Glock 21 mag in USP .45

[Postman]

Hi cap mags are almost impossible to find for the USP, I was wondering if anyone had had any luck modifying a Glock 21 mag. A chanel would have to be cut for the release to catch on and I'm not sure about the external demensions being the same, but my Glock 17 mags are close in size. Any oppinions or advice?

 

[Jedi Oomodo]

None, other than it's probably a bad idea. Glock mags are designed for Glocks, not USPs. I'll bet modifying a G21 mag would void its warranty, and if you used same in your USP, dollars-to-doughnuts you'd void your USP warranty, too.