I have a 264 Win Mag Sense to and am developing loads for accuracy. As the 264 has ample case capacity and I generally like to have 90%+ fill, this would favor the slower powders. That said, I've tried some RL33 and noticed the heavy barrel is not after 1 firing on a cold barrel. Closely similar velocities with faster powders seem to put less heat in the barrel.
Q's: Assuming I find an accurate load with faster powders (IMR4350 is not bad), will the barrel life be better off with the faster powders or slower powder? I had thought that peak temp would be lower and favor the slow powder, but I'm having second thoughts on that theory.
Sorry for unclear post, darned auto spell checker. Rifle is Remington Sendero. Barrel is hot after 1 round when shooting RL33 with 130gr A-Max with 72.5gr. No pressure signs.
I'm glad I'm over those days!
It would stand to reason that if you load a larger charge of slower powder you will be subjecting the barrel to a longer intense burn period. Hence, the barrel heats up faster and the throat would erode faster.
But, I could be wrong, I was once before.
For one thing I never thought of 4350 as being fast. But I can see the OPs point. Fast powder has a fast pressure peak. Higher pressure=higher temp.
I agree that normally 4350 is not regarded as fast, unless you load a 264 Win Mag.... Typical powders for the 264 are 4831 and 7828, H1000 and the old H870. I'm thinking now that the quicker flash provides less time to heat, so while hotter, the faster powders reduce conduction time and there's likely less difference in the flame temperatures.
It’s probably not enough of a difference to matter in terms of round count/barrel life. Also barrels are cheap to replace!
For one thing I never thought of 4350 as being fast. But I can see the OPs point. Fast powder has a fast pressure peak. Higher pressure=higher temp.
No, not nearly correct. The more powder burned, the higher the temperature--especially with double-based powders, though the temp difference isn't all that much compared to single-based powders.
It’s probably not enough of a difference to matter in terms of round count/barrel life. Also barrels are cheap to replace!
OK there Diamond Jim.
About half my rifles are magnums and the other half is not.After scoping the barrels out,it looks like you start seeing erosion with magnum cartridges in few as a hundred rounds when your burning about 70-80grs or so of powder.My non-magnum rifles burning 45-60grs of powder with several hundred rounds through them don't show any erosion.So it seems to be like a cutting torch,burning large amounts of powder is going to get the barrel hotter and starts to slowly burn.Add that with multiple firings without cooling is going to speed up the barrel burn.Magnums are great,I really like them.Work up a load for them and shoot them a lot less and they will last a long time.Get a 308 or a 30-06 and shoot them more while your saving the barrels on your magnums.
There is one heck of a difference in the Heat Index between various powders. This is evidenced by how difficult some are to clean as the carbon gets cooked on to a much higher degree than others.
I tried to copy and post the Heat Index chart where they give the Relative Heat Index of all powders listed by the coolest to the hottest.
I know RL 33 is a very slow burning powder, but 72.5 grains of anything in a 264 is a boatload. And Alliant doesn't even list it in 264 charts, or the ones I have.
Loading a 264 off Hodgdon charts with their powder plus IMR & Winchester shows a max charge of 67 or 8 grains. with the slowest they offer.
Now this doesn't answer which powder is hotter, but 72.5 grains in a 264 might be a whole different source of heat.
Am I way off base here? Missing something?
The RL33 data i have i obtained from what sounded like a knowledgeable 264 shooter. His pet load in 264 WM was 77.0gr with a Berger 140 VLD as I recall. I started low and have been up to 77.0 gr and primers were starting to flatten, but the firing pin dimple still looked good. No extraction problems or case splits. I generally never load anything near max as accuracy generally is not there.
Accuracy wasn't there at 77.0gr, and I had some 3-shot groups of 0.146" at 100yd with 72.5gr in 40F weather with a 130. My Sendero with 1:9 can't handle a 140 boat tail. Remington flat base 140's are ok, but 120-130gr are more accurate.
I am using Redding neck bushing dies and turn/ream every firing to remove brass flow, true the necks, and maintain constant neck thickness and concentricity. About 0.001" flows around 0.040" length on the end of the neck into the I/D, and 0.0008" down the rest of the neck O/D. I bushing size necks to clean up the I/D with a std reamer, pilot on a custom size pilot I hard turned, and neck turn with the same setup every firing, then final bushing size for 0.002" interference for neck tension.
Agree that this is a lot of powder. From others using it and older reloading books, it appears that it's close to H870 in burn rate. Since Warner weather has come on, the RL33 has not been as stable, and I've noticed the great amount of barrel heat, hence my post. Some had raved of it in 264AM but it looks like it might not be there for me. I have probably 200 rds through this gun and would prefer not to rebarell it soon, even though I'd like a 1:8 twist.
Thanks for the opinions, good dialogue.
Have you tried H1000 or Retumbo? Those powders work very well in the 264Win with 130+ gr bullets.
I know RL 33 is a very slow burning powder, but 72.5 grains of anything in a 264 is a boatload. And Alliant doesn't even list it in 264 charts, or the ones I have.
Loading a 264 off Hodgdon charts with their powder plus IMR & Winchester shows a max charge of 67 or 8 grains. with the slowest they offer.
Now this doesn't answer which powder is hotter, but 72.5 grains in a 264 might be a whole different source of heat.
Am I way off base here? Missing something?
I've loaded 77.0 gr of US 869 in my .264 Win Mag. Goes about 3,100 fps with a 140-143 gr bullet.
On a side note, I know W-748 was developed with a "low flame temperature" - whatever that means. Burns cooler than comparable speed powders?
Very interesting. Slower powders & data changing rapidly these days. AAbout like buying the latest electronics & by the time you get it home & set up, something newer & better comes along.
I thought the 264 had been satisfied with newer powders from the last decade. Looks like it ain't over yet.
But back to heat, 70+ grains in that bore size has to be a heat generator in it self, not to mention ever ending shortages. Think I'd stay a bit more conventional. Or is that just hiding your head in the sand?
Have you tried H1000 or Retumbo? Those powders work very well in the 264Win with 130+ gr bullets.
Retumbo does 3225 from my 26” M70 with 140 Accubonds. 33 was a bit faster just not quite as accurate overall. I don’t think you’re on the wrong track with 33 or Retumbo or Magnum or whichever slow burner you can get in there. The 264 is a hot rod so taking it easy on the number of rounds fired helps but it’s never going to be easy on rifling.
Thanks guys for input. I'm trying some Ramshot Magnum and will plan to pick up some Retumbo to try as it's one that's been floated by several guys. Keep ticking at it as it shows signs of a rack driver here and there. 264 AM is a lot more fun than just following the Creedmore path. 😊
Many of the ball powders burn cooler than stick type. Many of these are slower burning powders so it is burn temperature more than burn rate. Magnum may be in this cooler burning category. One theory and it may only be a theory is the ball powders are less abrasive than stick powders due to the shape of the powder grains. This came from testing in machine guns with high round counts of over 10,000 in some of the tests.
Anyway 869 may be cooler burning but is less temperature stable than Magnum so hope it pans out for you.
Just got the Ramshot Magnum powder this afternoon. Looks like H380 but must be slower yet. Anyone know if this is a rebranded Hodgen powder of some sort aka H414 W760? I'll still use the Ramshot data, just curious.
I don’t believe so. I haven’t used a pile of it but it’s much like the old H870 but cleaner burning once you’re at pressure.
Ive shot a 264 for several years. Imr7828 is your friend. Something around 66.5g with a 130 in win brass cci 250 should be about 3350 fps.
Bb
That's interesting.
Hodgdon lists 60.1 grains of 7828 as maximum with the 130-grain Nosler AccuBond, for 3053 fps from the now-standard SAAMI 24" test barrel at 63,200 PSI. That's using Winchester brass and the Winchester LR Magnum primer. A 26" barrel would probably get 3100 or a little more.
That's interesting.
Hodgdon lists 60.1 grains of 7828 as maximum with the 130-grain Nosler AccuBond, for 3053 fps from the now-standard SAAMI 24" test barrel at 63,200 PSI. That's using Winchester brass and the Winchester LR Magnum primer. A 26" barrel would probably get 3100 or a little more.
John, weren’t you the one that’s used Magnum and 140’s for a few 264’s and said 3150-3200 wasn’t any big trick? I could’ve sworn that’s where I got the idea.
For one thing I never thought of 4350 as being fast. But I can see the OPs point. Fast powder has a fast pressure peak. Higher pressure=higher temp.
No, not nearly correct. The more powder burned, the higher the temperature--especially with double-based powders, though the temp difference isn't all that much compared to single-based powders.
Seems like there might be more data buried in the lab bomb test data (depending on what they collect).
It's just thermodynamics and the ideal gas law PV=nRT
It's really about heat calories released from the powder(which is tied to powder burned) and how much energy is in the powder. That might be something captured in the burn rate bomb tests...
The other factor is heat transmission. Different alloys/grades transmit heat differently.
Fast transmission is good because it means the barrel cools quickly...
You might have heat sensitive hands too...
30 years ago Bart Bobbitt came up with formula for barrel life.
https://yarchive.net/gun/barrel/bar...l.,3000%20rounds%20of%20good%20accuracy.But when a top level competitor thinks a barrel is shot, and when a putz like me thinks a barrel is shot, are too different amounts of erosion.
There is one heck of a difference in the Heat Index between various powders. This is evidenced by how difficult some are to clean as the carbon gets cooked on to a much higher degree than others.
I tried to copy and post the Heat Index chart where they give the Relative Heat Index of all powders listed by the coolest to the hottest.
keith, that makes a lot of sense. It doesn't look like your chart came through, but do you have a link to it online? I'd like to take a look.
I've shot 3 shot groups of H1000 and N570 through my 30-28 Nosler at basically the same rate of fire and I can tell you for sure the barrel is hotter to the touch after shooting N570. Personally the more I use H1000 in magnums the more of a fan I am it's very temp stable also.
Seems like there might be more data buried in the lab bomb test data (depending on what they collect).
It's just thermodynamics and the ideal gas law PV=nRT
It's really about heat calories released from the powder(which is tied to powder burned) and how much energy is in the powder. That might be something captured in the burn rate bomb tests...
The other factor is heat transmission. Different alloys/grades transmit heat differently.
Fast transmission is good because it means the barrel cools quickly...
You might have heat sensitive hands too...
That is it in a nutshell. It's all about heat. Not just heat released, but heat absorbed by the barrel throat. More powder --> more heat. The amount of powder obviously effects the amount of heat, but also the heat content of the powder has an effect. Joe Hendricks has provided a great illustration of this with his use of H1000 in the .243 Winchester. You can see the heat content for many powders in the Excel file found at
https://www.accurateshooter.com/technical-articles/excel-formula-predicts-useful-barrel-life/ Those numbers are taken from Quickload.
A factor many overlook is the bullet. Again, heat absorption is key. The heavier the bullet the longer it takes to engrave in the throat. The longer this dwell time, the more heat is absorbed. That is why loads that have more powder but feature a lighter bullet will usually wear out the barrel at a slower rate. And it's the key to Danzac and Moly. These bullet lubricants allow the bullet to engrave faster resulting in less dwell time in the throat and less heat being absorbed by the barrel.
I've shot 3 shot groups of H1000 and N570 through my 30-28 Nosler at basically the same rate of fire and I can tell you for sure the barrel is hotter to the touch after shooting N570. Personally the more I use H1000 in magnums the more of a fan I am it's very temp stable also.
Makes sense. N570 has a heat content of 4000 kJ/kg and H1000 has a heat content of 3630 kJ/kg. You'll get better barrel life from H1000.
Finally was able to get out to the range and try the Ramshot in 120 and 130gr Hornady ELDs. The 1:9 twist seems to favor 120's over 130's and this was no different. The Ramshot is WAY cooler than RL33; I shot both allowing cool time between shots. On a cold barrel, RL33 makes the barrel hot to touch. Can shoot 3 RDA of Ramshot before it's this hot. Group size with the Ramshot 120's was in the 0.75" for 4 shots. I'll have to work more before judgement, but it's definitely cooler than RL33. Had great results with RL19 & 120gr, 3 shots touching for 1 tear, 1 flier 3/8" away.
"3 shots touching for 1 tear, 1 flier 3/8" away." Wish my flyers were only 3/8" away!
I will say that when you work up reduced loads using fast burning powders, especially pistol powders, that as the charge goes down, the heat goes down. It isn't a matter of pressure, because I've got a 17 FB load using TiteGroup that runs what seems to be very close to full pressure, and I can fire 3 times the rounds that I can with "standard" powders before the barrel gets hot.
I've also noticed that single base powders in full charges generate less heat than those using double base powders. And that cases full of powder warm up a barrel faster than cases with less fill. Seems like less powder would equal less barrel erosion, since erosion is a product of heat, but I have never been able to discern how much it matters. Not enough, I think, moving between 90% case fill and 105% case fill.
Seems like there might be more data buried in the lab bomb test data (depending on what they collect).
It's just thermodynamics and the ideal gas law PV=nRT
It's really about heat calories released from the powder(which is tied to powder burned) and how much energy is in the powder. That might be something captured in the burn rate bomb tests...
The other factor is heat transmission. Different alloys/grades transmit heat differently.
Fast transmission is good because it means the barrel cools quickly...
You might have heat sensitive hands too...
That is it in a nutshell. It's all about heat. Not just heat released, but heat absorbed by the barrel throat. More powder --> more heat. The amount of powder obviously effects the amount of heat, but also the heat content of the powder has an effect. Joe Hendricks has provided a great illustration of this with his use of H1000 in the .243 Winchester. You can see the heat content for many powders in the Excel file found at
https://www.accurateshooter.com/technical-articles/excel-formula-predicts-useful-barrel-life/ Those numbers are taken from Quickload.
A factor many overlook is the bullet. Again, heat absorption is key. The heavier the bullet the longer it takes to engrave in the throat. The longer this dwell time, the more heat is absorbed. That is why loads that have more powder but feature a lighter bullet will usually wear out the barrel at a slower rate. And it's the key to Danzac and Moly. These bullet lubricants allow the bullet to engrave faster resulting in less dwell time in the throat and less heat being absorbed by the barrel.
Didn't see your response Tyrone until today...
Good point on bullet weight. But don't forget monolith bullets. They will have a slightly different absorption rate..
Good point on bullet weight. But don't forget monolith bullets. They will have a slightly different absorption rate..
I don't use monos. I imagine they are harder on barrels?
Steel jackets are harder on barrels. They are harder to engrave and they don't upset as well as copper jackets, allowing for more gas cutting.
I was thinking of Copper monoliths like the GMX.
But solid copper should be "stiffer" th a copper around a lead core...
But their relative specific heat capacities. I would have to look those up...
Yeesh,
Yeah a steal jacket could be tough on the lands...
About "dwell" time, if you seat your bullets deeper when they hit the rifling they will be going faster so dwell time will be reduced. Is it possible seating bullets deeper will help barrel life?
I think at least based on the experience so far with my 264 WM, it looks like total powder burned is the first factor, then the second is burn rate of the powder, or time for the heat to conduct into the barrel. These are probably not unique, and they are intuitive, but I was thinking that maybe peak temp of a fast burning powder was more of a factor than it appears to be. Total heat and time for conduction appear to be the drivers that I see.
There is a significant difference in heat between Ramshot and RL33, but RL33 is still slower, and I'm wondering if at lower pressure the RL33 consists that much slower than Ramshot. I'd still like to try Retumbo but can't find any around here for sale or through Midway.
I have a 264 Win Mag Sense to and am developing loads for accuracy. As the 264 has ample case capacity and I generally like to have 90%+ fill, this would favor the slower powders. That said, I've tried some RL33 and noticed the heavy barrel is not after 1 firing on a cold barrel. Closely similar velocities with faster powders seem to put less heat in the barrel.
Q's: Assuming I find an accurate load with faster powders (IMR4350 is not bad), will the barrel life be better off with the faster powders or slower powder? I had thought that peak temp would be lower and favor the slow powder, but I'm having second thoughts on that theory.
The first gunsmith I used for a re-barrel had a dislike for any powders slower than 4350. He believed that slower powders eroded throats faster than 4350 and challenged whether any real benefit existed from that opinion. That was several decades ago now and I for one, cannot prove him wrong.
RL-33 is different than many powders. It has a longer burning curve like RL-17. Perhaps that is where some of the extra heat is coming from.
From my documents file:
RL-33 is only the second of a line of unique powders offered by Alliant. Borrowed this line from an ad: "New Reloder 33 Delivers More Speed in Big Magnums Now Alliant is introducing a new powder, Reloder 33, that uses the same kernel-impregnation technology first pioneered in Reloder 17. Alliant Reloder 33 is a new powder created by Rheinmetall Nitrochemie.
Be careful trying a bunch of powders and bullets. It won't be long before the barrel is shot out. I know I did it to a 257 weatherby. Learned plenty and the second barrel only shoots one bullet and one powder. Incidentally the powder is RL-33.
Heat values from "BarrelLifeUpdate.xls"
Accurate No.1680 => 4018 Hodgdon Benchmark=> 3900 IMR 3031 => 3880 Vihtavuori 20N29 => 3580
Accurate No.2230 => 3710 Hodgdon BL-C2 => 3990 IMR 4064 => 3880 Vihtavuori 24N41 => 3785
Accurate No.2460 => 3690 Hodgdon H110 => 4110 Hodgdon H322 => 4000 IMR 4198 => 3910 Vihtavuori N120 => 3680
Accurate No.2520 => 3700 Hodgdon H335 => 3980 IMR 4227 => 4040 Vihtavuori N130 => 3770
Accurate No.2700 => 3545 Hodgdon H380 => 3970 IMR 4320 => 3890 Vihtavuori N133 => 3630
Accurate No.8700 => 3460 Hodgdon H414 => 3960 IMR 4350 => 3900 Vihtavuori N135 => 3590
Accurate XMR 2015 => 3754 Hodgdon H4198 => 3860 IMR 4831 => 3720 Vihtavuori N140 => 3720
Accurate XMR 2495 => 3810 Hodgdon H4350 => 3990 IMR 4895 => 3890 Vihtavuori N150 => 3780
Accurate XMR 3100 => 3550 Hodgdon H4831 SC => 3870 IMR 7828 => 3850 Vihtavuori N160 => 3620
Accurate XMR 4064 => 3700 Hodgdon H4895 => 3930 Norma 200 => 3850 Vihtavuori N165 => 3500
Accurate XMR 4350 => 3790 Hodgdon H1000 => 3630 Norma 201 => 3980 Vihtavuori N170 => 3700
Alliant Reloder- 7 => 3910 Hodgdon 50BMG => 4010 Norma 204 => 3950 Vihtavuori N540 => 4100
Alliant Reloder-10x => 4000 Hodgdon H870 => 3810 Norma MRP => 4020 Vihtavuori N550 => 4050
Alliant Reloder-12 => 3830 Hodgdon VARGET => 4040 Winchester 748 => 3840 Vihtavuori N560 => 4020
Alliant Reloder-15 => 3990 Ramshot BigGame => 3920 Winchester 760 => 3880
Alliant Reloder-19 => 3980 Ramshot Enforcer => 4005 WinchesterWXR => 3980
Alliant Reloder-22 => 3990 Ramshot Magnum => 3775 Winchester 296 => 4300
Alliant Reloder-25 => 3810 RamshotTAC => 3950
Alliant AR Comp => 3740 Ramshot X-Terminator => 3950
Tyrone, thanks for the Excel spreadsheet and the powder heat values above. In doing some crunching, I've
Powder Powder Gr Barrel Life Bullet WT Velocity
H870 72.5 55K 821 130 3200
H4831SC 68.5 55K 850 95 3550
Magnum 65.8 55K 1044 130 3100
IMR4350 58.2 55K 1133 130 3100
IMR7828 62.2 55K 1059 130 3100
IMR7828 70.4 55K 826 95 3550
H4350 62.5 55K 826 95 3550
RL22 58.1 55K 1015 140 3000
Magnum 64.9 55K 1073 140 3000
Oops, posted the above accidentally while trying to get formatting aligned. Essentially, it seems that it's a balance between heat and powder volume. I ran both fast and slow powders at the same velocities and there seems to be little difference in calculated barrel life. The RL33 remains a mystery as to why it generates so much heat vs say Ramshot Magnum. RL33 is still slower than Magnum, and with 5gr of powder difference it's a huge difference in barrel heat. All I can attribute this to is time - that the RL33 burns so slow that there's more opportunity for heat conduction to occur. RL33 shoots very accurately, but I'm looking for an alternative which can produce the accuracy. I always let the barrel cool and never shoot the gun if it's warm to touch, but according to the Excel document, this doesn't look like it makes much of a difference between powders, and that the 264 is simply doomed. If I find that I've shot out the barrel, then a 1:8 twist will go on. Interesting stuff, thanks everyone!
Probably has some/more nitroglycerin than RS Magnum.