Instead of a single mag design for all pistols, a 2 way approach seems to be more sensible.
Glock pattern when possible, would be hard to fit in a metal frame, but easily doable in polymer guns, obviously glock does it, and the various aftermarket frames have been able to show that the glock mag doesn't mean you have to have glock like ergos
Beretta pattern for guns that can't quite fit the larger glock mags. I want to say the beretta mags are based on BHP mags? In any case it seems like most metal double stack mags are based on this pattern
These two patterns are probably the best representatives both price, options, and quality wise. I think its fair to say that the options for aftermarket glock and beretta mags are better (and more numerous) than the aftermarket options for HK, S&W, etc.
Its also much easier for primarily polymer companies like magpul or ETS to make glock mags that are at least somewhat functional.
And as far as quality of hk vs glock mags? I imagine the amount of glock mags that are out there dwarfs the amount of HK mags, so I wouldn't be so quick to judge based on a few reports
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