Best Powders for Heavy Rifle Calibers out of Short Barrel

[5whiskey]

Just that. If one were to reload for, say, a short barrelled (say 20") 8x57 or 7.62x54 what powder would be most efficient in terms of velocity? I would probably shoot light-medium weight for caliber projectiles. I'm thinking a fast for cartridge powder. Anyone with experience to weigh in (Looking at you Uncle Nick lol)?

[the Black Spot]

Varget or 4895

[Dano4734]

Imr4198

[firewrench044]

150 Gr bullet IMR 4895
168 Gr bullet VARGET
175 Gr bullet IMR 4064

[Charlie98]

I had sort of the same problem with my .348WCF. Load data for the typical 24" rifle barrel called for H4831, which I tried. Lots of muzzle blast and mediocre velocity out of my 20" carbine barrel. I switched to IMR3031 and haven't looked back... less powder (by weight,) less blast, more velocity, better accuracy (which is arbitrary.)

Interestingly, I found the very same thing in .308 with my 16" barreled M1a. I started with IMR4895, which works... but is more suited to the standard barrel length of 22". I switched to IMR3031 there, too, and found all of the above, again.

[FrankenMauser]

All of my initial suggestions are in the previous posts.

Some additional options:
Reloder 17
CFE223
VV N550
W760
H414
W748
Ramshot Big Game


However, you don't really need a 'fast' powder for a short barrel. If you're running something that's leaving a bunch of unburned powder in the bore, it's just the wrong powder for the application or not a hot enough powder charge. (Or contaminated powder.)

8x57mm, especially when using SAAMI-conforming reloading data, is a common victim of light charges that are inappropriate for the load and powder. Limiting chamber pressure to 35,000 psi keeps a lot of rifle powders from achieving full burn - whether in a 16" barrel or 26" barrel.
Whose data are you using? And what pressure levels do you intend to load to? (SAAMI? Or CIP [full pressure]?)

[Unclenick]

Well, let's be careful not to mix apples and oranges. Looking at Hodgdon's data for 348 Win, it shows lower velocity and pressure for H4831 with a 200-grain bullet and a large compressed charge than for a maximum load of 3031 because H4831 is really too slow burning for that combination in the first place. Hence the velocity advantage that may be gleaned from 3031, but it's not due to barrel length. It would be true with a 26" barrel, too. Hodgdon's 250-grain bullet data makes H4831 look better, but the bullet is a Barnes solid, and the higher start pressure is a significant factor in getting H4831 to burn, especially at 348 Win pressures. A 250-grain cup and core would still not work as well with H4831.

In 308 Winchester, Hodgdon data shows you should not, at the same peak pressure, be able to beat 4895 for velocity with 3031 until you are using bullets 125 grains or less for their 24" test barrel. For a 16" barrel, velocity differences are not too far apart even with 150-grain bullets, but 4895 should still win. If you are seeing a velocity advantage to 3031 there, the peak pressure is higher.

As a general rule of thumb, the powder that produces the highest velocity with a 24" standard test barrel will still produce the highest velocity with a 16" barrel, though the difference between faster and slower powders will have diminished at that length. Which powder produces the greatest velocity will start to change order among some choices when you get down to SSB lengths. Mostly, though, you are going to need to be under 12-inch barrel length for that to begin to get noticeable. Maybe 9 inches or so.

The main advantage to a faster powder in a short barrel is the flash and muzzle blast reduction. The military accepts higher pressure in the M855A1 Enhanced Performance cartridge in order to use a faster powder to help reduce those factors in the M4's barrels and the even shorter spec ops weapons. There is a trade-off, though, and they've reported problems with faster throat wear.


5whiskey,

Going with a fast-for-caliber powder will cut the muzzle flash and blast, but will cost you a little velocity when the peak pressures match. If you are going for light or moderate loads, though, it can be just the ticket and will perform better in terms of velocity consistency and usually in terms of fouling, too, when the pressures are on the low side.

Slow powders get their velocity advantage from keeping pressure up in the barrel past the peak. As a barrel gets shorter, that has less advantage to bullet velocity because there is less length past the peak in which post-peak barrel pressure can further accelerate the bullet. Slow powders also often peak when the bullet is a little bit further down the barrel than where faster powder peaks, and that affects the point at which a faster powder starts to get more velocity than a slow one does. But those differences are on the order of half an inch to an inch, typically, so you can't expect to get fast powders to produce more velocity than slow ones until that short difference become significant to the total bullet travel (the length from the muzzle to the position of the base of the bullet at the moment the gun starts to fire).

[5whiskey]

8x57mm, especially when using SAAMI-conforming reloading data, is a common victim of light charges that are inappropriate for the load and powder. Limiting chamber pressure to 35,000 psi keeps a lot of rifle powders from achieving full burn - whether in a 16" barrel or 26" barrel.

Oh yes I am aware of this. I did quite a bit of legwork to come up with H414/Win760 recipes in 8x57 that was above the SAAMI limit of 35k. I started at a perceived very safe 49 grains of H414. There was, in fact, very erratic accuracy and a high SD. I settled on 52.5 gns under a 180gn projectile that, to the best of my ability to reason through it (appropriate velocity, comparing reloading data for similar cases, no signs of pressure, etc.), should be right around 45k or so. Accuracy is pretty darn good (hindered by my eyes and iron sights) with a 10 round group at 100 yards filling up circle a tad over 2 inches. Pressure should be a happy medium between CIP and SAAMI and plenty safe for many rounds through a surplus mauser in good shape and a .323 bore. If you are asking my references... Hodgdon, an older Lyman manual borrowed from a friend (maybe 47th edition?), some Quickload data posted on an old thread, and Modern Reloading... but no one had my current load listed.

Back to the topic at hand, I haven't loaded anything for the heavy caliber carbine barrel yet. It may be months or even a year or more. Just fishing for info really.

UncleNick muzzle blast is a consideration as well. Fireballs are kind of cool... until you have range sessions shooting more than 5 rounds. I thought there might be some potential for specific powders being better for velocity out of shorter barrels, but it does make sense that at best the optimum powders for the caliber are just less optimum with the shorter barrel.

[gwpercle]

RX7
3031
4895
Varget
These and several more will all do fine.
Gary

[Metal god]

I have been thinking about this very issue for a few weeks now when it comes to my 20" RPR in 308 . I want to shoot 1k yards with this rifle and have chosen a heavy for cartridge bullet . The 195gr ELD and 200.20x Berger with a slow burning powder N-550 which is the IMR 4350 burn rate area .

That Berger bullet has a BC of .640 . When I plug in the data into there ballistic calculator . If I can get that bullet to 2300fps from a 20" barrel they say I will have the full .640 bc working for me , 1k should not be a problem and maybe 1200yds is doable .

Anyone want to run that combo through QL
308 Win
20" barrel
1-10 twist
N-550 powder somewhere around 44gr , not sure ( data seems to be 38gr thru 45gr-ish still trying to confirm start and max loads for this bullet
200.2gr bullet
1.496" long
BC .640
Case volume 55.53gr
COAL 3.030
.030 off the lands
Fed match primer

[FrankenMauser]

QL thinks it's possible.
Berger Hybrid used for the prediction, at 1.500" bullet length.

Full size
Half size
I provided two links, because the original image was displaying twice as large as it should have on my computer and phone. I didn't want to unintentionally post a ginormous photo in the thread, or something so large that it was unreadable. So, there's a half-size version, as well.

Primer, jump, BC, and twist don't matter in QL. ...And my version of QuickTarget isn't working.

[Metal god]

Thanks Franken Mauser , Those numbers are pretty much what I thought they would be . Nice to have some conformation on what my own research came up with .

[disseminator]

In general, if you just go with heavy for caliber bullets you should see minimal performance loss with a shorter barrel since they use less powder than a lighter bullet in the same cartridge would.

[44 AMP]

Nothing burning 40+ grains of powder from a 20" or shorter barrel is going to have "reduced" flash and blast.

Faster powder do have a bit less bark from short barrels, compared to slower powders in the same short barrels, but that's because a smaller portion of the powder is burning outside the muzzle.

Try a variety of combinations, but don't look for the one with the highest velocity or the lowest muzzle blast alone, look for the one that is the most accurate in your gun, with you shooting it. If you find all three in one load, rejoice. If you don't, what is actually the most important? TO me, its hitting what I'm aiming at.

[5whiskey]

TO me, its hitting what I'm aiming at.

This is usually my top priority! With that being said, I'm pretty good with iron sights but I'm not THAT good. 2moa is about my best these days, as the FSP gets more and more difficult to focus on the older I get! In a scoped rifle on bipods, I'm looking for that 1/2moa group. With original mausers and mosins, I'm not sure that I could tell minute differences in powder "accuracy."

BTW the question refers to a Mosin M44 I may eventually end up reloading for. I guess a 20" barrel isn't THAT short, but much more so than the standard rifle. Hence the question, I want to pick the powder most suited for the application.

[FrankenMauser]

BTW the question refers to a Mosin M44 I may eventually end up reloading for. I guess a 20" barrel isn't THAT short, but much more so than the standard rifle. Hence the question, I want to pick the powder most suited for the application.

IMR4064 (or 4166) or one of the 4350s will be your friend. I found AA4350 to be a better performer in my rifles, but the IMR and Hodgdon versions have much more data available.

Though at the opposite end of the spectrum when it comes to the topic at hand, I also had excellent performance with AA3100. But, as with all reloading components that I find to work well, I believe it has been discontinued.

[Charlie98]

BTW the question refers to a Mosin M44 I may eventually end up reloading for.

Interesting you mention that... I was shooting indoors with my Socom16 and some surplus M80... indoors with the muzzle brake the Socom is pretty loud. Dude slides up next to me... with a M44 carbine and some Silver Bear ammo. Lord in Heaven! I'm tough, but I had to step back out of my booth when he was firing that thing.

Well, let's be careful not to mix apples and oranges. Looking at Hodgdon's data for 348 Win, it shows lower velocity and pressure for H4831 with a 200-grain bullet and a large compressed charge than for a maximum load of 3031 because H4831 is really too slow burning for that combination in the first place. Hence the velocity advantage that may be gleaned from 3031, but it's not due to barrel length. It would be true with a 26" barrel, too. Hodgdon's 250-grain bullet data makes H4831 look better, but the bullet is a Barnes solid, and the higher start pressure is a significant factor in getting H4831 to burn, especially at 348 Win pressures. A 250-grain cup and core would still not work as well with H4831.

In 308 Winchester, Hodgdon data shows you should not, at the same peak pressure, be able to beat 4895 for velocity with 3031 until you are using bullets 125 grains or less for their 24" test barrel. For a 16" barrel, velocity differences are not too far apart even with 150-grain bullets, but 4895 should still win. If you are seeing a velocity advantage to 3031 there, the peak pressure is higher.

As a general rule of thumb, the powder that produces the highest velocity with a 24" standard test barrel will still produce the highest velocity with a 16" barrel, though the difference between faster and slower powders will have diminished at that length. Which powder produces the greatest velocity will start to change order among some choices when you get down to SSB lengths. Mostly, though, you are going to need to be under 12-inch barrel length for that to begin to get noticeable. Maybe 9 inches or so.

The main advantage to a faster powder in a short barrel is the flash and muzzle blast reduction. The military accepts higher pressure in the M855A1 Enhanced Performance cartridge in order to use a faster powder to help reduce those factors in the M4's barrels and the even shorter spec ops weapons. There is a trade-off, though, and they've reported problems with faster throat wear.

No, I understand what you are saying. The whole episode with the .348 and slow powders changed the way I thought about powder selection in rifle cartridges. What blows my mind is something like the 6.5CM... where, even with the smaller bore, very slow powders rule the day.

IMR3031 in the .308. Because of the M1a's operating system, I was a little more cautious ramping up powder charges, particularly with slower powders like IMR4895 and IMR4064... your slower powders/longer peak pressure comment is correct. After reading quite a bit about it, I decided IMR3031 was probably the better powder in the shorter barrel, but as you mention, pressure with IMR3031 ramps up pretty quickly.

[FrankenMauser]

What blows my mind is something like the 6.5CM... where, even with the smaller bore, very slow powders rule the day.

General rule for any given basic cartridge family:
Smaller bore = slower powder.
Larger bore = faster powder.

A good example would be the JDJ cartridges based on .444 Marlin. With the .309 JDJ, you run typical '308 powders'. But step up to the original cartridge, and it gets filled with some of the fastest rifle powders available - powders that, in some applications, have burn rates faster than some 'magnum' handgun powders.

[Charlie98]

General rule for any given basic cartridge family:
Smaller bore = slower powder.
Larger bore = faster powder.

A good example would be the JDJ cartridges based on .444 Marlin. With the .309 JDJ, you run typical '308 powders'. But step up to the original cartridge, and it gets filled with some of the fastest rifle powders available - powders that, in some applications, have burn rates faster than some 'magnum' handgun powders.

Quite true... and it took me a while to figure that out. I used to use much slower powders with the .45-70, for example, nowadays the slowest powder I use there is IMR3031!

[44 AMP]

General rule for any given basic cartridge family:
Smaller bore = slower powder.
Larger bore = faster powder.

I think you need to modify your general rule a bit. It's not just the bore size, its the bore size to case powder capacity ratio that determines whether slower or faster powders are useful.

Slower powders work better /best when case bodies are "overbore", meaning considerably larger than the bore size. Straight wall cases, are not over bore, and work best with faster or medium rate powders, poorly with slow powders.

If you want some examples of the extremes, here's a few
.22 Hornet vs .22-250
.25-20 vs .25-06
.30-30 vs .300 Weatherby

all these pairs, and many I didn't mention have the same bore size, but the case capacity is hugely different. Pressure limits for various individual cartridges play a part, as well, but in general, its case volume to bore size ratio that determines if slower powders will perform properly.

Nearly all pistol rounds are straight(ish) walled cases, not much, if any over bore size. The slowest pistol powders are the very fastest rifle powders, and aren't suited when case capacity is too small, or too large.

Example, 2400, one of the slowest pistol powders, not suited to 9mm Luger or smaller cases, works in .357Mag and larger cases, works in .22 Hornet, .30 Carbine, and other small rifle cases, not even a good choice to use in a .300 Magnum.

[FrankenMauser]

I think you need to modify your general rule a bit. It's not just the bore size, its the bore size to case powder capacity ratio that determines whether slower or faster powders are useful.

Agreed. But I don't believe I need to modify the statement.
I believe my limitation of "...any given basic cartridge family" covers that.
I went with that limitation specifically to avoid getting into expansion ratios. Although it is the driving factor, I only felt like touching on the topic, rather than diving in.

[Archie]

If one seeks the highest possible muzzle velocity from any rifle, powder burn rate is determined by bullet weight (heavier bullet weight demands slower burning powder). The fastest muzzle velocity for a given bullet weight will be the fastest muzzle velocity in any length barrel. (Short barrels will be slower, but so will any other load.)

If one seeks the highest possible muzzle velocity in relation to the amount of powder used, use the fastest powder consistent with safe pressure.

So it depends on what is desired. For maximum performance, match the bullet weight to the burn rate. Heavier bullets require slower powder. One never achieves higher velocity with the theory of matching powder rate to barrel length.