The Encore does not have gain twist rifling in the 460 S&W Mag. The reason S&W used gain twist rifling was because without it, torque was breaking scopes. It has nothing to do with velocity or with being easier on bullets On S&W revolvers in 460 S&W, the twist starts out at 1:100 and ends up at 1:20 at the muzzle. The twist in an Encore 460 S&W is 1:16. I broke 2 scopes with mine so I know it's hard on them.
Oh, and get a 460 S&W and not the 454 Casull. I've shot both and the 460 isn't that much worse and it performs better.