My only experience with this has been shooting roe deer with the same 65gr Sierra GK SBT bullets in two 22-250s, one 1:14" and one 1:8", and a 1:9.8 5,6x57 RWS.
Definetely, the bullets shot in the 1:8" 22-250 and the 1:9,8 5,6x57 expanded more violently, and penetrated less with more "splashing effect".
I believe John Barsness experienced the same effect on prairie dogs shooting 22-250s with different twists.
