a maximum cartridge containing more powder (however fast-buning) may benefit (however little) from some amount of extra barrel length. Certainly, a 357 magnum coming out of a 16" barrel will do as well as one from a 7" barrel (it actually gains about 200 fps from the added 9 inches). I'm just hesitant to make the claim that nothing is lost by taking a 357 max barrel down to 16.5". Perhaps a 16.87" inch barrel
Okay, this got me thinking...
As I understand it, and this is in very basic terms for my very basic mind, at some point down the barrel the pressure of the gas that is pushing the bullet will decrease to a point that is less then the amount of drag (friction) that is trying to slow the bullet down. lessee here... is that right?
If there were no forces to slow the bullet down, once inertia was overcome the bullet would keep accelerating until the gas was no longer expanding.
Right, but we are not living in a vacuum so there is such a force...
And, if we accept that inertia is overcome at the peak of chamber pressure and from that point the gas pressure decreases for a number of reasons, even though powder is still being converted to gas until all the powder that can be consumed has been consumed...
Then, given that there is a force attempting to slow the projectile down during it's travel down the bore of the barrel, there must be some point along the length of the barrel when all the gas that can be created has been created and the volume of the space in which the gas is contained (the barrel) has increase to a point where the gas pressure is reduced to less then the amount necessary to overcome the force(s) that resist an increase in bullet's velocity and in fact these forces try to stop the bullet's movement, then that point is where the velocity of the bullet not only ceases to increase, but in fact starts to slow down!
So, the thing is to find out where that point on a given barrel is!
Okay, got through that with only a minor headache!
Am I on track so far?
I'm thinking another meaningless and statistically insignificant 'speriment here!
Gotta think about the assumptions though...