Tuesday, September 16, 2014

Barrel Length and Powder Burn Rate

We've talked about it. Here's an example.

Click to biggify. H/T to Miguel at gunfreezone.net


Borepatch said...


Tony Tsquared said...

That kind of reminds me of when I had some extremely hot 44 Mag loads.

drjim said...

This might not be very "scientific", but I could swear the rounds I fire out of my Marlin 1894 (20" barrel) hit the steel with a bigger "BOING!" at 50 yards than the same ones fired out of my wife's TRR-8 (5" barrel) revolver.

R.K. Brumbelow said...

@Drjim It probably does, you can get a chronograph for between 90 and 320 if you want a more scientific result.

Ideally overpressure in the barrel should fall to 0 at the transition phase, practically it never does.

Generally a longer barrel will yield higher velocities of the bullet so long as pressure inside the barrel (behind the bullet) is higher than the pressure in front of the bullet. Any uncombusted powder is basically wasted once the bullet leaves the barrel.

That being said, my almost 70 yr old mother carries a derringer my grandfather bought for her when she was a teenager and we have always joked it was a lineup gun. As in the powder burns on the perp will make it easy to pick him out of a lineup. As the effective range of a .22LR out of a 2.5 inch barrel is about 3 ft which is about the same as the flash.