Thread: Projectile vs barrel length

Originally Posted by Dead is better

It does drop but it's still there, adding velocity right till the last mm.

Yes some pressure is available till exit which is why longer barrels give higher velocity but the amount of pressure available is determined early in the process. As the projectile travels down the barrel the internal volume available grows substantially and quickly becomes to great for any still burning powder to have any affect.

Originally Posted by Dead is better

Say you're right. Does this mean short barrel guys should start using magnum powders because they have flatter pressure curves?

It depends on the chamber and projectile. In simple terms for example if 2217 gives the best velocity for a particular 338 300gr combination in a 28 inch barrel it will give the best velocity in a 22 inch. There is no free lunch, you cant chop a barrel , throw in a faster powder and get velocity back without running higher peak pressure or dropping bullet weight. Be nice though eh, I could have a 15 in 7mm remag pushing162 amax with BM2