Magazine Monopod: Malfunction Maker?

This article is  from Brian, owner of  The New Rifleman.com  where he talks about his development as a modern day rifleman and his journey to become well rounded and proficient, as well as how his tools change in his quest.  This article is about  testing magazines as a method for support during firing while using the AR15/M4 rifle.

Lots of conjecture out their about magazine monopodding. There is plenty of debate over whether it will cause magazine related stoppages. I found, with my two rifles, that the issue of stoppages could be related to not only the rifle, but the brand of magazines. What are the distinguishing features of a rifle that will have failures when mono-podding vs one that will function fine?
An Easy Way to Stabilize the Shot

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Monopodding the mag is a quick and easy way to stabilize the shot. Recently it has gained more and more popularity judging by discussions on ar15.com and m4carbine.net. The crux of the argument belies the old military “doctrine” of never-resting the rifle on the magazine. Various posters report thousands of rounds on a monopodded magazine and they will report the stability benefits of doing so. Others report failures to feed.

I examined my rifles to judge the suitability of monopodding the magazines and came to a few conclusions.

1) Monopodding success or failure depends on the magazine, magazine well, and also the magazine release of an individual weapon

2) One rifle may have many issues with monopodding the magazine while other rifles will have zero issues

Where do the issues lie?

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Magazines
The magazine itself is not the only culprit if your rifle jams while monopoding. Check your individual rifle and a few different magazine brands. Magazine monopod is a great technique to stabilize the rifle if it won’t affect your weapon’s reliability.

Testing Your Rifle, Testing Your Mags

I have two rifles. PSA and a Maine manufactured Bushmaster. The PSA is a flat top DD upper with a Rainier Arms mil-spec bolt and carrier. The Bushy has an surplus FN A2 upper with a Windham Weaponry bolt carrier and a Mil-Spec bolt.

I have three types of magazines. USGI with Magpul Follower, Magpul PMAG Gen 2, and Magpul PMAG gen 3.

When you mono-pod the mag you are applying upward pressure on the magazine and the magazine release. If the magazine and rifle both meet the wrong criteria the feed lips of the magazine will scrape against the bottom of the bolt when applying this upward pressure.

Place your favorite magazine brand into rifle. Press rifle down on to magazine with decent weight. Hold down magazine catch with thumb. Cycle charging handle.

Did you feel any resistance?

The USGI has the thinnest feedlips and did not affect function in the flat top or A2. The PMAG gen 2 with the thicker feedlips scraped the bolt carrier of my flat top, but not my A2. PMAG gen 3 was the worst offender. This was interesting since the Gen 3 has Mag-well stops molded into the mag. The Gen 3 scrapes the bottom of the bolt heavily on both my A2 and flat top rifle when applying monopod pressure.

I removed the follower and spring from the magazines and repeated the test. Same results. P-Mags can introduce some friction into the feeding system.
What About the Rifle?

Factors that are in play here, I suspect, are magazine well tolerance since magazines can wiggle fore and aft (which could elevate the rear of the mags feedlips into scraping the bolt carrier), and magazine button / magazine catch placement. The PSA has more wiggle in the magazine catch assembly then the Bushmaster. It is miniscule difference, but with all the other factors combined it may be contributing.  Will problems be immediately apparent with your setup? That too depends…
“It works fine”

So where does the extra friction lie in the reliability equation? I shot my fully loaded Gen 3 Pmags while monopoding. I pushed down heavily on to the rifle. I had no malfunctions. The velocity of the bolt carrier and a strong buffer spring were able to overcome the resistance of the feed-lips scraping the bottom of the bolt… but what if things get dirty? Perhaps you take a carbine class and the oil, dirt, and burnt powder start to increase the viscosity of your oil. The bolt carrier slows down a bit due to the grime, powder, and thicker oil.

Then you go prone and monopod the mag. You fire one shot and then possibly a Failure to feed. I didn’t put a 500-600 rounds down range at the last range session I went too, so I couldn’t test the Gen 3 Pmag further than that. For now I will stick with USGI magazines. Perhaps I will start investing in L plates as well. The NHMTG USGI mags have been 100 % in both my rifles so I will continue to buy these magazines along with Magpul followers. Some things to consider are that the mag catch area stamped out of the mag may fatigue over time and eventually the aluminum feed-lips may start scraping the bolt carrier. If that happens time to trash the magazine.

Time to start numbering magazines to keep track of trouble mags in the future.

I love PMAGs, but I won’t work them into my routine for shooting off the magazine monopod. I think I am asking for a malfunction. The stability advantage of shooting from monopod prone is great enough that I will use USGI mags for now.
Wrapping Up

Individual weapons and setups are wholly unique. Different magazines and unique rifles could deliver an equation that is unreliable under the right circumstances. It is important to test different components and find something that works well for you. My rifles like USGI magazines and the bonus is I can monopod off the magazine without introducing reliability issues. While I didn’t have  failures with the Magpul products during my limited testing, I feel the feed-lips scraping the bottom of the bolt carrier while monopoding will lead to reliability issues. I have learned my rifle can tolerate a magazine monopod with USGI mags. I will invest in some L plates to use this technique on hard and soft surfaces.

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 I want to add to the magazine as mono-pod debate. The Canadian rifle team has been using the magazine for support in the monopod method since the 90s. They have never had a problem with it and have some thought that using the magazine, causes a sort of “free floating” of the rest of the rifle ( AR15s/C7 rifles of course) resulting in great results.  Noted trainer Pat Rogers also supports the monopod/magazine method if its needed.  There is something to remember about this that many people will not want to mention for fear of offending.  Ar15 rifles made to be close to to milspec or that are actually milspec , that is, made to the colt TDP, will not have a problem when using this method with proper made to spec magazines in good condition with good ammo.  One of the deals with the early Pmags, is they were made to work in a proper Milspec magazine well, ( colt TDP, real Milspec in other words).

Many bought the first gen Pmags and used them in guns with lowers not made to spec or even close to it and that was when some people reported the mags not working or falling free when empty. Magpul then changed the specs of the mags to work with anything.  That was not a problem with that Pmags, just a simple fact some peoples guns were a little out of spec.    I have never had a rifle within proper spec not work when using the magazine as a monopod.   If you have a rifle not made by the MFGs known to copy Colt’s mislpec measurements for the mag well. or a Colt rifle, or a mag built to work in any rifle or whatever combo it may be, you will have to test each one to ensure it will not fail you.  I personally feel that a rifle that cannot function 100 percent because of some kind of pressure on the magazine, when its not the magazine or ammos fault, can not be trusted for serious use of defense and should not be used for serious purpose.   Shawn

2 thoughts on “Magazine Monopod: Malfunction Maker?”

  1. I have had, and continue to have, a variety of lower receivers. Being that everyone and their mother makes lowers these days it would be safe to assume that there are a variety of rifles out there like min that could encounter problems with new magazines.

    Being that my PSA mag release area is loose / wiggles more than my old 90s bushmaster leads me to believe that the problem is the lower. I have had many gunshow lowers in the past that were too tight for mags to drop free all the way to “should the mag wiggle that much”?

    It’s just something we don’t think about when impulse buying a lower receiver.

    Now I will.

  2. I wish I had all the lowers I had collected over the years to test this out. Some ranged from loose as a goose to mag wont drop free tight. There are so many shops pumping out lowers that it is hard to discern a in spec product from a out of spec one while your impulse buying at the local fun shop.

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