Let me see if I'm right. I have TONS of .40 mags and they can be used in .357, and in 9mm also long as I have a barrel conversion, but not in a 10mm?
.40S&W and .357Sig Glocks are essentially identical other than the caliber. These pistols can accept a 9mm conversion barrel, and the mags and barrels are also interchangeable with each other.
9mm Glocks have a similar-size frame to the .40S&W/.357Sig pistols but cannot be readily converted to fire those cartridges.
None of these pistols will accept 10mm because the round is too long to fit in the mag well and is too powerful.
Double-stack 10mm and .45ACP Glocks- the G20, G21, G29, and G30- have a larger and heavier-duty frame than the above-mentioned pistols. They can be converted to fire 9mm, .40S&W*, and .357Sig, along with a variety of other rounds.
Got it now?
*Footnote: Although some shooters have done it with some success, it is a matter of considerable debate whether it is safe and/or smart to fire .40S&W in a 10mm G20/G29 without a conversion barrel. This has been discussed in other threads, and I don't want to branch out into that topic here, but I feel it warrants a brief mention.