Quote:
Originally Posted by Theohazard
But it does. A shorter barrel produces lower velocity. And to achieve the same level of stability, a slower bullet needs to be spun a little bit faster than the same bullet at a higher velocity.
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You are correct that indirectly the barrel length has an influence on bullet RPM by way of greater velocity from a longer barrel (to a point). The difference in velocity between same load in 16" and 20" bbl is at most 200fps compared to say 3,000 fps total or about 7%. Which in practical terms will have no noticeable effect on bullet stability in the normal range of of bullet wright lengths used for 1:7 twist rifles. Perhaps at the margin such as 45 gr bullet the 20" would be slightly better. But I doubt there is any common circumstance in which the 20" bbl is significantly WORSE as implied by the OP's brother.