Glock 40/9mm mags interchangeable?

General Firearms Handguns - Semi Auto
1

I have heard you can use Glock 40 and 9mm mags in the opposite gun. Is this true?

2

Sure is.

Just dont put 9mm mags into a gun with a .40 chamber unless you’re absolutely sure you’ve got the 9mm conversion barrel in there…

3

I did that to my buddies 23 before…of course it fired but the casing didn’t eject and it looked huge lol

4

I ran my G19 with a 10 round G23 mag and had 1 to 2 malfunctions per mag.