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Joined: Dec 2002
Posts: 25,933 Likes: 6
Campfire Ranger
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Campfire Ranger
Joined: Dec 2002
Posts: 25,933 Likes: 6 |
Bullet type has to be accounted for when loading for rifles. One example I ran into was with the 6mm 100 grain Hornady round nose. The 100 grain 6mm round nose was almost like a wadcutter with a round nose. That's to say, almost the entire length of the bullet was bearing surface.
I loaded up a batch with 40 grains of H4350 in the .243. 40 grains of H4350 with a 100 grain bullet isn't a maximum load in the .243. But using those long bearing surface 100 grain RN bullets with 40 grains of H4350 would hammer the primers flat and expand the primer pockets so much that the cases couldn't be used again.
Hornady stopped producing those bullets shortly after I tried them. I suspect that others found out what I did,...that so much of the bullet was in contact with the rifling that 100 grain .243 load data was too hot for them. The same phemenon can be observed when swithing from cup and core spitzer boat tails to the Nosler Partition if using the same powder charge The partition yields higher pressures coupled with higher velocities.
People who choose to brew up their own storms bitch loudest about the rain.
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Joined: Aug 2005
Posts: 28,259 Likes: 6
Campfire Ranger
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Campfire Ranger
Joined: Aug 2005
Posts: 28,259 Likes: 6 |
Bullet type has to be accounted for when loading for rifles. One example I ran into was with the 6mm 100 grain Hornady round nose. The 100 grain 6mm round nose was almost like a wadcutter with a round nose. That's to say, almost the entire length of the bullet was bearing surface.
I loaded up a batch with 40 grains of H4350 in the .243. 40 grains of H4350 with a 100 grain bullet isn't a maximum load in the .243. But using those long bearing surface 100 grain RN bullets with 40 grains of H4350 would hammer the primers flat and expand the primer pockets so much that the cases couldn't be used again.
Hornady stopped producing those bullets shortly after I tried them. I suspect that others found out what I did,...that so much of the bullet was in contact with the rifling that 100 grain .243 load data was too hot for them. The same phemenon can be observed when swithing from cup and core spitzer boat tails to the Nosler Partition if using the same powder charge The partition yields higher pressures coupled with higher velocities. Increased bearing surface of a bullet will tend to do that.
It is irrelevant what you think. What matters is the TRUTH.
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Joined: Oct 2005
Posts: 79,321 Likes: 2
Campfire Oracle
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Campfire Oracle
Joined: Oct 2005
Posts: 79,321 Likes: 2 |
If published load data says that a particular charge will generate 2700 fps and you get 3000 fps, is that an indicator of excess pressure? Sometimes,...sometimes not. How would "you" know this? Can't have excessive velocity without excessive pressure. Just the way it is. That's not an absolute. Generally speaking, load manuals list loads at a given, industry standard pressure. Power Pistol is only two positions below Unique on the powder burn rate chart. Yet Power Pistol gives quite a bit more velocity that can be achieved with Unique in many handgun chamberings despite the fact that they're very close in burn rate.
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Joined: May 2018
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Campfire Regular
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Campfire Regular
Joined: May 2018
Posts: 1,509 |
When the seems upset and says "everything's fine" when asked.
Old guy, old guns.
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Joined: Dec 2002
Posts: 25,933 Likes: 6
Campfire Ranger
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Campfire Ranger
Joined: Dec 2002
Posts: 25,933 Likes: 6 |
Ever seen any data giving the 308 and a 150 grain bullet 2650 fps and Bullseye being the shown powder? No. But the principal remains. All else being equal, faster powders will generate more pressure at a given velocity. Velocity can't be used to gauge pressure. Correct it’s not a gauge, just as your Hornady Round Nose bullets expanding primer pockets is not “a Gauge”. If you're using a load that's stretching the primers pockets first time out, you're over pressure. Believe it. Absolutely correct. But according to your criteria. It is still not a guage, as you have no idea what pressure was required to expand the primer pockets of this particular piece of brass. Proper use of a Chrony could have warned of excessive pressure/velocity, before you ruined your brass. And yes, I have ruined my share of brass. I have managed, while experimenting, to expand brass enough that it would not fit into the shell holder on my press.
People who choose to brew up their own storms bitch loudest about the rain.
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Joined: May 2018
Posts: 1,509
Campfire Regular
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Campfire Regular
Joined: May 2018
Posts: 1,509 |
Old guy, old guns.
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Joined: Dec 2002
Posts: 25,933 Likes: 6
Campfire Ranger
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Campfire Ranger
Joined: Dec 2002
Posts: 25,933 Likes: 6 |
If published load data says that a particular charge will generate 2700 fps and you get 3000 fps, is that an indicator of excess pressure? Sometimes,...sometimes not. How would "you" know this? Can't have excessive velocity without excessive pressure. Just the way it is. That's not an absolute. Generally speaking, load manuals list loads at a given, industry standard pressure. Power Pistol is only two positions below Unique on the powder burn rate chart. Yet Power Pistol gives quite a bit more velocity that can be achieved with Unique in many handgun chamberings despite the fact that they're very close in burn rate. Burn rates change, and even trade places depending on chamber pressure. While a powder A might be 1% slower than powder B at 18,000 PSI. The difference might be much more significant at 25,000 PSI.
People who choose to brew up their own storms bitch loudest about the rain.
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Joined: Feb 2020
Posts: 7,243 Likes: 3
Campfire Tracker
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Campfire Tracker
Joined: Feb 2020
Posts: 7,243 Likes: 3 |
I'd keep adding more powder until the correct brass headstamp showed-up on the bolt face.
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Joined: Jun 2004
Posts: 44,863 Likes: 4
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jun 2004
Posts: 44,863 Likes: 4 |
Ever seen any data giving the 308 and a 150 grain bullet 2650 fps and Bullseye being the shown powder? No. But the principal remains. All else being equal, faster powders will generate more pressure at a given velocity. Velocity can't be used to gauge pressure.In and of itself, then no. But the implicit assumption is an appropriate powder is being used. If I'm using 4064 in that example and I'm getting higher velocities than other sources show for similar charge weights and barrel lengths, then it's a good bet I have higher pressures and not one of those magical "fast barrels" we sometimes hear about.
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Joined: Jun 2004
Posts: 11,116 Likes: 1
Campfire Outfitter
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Campfire Outfitter
Joined: Jun 2004
Posts: 11,116 Likes: 1 |
Burn rate, powder charge, case capacity, chamber geometry, bullet geometry, bullet mass, etc drive pressure. Propellant gas force, friction, and barrel length drive muzzle velocity.
Muzzle velocity is very highly correlated with peak pressure for any given powder, and so can be an excellent indicator.
Be not weary in well doing.
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Joined: Oct 2005
Posts: 79,321 Likes: 2
Campfire Oracle
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Campfire Oracle
Joined: Oct 2005
Posts: 79,321 Likes: 2 |
Ever seen any data giving the 308 and a 150 grain bullet 2650 fps and Bullseye being the shown powder? No. But the principal remains. All else being equal, faster powders will generate more pressure at a given velocity. Velocity can't be used to gauge pressure. Correct it’s not a gauge, just as your Hornady Round Nose bullets expanding primer pockets is not “a Gauge”. If you're using a load that's stretching the primers pockets first time out, you're over pressure. Believe it. Absolutely correct. But according to your criteria. It is still not a guage, as you have no idea what pressure was required to expand the primer pockets of this particular piece of brass. Proper use of a Chrony could have warned of excessive pressure/velocity, before you ruined your brass. And yes, I have ruined my share of brass. I have managed, while experimenting, to expand brass enough that it would not fit into the shell holder on my press. As mentioned, I swelled the primer pockets out of some .243 brass using a load that was listed as below maximum. I didn't check velocity. But I doubt if the velocity was excessive. The pressure in the cartridge was high because the long bearing surface of that particular bullet was creating much higher than typical drag as it passed down the barrel. That excessive drag could very well have caused velocities to be lower even though it pushed pressures higher. Chronographs don't measure pressure. That's it. That's all.
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Joined: Feb 2013
Posts: 21,807 Likes: 8
Campfire Ranger
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OP
Campfire Ranger
Joined: Feb 2013
Posts: 21,807 Likes: 8 |
I'd keep adding more powder until the correct brass headstamp showed-up on the bolt face. LOL... ya got me.
If you are not actively engaging EVERY enemy you encounter... you are allowing another to fight for you... and that is cowardice... plain and simple.
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Joined: Nov 2021
Posts: 538
Campfire Regular
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Campfire Regular
Joined: Nov 2021
Posts: 538 |
Worked with a guy in the mid 80's who took a 25-06 Ruger 77V tanger & a 308 77R tanger to the shooting bench for a sight in session. Him & the son were arguing....as usual, not paying attention, he fired a 308 round out of the 25-06. I saw it happen. The flame came out of the receiver vent hole like he was shooting a flintlock. Cracked the stock behind the tang & behind the trigger guard. Took a wooden 2x4 block & hammer to get the bolt to lift. He used the same block to pound the bolt rearward but sheared the rim off of the case. Used a hydraulic press & steel rod to push the empty casing from the chamber. Looked like a straight walled case. He sent it back to Ruger, they replaced the barrel, bolt, & stock (free of charge) but reused the receiver as the serial number was the same, which I thought was odd that they would trust it to be reusable. He also got a long written letter on what a bone headed mistake he made and how lucky he was.
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Joined: Jan 2005
Posts: 38,901 Likes: 6
Campfire 'Bwana
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Campfire 'Bwana
Joined: Jan 2005
Posts: 38,901 Likes: 6 |
Wouldn't be surprised if the bullet from that .308 round didn't hit dead center - inherent accuracy, you know.
Not a real member - just an ordinary guy who appreciates being able to hang around and say something once in awhile.
Happily Trapped In the Past (Thanks, Joe)
Not only a less than minimally educated person, but stupid and out of touch as well.
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Joined: Dec 2002
Posts: 25,933 Likes: 6
Campfire Ranger
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Campfire Ranger
Joined: Dec 2002
Posts: 25,933 Likes: 6 |
Ever seen any data giving the 308 and a 150 grain bullet 2650 fps and Bullseye being the shown powder? No. But the principal remains. All else being equal, faster powders will generate more pressure at a given velocity. Velocity can't be used to gauge pressure. Correct it’s not a gauge, just as your Hornady Round Nose bullets expanding primer pockets is not “a Gauge”. If you're using a load that's stretching the primers pockets first time out, you're over pressure. Believe it. Absolutely correct. But according to your criteria. It is still not a guage, as you have no idea what pressure was required to expand the primer pockets of this particular piece of brass. Proper use of a Chrony could have warned of excessive pressure/velocity, before you ruined your brass. And yes, I have ruined my share of brass. I have managed, while experimenting, to expand brass enough that it would not fit into the shell holder on my press. As mentioned, I swelled the primer pockets out of some .243 brass using a load that was listed as below maximum. I didn't check velocity. But I doubt if the velocity was excessive. The pressure in the cartridge was high because the long bearing surface of that particular bullet was creating much higher than typical drag as it passed down the barrel. That excessive drag could very well have caused velocities to be lower even though it pushed pressures higher. Chronographs don't measure pressure. That's it. That's all. Sorry B. It don't work that way. Area under the pressure curve is directly related to bullet energy, thus velocity. The two can not be separated. Buy a pressure trace and see for yourself if you refuse to believe those who have done the research. Yes, it is a matter of faith. have some!
People who choose to brew up their own storms bitch loudest about the rain.
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Joined: Jan 2005
Posts: 57,494
Campfire Kahuna
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Campfire Kahuna
Joined: Jan 2005
Posts: 57,494 |
That load could work well for some of the posters on the fire.
We can keep Larry Root and all his idiotic blabber and user names on here, but we can't get Ralph back..... Whiskey Tango Foxtrot, over....
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Joined: Apr 2005
Posts: 30,943 Likes: 1
Campfire 'Bwana
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Campfire 'Bwana
Joined: Apr 2005
Posts: 30,943 Likes: 1 |
Ever seen any data giving the 308 and a 150 grain bullet 2650 fps and Bullseye being the shown powder? No. But the principal remains. All else being equal, faster powders will generate more pressure at a given velocity. Velocity can't be used to gauge pressure. Correct it’s not a gauge, just as your Hornady Round Nose bullets expanding primer pockets is not “a Gauge”. If you're using a load that's stretching the primers pockets first time out, you're over pressure. Believe it. Absolutely correct. But according to your criteria. It is still not a guage, as you have no idea what pressure was required to expand the primer pockets of this particular piece of brass. Proper use of a Chrony could have warned of excessive pressure/velocity, before you ruined your brass. And yes, I have ruined my share of brass. I have managed, while experimenting, to expand brass enough that it would not fit into the shell holder on my press. As mentioned, I swelled the primer pockets out of some .243 brass using a load that was listed as below maximum. I didn't check velocity. But I doubt if the velocity was excessive. The pressure in the cartridge was high because the long bearing surface of that particular bullet was creating much higher than typical drag as it passed down the barrel. That excessive drag could very well have caused velocities to be lower even though it pushed pressures higher. Chronographs don't measure pressure. That's it. That's all. If you were using the proper burn rate powder, your velocity was higher as well
I got banned on another web site for a debate that happened on this site. That's a first
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Joined: Aug 2010
Posts: 48,111 Likes: 11
Campfire 'Bwana
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Campfire 'Bwana
Joined: Aug 2010
Posts: 48,111 Likes: 11 |
Too hot? Or just about right? Your opinion matters... Thanks Pretty cool trick. When a FC brass stamps "HORNADY".
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style. You want to see an animal drop right now? Shoot him in the ear hole. BSA MAGA
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Joined: Aug 2010
Posts: 48,111 Likes: 11
Campfire 'Bwana
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Campfire 'Bwana
Joined: Aug 2010
Posts: 48,111 Likes: 11 |
I'd keep adding more powder until the correct brass headstamp showed-up on the bolt face. LOL... ya got me. This is like the thread where a guy posted pictures of another mans buck and claims it as his.. Only more obvious. Kind of like the idiots that start at the max book loads and work up from there to "find pressure and rock on". Those guys are known for starting there and then adjusting seating depth to find accuracy too. Carry on though, is all I can say..
I try to stick with the basics, they do so well. Nothing fancy mind you, just plain jane will get it done with style. You want to see an animal drop right now? Shoot him in the ear hole. BSA MAGA
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Joined: Feb 2003
Posts: 10,385 Likes: 4
Campfire Outfitter
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Campfire Outfitter
Joined: Feb 2003
Posts: 10,385 Likes: 4 |
I have been banned from more gun forums for posting my overload work ups... than I have blown up guns. ~15 years ago there was a guy on Accurate Reloading forum that could calculate von mises stress in brass case heads. https://en.wikipedia.org/wiki/Von_Mises_yield_criterionHis name was "a$$ clown". When I overload a 308 case until extractor groove growth [mauser case head] Quickload would say ~72 kpsi That agreed with his prediction, as did 223 at a higher pressure.
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. -Ernest Hemingway The man who makes no mistakes does not usually make anything.-- Edward John Phelps
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