Sharpsdressed Man said:
Since handguns are marginal to poor bear defense, that 100 fps advantage might look pretty good in the field. One must also consider that the .40 operates at the top of its own pressure spectrum (it was designed that way), and the beefier 10mm pistols can be hot-rodded more if one sees fit to go into that area. The .40 is MORE PRACTICAL, as brass and ammo are more plentiful, and a person has to handload to take the 10mm to potential. That is the ONLY REAL advantage of the .40 over the 10mm. Once you decide to handload, the .40 is left behind, ballistically, in a significant way.
I can understand that somebody might want all they can get velocity wise, no matter how much or how little. However, concerning pressures between the .40 and 10mm, both are even technically almost the same. According to SAAMI specs there is only 2,500 PSI difference between the two, and that's a pretty small margin.
To be clear, you have to handload ANY cartridge, not just the 10mm, to get the most out of it. You can't go to Walmart and buy maxed out 10mm, nor can you go there and buy maxed out .40 S&W, or 9mm, or .45 ACP, etc. By maxed out, I'm not just talking about pressure, but I'm talking about velocity since you can max out in pressure with rather low velocity or with rather high velocity depending on powder used.
By you saying the 10mm can significantly leave the .40 S&W behind ballistically, what do you consider significant? Just wondering. The reason I say that is because I agree that the 10mm is faster, but I don't think I would call it significantly faster. I still maintain that with equal length barrels, same bullet, and same powder, the 10mm isn't "significant" step up. Check this out:
Just to use Longshot as an example, look at the numbers. The 10mm with "max" data (neither are loaded to true max) shows to be faster than the .40 S&W by almost 130 fps. See that the 10mm is coming from a longer 5" barrel, so if you were to shoot it from a 4" barrel, I'd guess the 10mm would lose at least 50 fps, maybe more. But look at the pressure, if you were to even out the pressure (by either dropping the 10mm or raising the .40), the difference between the two would decrease even further, and to me the resulting velocity is not significant. What's worse is that with both loads, I'm really getting around 1150 fps out of a 4" G23 but get around 1260 fps out of the 4.6" G20.