Faster Burning Powder for Shorter Barrel?

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3006loader

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Basically what I am wondering is can you get the same velocities as a longer barrel out of a shorter barrel by using a faster burning powder? For .308 Win, out of a 24" barrel, a 180 grain bullet will move at 2550 fps. Let say (for the sake of not knowing what actual powder was used) 49 grains of H414 was used to get this velocity. If you were to cut that barrel down to 16" you would get a velocity of 2370 fps with the same 180 grain bullet. If you were to use a faster burning powder like H4895 in the 16" barrel, would you be able to bring the velocity back up to 2550 fps? If so, would this be dangerous, pressure wise?
 
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"can you get the same velocities as a longer barrel out of a shorter barrel by using a faster burning powder?"

Simple answer: yes. But faster burning often results in higher pressures.

So until you have much more experience, just stick to the published loads, and worry about new recipes later.

You might call Hodgdon about the H4895 question - I think the techs are often willing to help.
 
The powder that produces the highest velocities in a longer barrel will be the powder that gets the highest velocities in a shorter barrel.
 
would this be dangerous, pressure wise?
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Short answer, yes.

The highest velocity will be from a load that uses the most powder to give the maximum allowable pressure. That is pretty much the working definition of a "slow" powder, a high charge weight ratio.
 
The powder that produces the highest velocities in a longer barrel will be the powder that gets the highest velocities in a shorter barrel.
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Nope. As long as the peak pressure is safe and the total pressure is safe, you can get more velocity with a faster powder than a slower powder in a shorter barrel.

When looking at pressure, in an expanding chamber or vessel, we have the peak pressure and the average pressure. If a barrel is short with a slow powder it certainly can have a lower velocity as compared to a fast powder still within the safety limits.

In general, you want the powder to have stopped burning (generating gas volume) just prior to the bullet leaving the barrel. That produces the most efficient propulsion. With short barrels, many people use powders that are too slow which can reduce barrel life and won't be as accurate either.

But you still want to be using powders and recipes that are published. If velocity is the primary desire, drop to 135s or so and go with the faster powders.
 
Hodgdon's website has load data for a 180 grain bullet using H4895 out of a 24"rifle and the max charge lists a velocity of 2595. I'm going to guess that using their data there is no way to get a 16" barrel to get 2550 FPS using anything remotely considered a safe load.

I'm sure it would possible to reach that velocity but you will be exceeding SAAMI limits.

30.06's 180 grain H4895 load data has a max charge with a velocity of 2,638 and even a couple other powders with velocities pushing 2800. If 2550 out of a 16" barrel is your goal 30.06 seems like a more logical cartridge.
 
Nope. As long as the peak pressure is safe and the total pressure is safe, you can get more velocity with a faster powder than a slower powder in a shorter barrel.
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This has been proven false many times, at least with rifles. There may be some truth when you start talking about 6" or shorter handgun barrels. Even the slowest powders completely burn within just a few inches, no more than 8-10", fast powders may burn in 6-8". All barrel length does is give the pressure longer to work on the bullet. Speeds from shorter barrels that I've tested have been slower, but the powder that gave me the best speeds from a 24" barrel was always the fastest from an 18" barrel.

Lots of guys shooting rifle cartridges from Contender pistols have found the same.
 
You are entitled to your opinion jmr40, but if all the powder is burned in 6-10 inches, then why do many rifles have fireballs coming out of the muzzle with slow powders? Hmm, maybe the words don't mean what you think they mean. :D
 
"The powder that produces the highest velocities in a longer barrel will be the powder that gets the highest velocities in a shorter barrel."

I believe this is the correct answer. The only drawback is muzzle blast and flash will most likely be greater. I shoot rifles in .308 Win. in three different barrel lengths, 18.5", 20" and 22". One rifle is a bit particular and will only shoot one load accurately. Powder that worked was W760 and the load produced 2550 FPS from the 18.5" barrel. I tried the same load in a 22" rifle and velocity was 2610 FPS. W760 as I recall is in the same burning range as the 4350's. Bullet was the 165 gr. Speer Hot Core. At one time my .308 was a 20" breed rifle and I push a 150 gr. Sierra Pr Hunter with a max load of H335. Muzzle blast was ear piercing and the flash so bright that at noon on a sunny August day in the desert the flash was brighter than the sun. Sure was one hell of a deer slaying load. Never used a 180 gr. bullet much in the .308 though.
Paul B.
 
The powder that produces the highest velocities in a longer barrel will be the powder that gets the highest velocities in a shorter barrel.
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In most cases this will be true, whether rifle or pistol.
 
2 Mausers (3006), one with a 24 inch barrel, one with a 16 inch
barrel ( Colombian short carbine )( both military rifles with a 1/10 twist)

The 16inch barrel produces a giant fire ball and much louder sound
( like a cannon )( gets everybody's attention )
I tried faster powders, that helped a little bit, using a magnum primer
also helped ( specially with ball powders )

But the velocity was still much lower than the longer barreled
rifles
Did not help enough to bother with, its still very loud with a huge
fire ball from the muzzle
 
I tried faster powders, that helped a little bit, using a magnum primer
also helped ( specially with ball powders )
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firewrench044, since TimSe, jmr40, Paul. B., steve4102 and now buck460XVR don't agree with you...I guess it did not happen.

Anyway, yes that is consistent with lab test results. The magnum primers push the peak pressure a little sooner, but not a huge benefit.
 
Well now that nobody agrees with anybody and 3006loader is
completely confused
He will probably try his experiment and see what happens

I tried and was disapointed
 
Originally posted by MarkCO:

firewrench044, since TimSe, jmr40, Paul. B., steve4102 and now buck460XVR don't agree with you...I guess it did not happen.
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I never said I didn't agree with Firewrench, you did. I agree that his use of faster powders probably did reduce the fireball and muzzleblast. This is why most folks use a faster powder is short barreled rifles. That and to reduce recoil...but all that comes with a cost...lower velocity. As I understand, the majority of powder is burned and peak pressure occurs in rifles, somewhere between 1 and 3 inches down the barrel. While there may be some remnant powder that burns farther down the barrel, what it adds to pressure and velocity is so insignificant it is generally moot. Similar to the use of Magnum primers with fast powders that do not need them. This is not a new theory, it has been discussed here and on every other gun forum on the internet a multitude of times and the general consensus is always the same. I have been told by powder manufacturers the same thing. Slower powders that produce the fastest velocities in long barrels also produce the fastest velocities in short barrels. Now the use of a faster powder to reduce recoil, muzzle jump and muzzle flash in a short barreled rifle, may make the shooter more accurate, thus the loss of a few FPS is negligible.

I also concur with Firewrench's statement.......

Did not help enough to bother with
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The muzzle flash is not caused by burning grains of powder coming out of the bore.
It is caused the the cases produced by the "burnt" powder igniting when they enter an oxygen rich envioronment. Slower powders can and usually do, produce more gas, more gas = more flash.
 
I am done with this one. Way too much ignorance regarding combustion processes on here. No matter what you think you know, can't beat Pv=nRT.

"burnt" powder igniting when they enter an oxygen rich envioronment
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Completely absurd.
 
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