User blog comment:LondonDauntlessCorvair963/Guns of LMBW: The Game/@comment-5111283-20141010123130/@comment-26929881-20141014231444

Yeah, if you're well trained, then shoot the M1-Garand multiple times with good accuracy.

So since I'm not very familiar with the 9mm, I looked it up, and a report on them both on recoil was:

.40 S&W, "sharp and snappy" and slower to get back on target for follow up shots.

9mm: Less recoil