barrel twist rates

Trying to decide which twist rate for 7 PRC rifle build. Going 22" barrel (either Proof or Carbon 6), would 7.5 twist be better than the 8 twist and would there be enough retained velocity at 1000 yds to ethically take elk at that distance with shorter barrel and slightly faster twist? -Brian

My question is pertaining to 6mm,but does the answer hold true for all calibers and using faster twist barrels than what has been the norm in previous years? Barrels twist rates have recently been getting faster due to the new high b.c. bullets such as the sierra 22cal. 95 grain that calls for a...