Red, the MV generated by the 300 winny is the culprit, nothing is as hard on bullets as a high velocity impact, and nothing is as hard on meat as a high velocity impact. if every animal you killed was beyond 300 yards the problem wouldn't exist, only solution is slow the bullet down, or make the bullet so heavy it can't drive it fast. its what happens when you use an elk/moose capable cartridge on deer, The prescription I would write for you is a new 7mm/08.
RR