Round the edges of the ejector slightly. Use a stiffer recoil spring to reduce the velocity of the slide at the moment the case makes contact with it. Get an EGW square bottom firing pin stop.
They square bottom firing pin stop uses mechanical disadvantage early in hammer cocking to delay unlocking a little. That also reduces slide velocity, frame battering by the slide, and muzzle flip and perceived recoil. The square bottom was Brownings original design, but the military changed it because some soldiers complained about the effort needed to rack the slide. Putting this part back to Browning's design increases that difficulty in return for the benefits. If you cock the hammer before racking the slide, the difference isn't there.
