Without a shadow of a doubt a .416 Remington Magnum in a Remington 700. I've fired All sort's of 458's, 416's, .375's but that Remington was brutal. The stock was all wrong. Close second is my Remington 870 Super Mag with 3.5" Heavy Shot loads. I fire about 3 rounds per season. 2 to check the pattern and 1 to down a turkey. Knocks em down like they got hit by a truck.