One more thing on the .40 vs 10mm in Glocks, for a brief while I owned the G-20 and the G-35 at the same time.
Shooting side by side the recoil was less with the G-20 shooting CCI Blazers in both guns. Granted the CCI 10mm load is only slightly hotter than their .40 version, but the 20 was clearly a softer shooter.
Yes for the amount of power it delivers it is a soft shooter. When someone asks what it is like though I think of Norma level powers only because that is what it does that the .40S&W can not.
But even when delivering .40S&W power levels it is softer because the larger cartridge capacity allows you to reach the same pressures with less of an immediate spike. So you can deliver the same energy with less instant recoil.
.45 and .40 can do anything the 10mm can do
Ha ha. The .45 penetrates horrible due to its wide diameter and low energy on large animals or through cover. Once you put a .45ACP through cover most of its energy is used up, especialy with expanding ammunition.
The .40 S&W is a fine round, and the same as the 10mm Auto's low level loadings. It does not however have the versatility in power of the 10mm Auto.
You could defend yourself against a large bear with the 10mm if you had to. While round for round many more powerful revolvers seem better, you can deliver a lot more 10mm Auto rounds and they penetrate deep with the right loading.
You can also hunt things like deer very easily with a 10mm Auto. How many people down deer with one shot from a .40S&W?
The 10mm Auto is very similar to a .357 Magnum. The Glock 20 is like 16 rounds of .357 Magnum.
If you really want a .357 bullet you can also use 9x25Dillon from a 10mm auto gun, and send rounds screaming at around 2,000 FPS, with the same round capacity and generating around 900 foot pounds per round from a short barrel pistol. The 9x25Dillon is just a necked down 10mm Auto. All you need to do is buy a barrel.
You can't do that from a .40 S&W gun.
You can also get a .40S&W barrel for your 10mm Auto, but you can't get a 10mm Auto barrel for your .40S&W.