ORIGINAL: stubblejumper
If I remember correctly for every inch more in barrel length you gain 50fps in most rifles and I believe that most ammo companies use 24 and 26 inch barrels for there velocity tests.
Most tests are done with 24" or 26" barrels.Some low velocity rounds may only gain 10fps per inch,while some large capacity.high velocity cartridges may gain 40-50fps per inch.Then again a rifle with a tight chamber and a 24" barrel may produce more velocity than another rifle with a 26" barrel.Most test barrels have minimum spec barrels which normally produce more velocity than a standard factory barrel of the same length.
I agree... I think the old days of using 30" and longer test bbls is over...
DM