competition bullet is an excellent choice for extremely long range shooting, but must be fired as a single shot cartridge (this bullet cannot be loaded to magazine length). For magazine length loading in the 5.56, the 69 grain and 77 grain Custom Competition products are excellent choices. If your brass originally had crimped primers, the crimp MUST be removed prior to re-priming. Also, as it is usually necessary to crimp the bullet in place when loading for a semi-auto use, we recommend using a taper crimp. Crimping with a standard seating die (roll crimping) on bullets without a crimping groove can adversely affect accuracy. The data listed in the load data section is safe for use in both 223 Remington and 5.56x45mm cartridges and chambers.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by RiverRider
Originally Posted by Bristoe
I don't know how some people posting in this thread can touch off a handload without suffering a nervous breakdown.
The first propellant I ever used was powdered match heads.
The first propellant I ever used was powdered match heads.
If it's all too far over your pointy little head, then why don't you sit down and shut the f### up?
My goodness!
Re: 5.56 versus .223 pressures - 12/02/19
,...another one of those excitable people.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by Bristoe
Originally Posted by RiverRider
Originally Posted by Bristoe
I don't know how some people posting in this thread can touch off a handload without suffering a nervous breakdown.
The first propellant I ever used was powdered match heads.
The first propellant I ever used was powdered match heads.
If it's all too far over your pointy little head, then why don't you sit down and shut the f### up?
My goodness!
What goodness? You've destroyed that illusion. Pretend to not know what I'm talking about.
Originally Posted by Bristoe
,...another one of those excitable people.
Nope...just giving you deserved recognition for your trolling.
Re: 5.56 versus .223 pressures - 12/02/19
So why don't you f*** off so we can have an intelligent discussion.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by RiverRider
What goodness? You've destroyed that illusion. Pretend to not know what I'm talking about.
I don't have to pretend.
What are you talking about?
Spell it out.
Re: 5.56 versus .223 pressures - 12/02/19
I won't play games with you. GFY.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by Bristoe
Everybody who has blowed up a .223 by shooting 5.56 in it,....raise your hand.
He didn't have a blow up, but a buddy shooting M855 in a Rock River had definite issues with pressure signs.
Extremely flat primers and and a couple leaked a little.
I shot a ton of that ammo in my AR the same day and never had a problem.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by steve4102
Originally Posted by kwg020
Hello Steve 4102
"There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None!"
If what I'm reading is good information, then why do we need a NATO chamber ? RiverRunner brought up the M855 ammo as well. It does seem to be significantly "hotter" than standard NATO loads.
So, why do we need a NATO chamber ?
kwg
"There is no difference in absolute pressure between .223 Remington and 5.56 NATO. None!"
If what I'm reading is good information, then why do we need a NATO chamber ? RiverRunner brought up the M855 ammo as well. It does seem to be significantly "hotter" than standard NATO loads.
So, why do we need a NATO chamber ?
kwg
Longer throat for heavier bullets, different twist for heavier bullets. Battle field conditions. Some say that a tighter chamber (223) is more accurate.
Here is what Nosler says about their difference in 5.56 and 223 data.
TECHNICAL INFORMATION:
The 5.56x45mm NATO cartridge was developed for military use over 50 years ago, and became known as the 223 Remington only when introduced as a commercial round by Remington. Military use notwithstanding, the “5.56” enjoys widespread civilian use in AR-15 style rifles, and is the mainstay of service rifle match competition. Because of the fast-twist rifling used in the 5.56, it will stabilize bullets of up to 80 grains when fired from a 1-8” or faster barrel. Our 80 grain Custom Competition bullet is an excellent choice for extremely long range shooting, but must be fired as a single shot cartridge (this bullet cannot be loaded to magazine length). For magazine length loading in the 5.56, the 69 grain and 77 grain Custom Competition products are excellent choices. If your brass originally had crimped primers, the crimp MUST be removed prior to re-priming. Also, as it is usually necessary to crimp the bullet in place when loading for a semi-auto use, we recommend using a taper crimp. Crimping with a standard seating die (roll crimping) on bullets without a crimping groove can adversely affect accuracy. The data listed in the load data section is safe for use in both 223 Remington and 5.56x45mm cartridges and chambers.
That's good information but I'm not ready to give up my .223 vs NATO mindset yet. I know that NATO ammo is typically loaded with slower burning powders and that tends to reduce chamber pressure and allows for heavier bullets and higher velocities. I'm just not convinced yet that the longer NATO chambers are just for heavier and longer bullets or ease of extraction. Especially with NATO loads chewing up bolts and bolt carriers under heavy use. I do think it's time for the folks who make gun powder and ammunition come up with a single way of determining pressure and if chambers really makes a difference. Great discussion.
kwg
Re: 5.56 versus .223 pressures - 12/02/19
Lets look at some examples of Factory ammo in both the 223 and the 5.56.
I'm going to post Velocities as pressure data is not listed.
Frontier Cartridge Military Grade Ammunition 223 Remington 55 Grain Hornady Hollow Point Match
Velocity=3240 fps
https://www.midwayusa.com/product/1019565932
Frontier Cartridge Military Grade Ammunition 5.56x45mm NATO 55 Grain Hornady Hollow Point Match
Velocity 3240 fps
https://www.midwayusa.com/product/1019566463
______________________________
Winchester USA Ammunition 223 Remington 55 Grain Full Metal Jacket
Velocity 3240 fps
https://www.midwayusa.com/product/2900275599
Winchester USA Ammunition 5.56x45mm NATO 55 Grain Full Metal Jacket Ammo Can of 300
Velocity 3240 fps
https://www.midwayusa.com/product/1021730794?pid=951734
__________________________________
Hornady BLACK Ammunition 223 Remington 75 Grain Hollow Point Boat Tail Match Box of 20
Velocity 2790 fps
https://www.midwayusa.com/product/101822625?pid=882342
Hornady BLACK Ammunition 5.56x45mm NATO 75 Grain Interlock HD SBR Box of 20
Velocity 2321 fps
https://www.midwayusa.com/product/1018227091?pid=966793
_______________
I could do this all day long, but you get the picture. Velocities are either identical or the 5.56 is slower.
Different chambers etc. can all play a factor in pressure and velocity, but logical thinking says that if these Ammunition manufacturers are producing identical velocities with both types of ammo, the pressures are also identical. If not, they are to close to give a shcit about.
I'm going to post Velocities as pressure data is not listed.
Frontier Cartridge Military Grade Ammunition 223 Remington 55 Grain Hornady Hollow Point Match
Velocity=3240 fps
https:/
Frontier Cartridge Military Grade Ammunition 5.56x45mm NATO 55 Grain Hornady Hollow Point Match
Velocity 3240 fps
https:/
______________________________
Winchester USA Ammunition 223 Remington 55 Grain Full Metal Jacket
Velocity 3240 fps
https:/
Winchester USA Ammunition 5.56x45mm NATO 55 Grain Full Metal Jacket Ammo Can of 300
Velocity 3240 fps
https:/
__________________________________
Hornady BLACK Ammunition 223 Remington 75 Grain Hollow Point Boat Tail Match Box of 20
Velocity 2790 fps
https:/
Hornady BLACK Ammunition 5.56x45mm NATO 75 Grain Interlock HD SBR Box of 20
Velocity 2321 fps
https:/
_______________
I could do this all day long, but you get the picture. Velocities are either identical or the 5.56 is slower.
Different chambers etc. can all play a factor in pressure and velocity, but logical thinking says that if these Ammunition manufacturers are producing identical velocities with both types of ammo, the pressures are also identical. If not, they are to close to give a shcit about.
Re: 5.56 versus .223 pressures - 12/02/19
I think we're in complete agreement. Do you not see it that way?
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by Sasha_and_Abby
I have three rifles chambered in 5.56 NATO. Why can’t I reload .223 casings to the same pressures and velocity.? I would like to be getting around 3000 ft./s with 62 grain cup And core soft points.
22 inch barrel I assume?
You should be able to achieve 3000fps with a 62gr bullet.
Hodgdon list 3110 fps with a 24 inch barrel
Lyman list 3244 with a 24 inch barrel.
Quickload calculates velocity loss from 24 inch down to 22 inch about 60 fps.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by RiverRider
I think we're in complete agreement. Do you not see it that way?
Are you referring to me?
Then yes.
Re: 5.56 versus .223 pressures - 12/02/19
Originally Posted by steve4102
Longer throat for heavier bullets, different twist for heavier bullets. Battle field conditions. Some say that a tighter chamber (223) is more accurate.
[/b]
Actually, it's longer bullets.[i][/i].
M856 tracer ammo is even longer than some 80 gr. bullets. Also, M855 has steel in them, making them longer than a given 62 gr all lead bullet.
Faster twist in MIL A2's came about due to the new bullets' length, not weight. FWIW, length determines required twist, not weight. With all lead jacketed bullets, more weight and longer bullet are generally hand in hand, with composite and non-lead bullets, that is no longer the case.
Re: 5.56 versus .223 pressures - 12/02/19
This ...
I was going to post the chamber dimensions, but this is it...
NOW... the problem is after you load a 223 to 5.56 Pressures and they get mixed up in a bag, how to you make sure they don’t get put into the 223 by mistake... Big Trouble in little Chamber..
I was going to post the chamber dimensions, but this is it...
NOW... the problem is after you load a 223 to 5.56 Pressures and they get mixed up in a bag, how to you make sure they don’t get put into the 223 by mistake... Big Trouble in little Chamber..
Originally Posted by NVhntr
The difference is in the chamber dimensions, not the brass. The primary difference is the 5.56 NATO chamber has a slightly longer throat to lower chamber pressure compared to the .223 chamber.
There should be no problem loading .223 stamped brass to 5.56 NATO pressure as long as you fire it in a 5.56 NATO chamber.
There should be no problem loading .223 stamped brass to 5.56 NATO pressure as long as you fire it in a 5.56 NATO chamber.
Re: 5.56 versus .223 pressures - 12/06/19
This has been beat to death for years. The neck on almost all 223 is too long and will not close on 5.56 ammo, almost all!
5.56 brass cut to length is just fine if you load lite and work up.
Don’t believe me? Go buy some HSM 223 reman ammo, they sell it commercially as 223. every. single. head-stamp. 5.56.
And HSM ammo lived happily ever after. (Stevensville Montana, Right by Cooper Firearms, Just south of Los Angeles de Montana)
THE END.
5.56 brass cut to length is just fine if you load lite and work up.
Don’t believe me? Go buy some HSM 223 reman ammo, they sell it commercially as 223. every. single. head-stamp. 5.56.
And HSM ammo lived happily ever after. (Stevensville Montana, Right by Cooper Firearms, Just south of Los Angeles de Montana)
THE END.
Re: 5.56 versus .223 pressures - 12/06/19
I've seen 5.56 pressures quoted as being 20% higher than commercial 223 pressures. But I'd bet that any repeaters are cut to 5.56 chamber dimensions, unless it's a specific match gun. They'd be crazy, liability wise, to not do so.
Re: 5.56 versus .223 pressures - 12/06/19
my eyes rolled back in my head 25 years ago due to this argument. shoot em if you got them.
mostly it is a moot argument for me as i load for accuracy and invariably the best load is less then max.
mostly it is a moot argument for me as i load for accuracy and invariably the best load is less then max.
Re: 5.56 versus .223 pressures - 12/06/19
without a bipod in prone, nobody can reliably group better than 1 moa anyway and that's without target movement, wind, mirage, etc. You can have a nice 1" group that's 2" off of center. :-) Reliably hitting 1" disks at 100 yds, under field conditions, sitting with a long bipod, is very tough, Prone usually means that rolling hills, bad upward angles, or vegetaton block your view. 1" at 100 yds does NOT equal 2" at 200 yds, either, normally due to slight variations in the holding the rifle, relative to a straight up and and down angle to gravity, but also to wind drift and mirage. So all this sub 1 moa talk is bs in the first place.