1) Barrel length has no direct influence on accuracy. With a particular load, yes, you could shorten the barrel to match the muzzle exit time of the load.... or you could work up a better load to match the existing barrel... which seems easier.
2)Barrel length has no direct influence on bullet stability. Longer barrels produce more velocity for a given load but what matters is the velocity and the twist rate. You might not be able to get the velocity to stabilize the bullet from a shorter barrel but it's not directly the barrel's length that matters. Also, the difference between an 18" and a 24" barrel could be as little as 150fps, possibly less. A bullet that's unstable at the 18" velocity is still not going to be much more stable 150fps faster.
3)Generally speaking, once a bullet is gyroscopically stabilized, it will remain so, for practical purposes. It will hit the ground or the target before it destabilizes. The resistance to it's forward movement is much greater than the resistance to it's spin. In other words, the spin doesn't slow down much and the spin is what makes it's stable, not the velocity.
Still happily answering to the call-sign Peetza.
You do not HAVE a soul. You ARE a soul. You HAVE a body.
He is no fool who gives what he can not keep to gain what he can not lose.
-Jim Eliott, paraphrasing Philip Henry.
Last edited by Brian Pfleuger; February 14, 2013 at 08:47 AM.