The Model 72A experienced some re-built parts, notably a solid lifter; the previous 1 was split. Model 72s had no pull-excess weight adjustment screw as is discovered around the 69As. Together with the Superior Wall version, developed for the greater highly effective cartridges, just the top from the breech block https://highimpactrounds.com/product/winchester-super-x-22-lr-round-nose-40-gr-1300-fps-100-rd-box/