Originally Posted by PHILatDCMFirearmsSC
only thing i dont like about 9mm is the velocity on the round.. would rather not have to worry about where my round goes after defending myself from a perp.
although i always know my target and backstop id rather have less to worry about
Yes, over penetration is a very real worry in just about any caliber if the right bullet and load is not selected. This is especially true of the 147 grain 9mm bullets I have personally tested. As far as velocity, a .40 will easily exceed 1200FPS with a 155 grain bullet, which is very capable of over penetration. The .40 is only a little over one millimeter larger in diameter than than a 9mm bullet with a similar mass and velocity.
I personally don't see any ballistic advantage of the .40 and I find the biting recoil much more unpleasant than either the 9mm or 45 ACP. I realize that others will have a different opinion, but as a long time handloader, competitive shooter, plinker and instructor that's just my opinion.