I have a Glock 19. As far as I know, it won't hurt it. It hasn't hut mine, anyway. I do it a lot, practicing mag changes. the pistol has yet to malfunction in any way.
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Glock 19
S&W 629 Classic
KelTec P32
"Oh yeah? Well I talk LOOOUDLY! And I carry a BIIIGGER stick! And I'll use it, too." -Yoesemite Sam