Mec-Gar metal Glock mags

[1KPerDay]

Notice that the sides are creased to hold 9mms at the right stagger angle to slide up into the center feed lips. You can't just dump rounds into any width magazine you like.

Exactly. Making a reliable mag is more complicated than you might think. A column of staggered rounds has to move against the mag body and each other AND funnel down to one stack in this case. You go too wide for the diameter of the cartridge, or make the funnel too steep, and it stops feeding reliably. Mec Gar had to match the external dimensions of the Glock mag AND the internal dimensions, but with a thinner material. They stamped ribs on either side and one along the front to keep the rounds in the proper place.

 

[zaitcev]

Frankly, I'm surprised they're not getting more than a single round from ditching the plastic outer layer of a Glock mag.

No surprise at all. The rounds in G17 magazine are already stacked fully. So making the magazine wider cannot add any more capacity. Instead, making it wider only kills reliability, because of the added friction. In order to maintain the reliability, MecGar magazine has deep grooves stamped in the sides, which make the internal dimensions same as in every other dial stack 9mm magazine.

The Shield Arms magazines increase capacity because the factory G43 magazines were not dual stack ones. They worked more like M&P Shield magazines internally.

 

[zaitcev]

You go too wide for the diameter of the cartridge, or make the funnel too steep, and it stops feeding reliably.

While this is very true, there's some leeway. Consider the STEN magazine for example. By driving the rounds up with an incredibly strong spring, they can be made to de-stack in a rather steep funnel. While STEN magazines are unreliable by modern standards, they are reliable enough to fight a world war.

 

[Jim Watson]

Right. The STEN, also MP40, Reising, and M3 that I can think of offhand, had center feed magazines.
I think the Thompson, M38A, and Sterling were better off with their alternating feed lips.

 

[dla]

I like to load 40sw long, 1.16" instead of 1.125-1.135" SAAMI. Mostly to keep the pressure down. Glock mags will work to about 1.145".
I wonder if the metal mags have the room to load long?

 

[Gun-Reck]

If there is a Glock that would really benefit from a metal, staggered mag?

The G36 .45 ACP.

The OEM 6-round plastic wrapped inline - should easily hold at least a couple more staggered.

 

[EMC45]

Make a G36 or G42 mag and I’m on it!