Rifle Mags Measured In “Footpounds”

Re-Post from MDT


M14 Mags. polymer Thermold 20 rounders on the left, steel Check Mate Industries 20 rounders on the right.

I hear all the time about guys trying to lighten their combat/Survival loads, and sometimes it leads to ridiculous measures. Although there are some things that can be done to reduce those “Footpounds”, sometimes, you have to just flog your “Inner Pussy” till it goes back in and do the deed. One of the things that has made a big difference in the weight of those loads is the availability of polymer mags that can replace the steel mil issue ones. There are a number of manufacturers out there, but only a few have a good rep for reliability and durability, and the two I have actually used that have been reliable are Thermold and Magpul (I’ve haven’t used US Palm, but I have heard nothing but good about them). The Tapco mags I’ve used were in an AKMS, and they were hit or miss on the reliability and durability scale.

Although the Magpul mags are available for the AR, and I use them like many others people out there. The difference between the GI aluminum mag weight, and the Magpul polymer weight isn’t much, and the point of this article is to show the big difference between steel and polymer mag weight. There are two weapons that I use that the regular mil issue (“mil issue” is an important distinction. Some steel mags like promag, or the Korean ones are lighter and less robust and reliable than mil issue mags) mags available for them are steel, the M14/M1A, and the AKMS. While you are not going to find a polymer mag that is more durable, and generally repairable, than steel, the trade off between steel and polymer is significant, and if possible, you should look at getting some of the polymers for those weapons systems if you are trying to increase your round count that is carried, or reduce your overall weight.


AKM mags, polymer Magpul 30 rounders on left and steel mil issue 30 rounders on the right.

The way I conducted the weigh-in was as follows. I assembled 8 steel twenty round mil issue M14 mags, 8 polymer Thermold twenty round M14 mags for the M1A weigh-in. For the AKMS, I collected 6 steel mil issue AK mags, and 6 Magpul polymer AK mags. Why 8 M14 mags but only 6 AK mags? The mags were measure in bulk (by there “Basic load” total weight) to get an overall weight of the group of mags being weighed. I consider 8 twenty round mags ( 160 rounds) for the M14 to be my minimum basic load that is carried, and for an AK I consider 6 thirty round mags ( 180 rounds) as the minimum basic load I would carry (not counting the mag in either weapon). I consider 180 rounds as the minimum I would carry for a battle rifle, and 210 rounds as the minimum I’d carry in an assault rifle.

The totals are as follows:

Steel mags:

  • M14/M1A: 8 steel CMI (check Mate industries) twenty round mags weigh 12 pounds
  • AK: 6 steel thirty round mags weigh 10 pounds

Polymer mags

  • M14/M1A: 8 polymer Thermold 20 round mags weigh 9 pounds
  • AK: 6 polymer Magpul thirty round mags weigh 8 pounds

So how does this round out in the “Footpounds” department? Well, for something like the M1A, it means if you go with polymer, you can carry two extra 20 round mags (since the steel mags weigh 1.5 pounds, and the total polymer weight of the basic load is 3 pounds lighter), or 80 extra loose 7.62 Nato rounds. For the AKM rifle, you can carry one extra 30 round mag (since the steel mag “Basic load” total was two pounds heavier, and the polymer mags weigh 1 1/3lbs.) or 80 extra loose 7.62x39S rounds.

If you do as some suggest, and carry 4-8 extra loaded mags in your ruck, your weight savings, or extra rounds/mags count really starts to go up. Just for the M1A alone, if you carry 16  mags, now, with polymer, you can carry 160 rounds of loose extra ammo or four extra loaded 20 round mags for the same given weight that you would have with 16 steel mags, and all you are doing is making a mag material construction change.

I have heard some talk about the Thermold mags being junk, so here’s MY experience (YMMV). I have been using Thermold M14/M1A mags ( I purchased 3 at that time) since 1993, and I have never had an issue with them. I recently purchased a number of them for the M1A, and the results have been similar. I have never used Thermolds in an AR, so I can’t speak to their reliability or durability, but honestly, when it comes to AR mags, why wouldn’t you go with Magpul? They are cheap and readily available, and have all kinds of glowing recommendations by their users, of which I am one. The Magpul AK mags I purchased for my AKMS have worked flawlessly, which is something, as I said earlier that I can’t say about the Tapco polymer mags. This obviously isn’t the “Be all, End all” of the issue, but I hope my $.02 has helped you out.



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