TaylorWSO @ ar15.com dropped a loaded Magpul polymer PMAGS onto concrete in -30 degrees, feed lip first:

So to the drop test. I wanted to see what they could do in the cold. I dropped it from the same table (3′ high) I have dropped metal mags from on the range. If you drop a metal mag on concrete from the same height it will damage the feed lips as to be unuseable-but you can bend them back. I was planning on dropping them on all sides but it broke before I could try it. From the table, fully loaded, no cover, both feed lips shattered when they hit the concrete. I expected it to break/crack but these things shot off and rounds went everywhere. I stopped the test right there as didn’t want to try it with any others on the other sides. You can see in the AK HTF that if empty they do fine in the cold.

So what does this mean.

IF you drop ANY mag loaded on the feed lips it will be useless. The Pmags might survive during the summer but all metal mags will bent hot/or cold. The metal mags can be bent back.

The plastic shatters when cold (duh) it doesn’t just crack.

I finally got a answer as to what these can do.

This test was dropping on concrete in cold weather. I had to clean off a spot to get down to the concrete. If the mags are dropped in the snow vs just concrete they do just fine. So the possibility of hitting on the feed lips in cold weather on a hard surface-very unlikely

The covers are great to keep out the snow – huge plus.

Overall they do just fine. I was surprised at the complete breaking vs. cracking buts that’s what cold can do.

The result: cracked/split feed lips:

uafgrad tried a simular experiment in even colder weather:

Ok Back to tougher in Alaska
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Here is where it set for a period of about 18 hours. This was the “hi” temp for the period
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The mag was fully loaded and dropped from a height of 36″ directly onto the feedlips (as previously requested) striking bare concrete.

Once it hit the ground, all but 6 of the rounds exited the magazine on to the ground.

Some plastics becomes become brittle in cold conditions, so this is not surprising. The good news is that Magpul are not sitting on their laurels. Their latest version of the PMAG can survive a drop from 5 feet onto concrete feed lip first, fully loaded in -30 F. See this video shot with a high speed camera:

A big thanks to Jay for the link.