Load for 308 pistol

[Greg Curci]

I'm in the process of building a 308 pistol with 7.75 inch barrel. Looking for help on load development. I'll be using RL 15 or IMR 4064 to start. Reloading manuals I have only show for 22 or 24 inch barrel. If I use the same load data and work up will the pressure be too much for the smaller barrel? Thank you in advance.

[ar15barrels]

Peak pressure will be the same with any barrel length over about 5" as the peak pressure with those powders develops in the first couple inches of bullet travel.
After the peak pressure, the pressure is constantly dropping until the bullet leaves the muzzle.

223vs308.gif

[Fjold]

I was going to say that peak pressure is reached just after when the bullet hits the leade (where the lands start) so barrel length has no effect on peak pressure.

[Spyder]

I just shoot Wolf and Tula 308 out of my pistol. Ballistics are worse than 30-30 and it makes a fantastic noise and flash. It's more to irritate anyone within a mile or so with ten rounds of rapid fire and a ridiculous muzzle brake, than it is to effectively put rounds on target. Short barrel with slow burning russian powder and no flash suppressant makes for obnoxious.

[sofbak]

^^;
Well, there are good reasons for the crummy ballistics, the noise, and the flash. It has everything to do with a specific chemical combustion characteristic of the rifle powder used.

All cartridge propellants have a specific value for this characteristic. I'll let all you plebes figure out what that is, and why a rifle powder is no bueno for this short-barrel application.

Oh, and Merry Christmas.