Most commercially available 10mm rounds are well below the power that the 10mm was originally designed for. I believe this is leftover from when the FBI was using the stuff and decided to tame it down a bit.The Annoyed Man wrote:I sometimes carry a .40 cal, but had never fired a 10mm until one day, Crossfire's husband Marty, let me fire his 10mm and .40 cal Glocks back to back so I could see the difference. I have to say, I don't know how Marty's loads compared to other 10mm loads, but it didn't seem any worse to me than .45 ACP - my regular carry caliber - and it felt only a little bit stronger than the .40 cal. I wish I could tell you what the bullet weights were for certain, but I think they were in the 165 grain vicinity. Marty describes the 10mm as "a big pussycat."
I've been shooting .44 magnums (240 grains, 1200 fps) for years out of a revolver. Perhaps that's why the 10mm didn't seem all that stunning to me.
That's the origin of the .40S&W. Smith & Wesson looked at the downloaded 10mm and figured that at the lower velocities, they could do the same thing with a shorter case and chamber it in the same frames they used for 9mm. So that became the .40S&W. (It has sometimes been referred to as the forty short and weak or the forty slow and wimpy by people comparing it to the hot 10mm stuff.)
But full power 10mm, like the Double Tap ammo mentioned, is in the same ballpark as .41 Mag.