Kleanbore said:A 230 grain bullet fired at at 950 fps will generate more than one and one half times the felt recoil of a 124grain bullet grain bullet fired at 1126 fps from a firearm of the same mass.
Simple physics.
If I may humbly suggest that the GENERATED recoil is not the same as the FELT recoil.
In a semiautomatic, the generated recoil is partially absorbed by
1. A stronger recoil spring
2. A heavier slide
3. The slight movement of the frame
A full size steel frame .45ACP may have a less FELT recoil when compare to a subcompact polymer frame 9mm designed for CCW.
Another example, if I am recoil sensitive and yet I like the 45 caliber, I can replace the 230 grain with a 165 grain bullet and that will drop the recoil GENERATED almost down to the 9mm level that you quoted above. Thereby I can CCW a smaller compact .45ACP yet not experiencing much more FELT recoil than the 9mm.