Magpul doesn't make mags for the .40cal glock , just 9mm ones .
The 9mm ones might work in the .40 , I know that .40 cal mags can be used in a 9mm , but it can be hit and miss for reliability.
You just blew my mind Greenhorse! I was gonna refute the .40 fitting in a 9mm mag so I thought I would try it first and you can actually load .40 into 9mm mags! I was using genuine Glock mags for both. Not sure how they would cycle and shoot though.
Lol , Cool , if you get a chance to try it out , let us know if it works , I am curious about it now .
Only down side would be reduced capacity, a 9mm mag blocked for 10 would only hold 9 rounds of .40



























