I did the barrel swap in my Shield 40, so the recoil/flip can be compared with the same gun. The 9mm has less felt recoil and flip than the 40. Does that make the 40 bad, no. I carry the Shield as a 40, and practice with both the 40 and 9mm. With high power SD ammo the 40 has noticeable more felt recoil and a little more flip than with high power SD 9mm ammo, But not so much as to make it uncomfortable or hard to control. I would estimate the 40 flip causes no more than 1/4 second extra time to get back on target, than the 9mm. The 40 is a more powerful caliber and for the minimal amount of extra felt recoil and flip, it is well worth it to me. Now for strictly targets, I would use 9mm and the cost per round is also less.