Re: Thoughts on a 40mm
The history goes something like this:
The FBI was involved in a shootout with two heavily armed guys in Florida (??), and lost badly even though the two shooters were eventually killed. Their firearms of choice (38Special??) were highly inadequate and it cost them a couple of their agents lives. They requested a more effective round and started with the 10mm. The 10 was designed by the father of tactical shooting, but in full form is a 1911 sized gun with a very heavy recoil (It twists in the hand too). So the FBI requested downloaded ammo for their new 10's. That solved the recoil problem but then the small statured men and women found the gun too heavy and big for their small hands. The next step was to make a 10mm Short (called the S&W 40 and at the same level as the down loaded 10mm ammo) and fit it to a 9mm framed gun. So today you have the S&W 40 ammo and gun. It recoils about the same as a 45ACP in a gun as heavy as a 1911. But the mistake many make is buying a 25 or less ounce gun instead of a 40 ounce gun. That makes the recoil excessive.
I have a 10mm Colt Delta Elite. I shoot my reloads loaded down to 40S&W specs. I also have a CZ75B in 40S&W loaded to normal specs. Both guns are about the same weight and recoil about the same with these loads. I have owned and shot a High Power, a SIG P225, and a Taurus PT99 (Beretta 92 clone), all in 9mm. I also have a couple of 45ACP full sized and weight guns that I shoot regularly. I much prefer the big push of the 45ACP, the 10mm, and the 40S&W to the sharp recoil of the 9mm. I don't carry any of these guns and all mine are not lightweight guns. The new plastic light guns would be a handful in any of these calibers.
So if you are recoil sensitive you can buy the 40S&W gun. Just don't buy a lightweight model. 45ACP, 10mm, and 40S&W guns should be full sized and weight if you are that recoil sensitive person. I do not see the 9mm as an option for that person either as its recoil is sharp and for me no fun to shoot. To me a big steady push is better than a sharp lighter fast push (9mm). But we all get to choose.