ArmaLite National Match M-15: What Went Wrong?

As I said in my write-up of the Bridgeville High Power match, the ArmaLite National Match M-15 I was using malfunctioned. A lot. And the malfunctions looked EXACTLY like the one you see above. This picture, however, was taken on the 21st, well after the match ended. Even after throughly cleaning the rifle, it’s still having issues. We took it to the range aboard MCB Quantico to try and figure out what was going on, and I think I have it about figured . . .

We decided to start videotaping the malfunctions about 80 rounds into the day. By the time the first shots on this tape were fired, the gun was in a less than pristine state of cleanliness. The dirtier the bolt got, the worse it malfunctioned. It got to a point where I couldn’t even cycle the bolt using the charging handle anymore.

Why was this happening? We passed the rifle around, and the consensus was that the bolt was meeting resistance (more than the normal buffer spring) in the buffer tube. This slowed it down and caused it to fail to reliably cycle.

This issue was caused by a combination of a more abrasive than normal bolt carrier and possibly a malformation or other issue in the buffer tube itself. These issues slowed down the cycling of the bolt and in some cases even held the bolt to the rear for a split second before sending it home, which reduced the bolt’s energy and caused the failure to feed issues.

We confirmed part of our hypothesis by replacing the lower with a spare we had laying around, namely Ben’s exceedingly filthy 9mm lower. We removed the 9mm magazine plug and retested the gun with the same ammunition, and this time the gun cycled without an issue. The bolt did fail to lock to the rear after each magazine, but I’m more willing to chalk that up to Ben’s filthy (did I mention that already? Because it really was) lower.

So what’s the fix? As far as we can figure, a new stock, buffer tube and chromed bolt carrier should do the trick. It’s really a shame too; with the exception of this mechanical issue the ArmaLite National Match M-15 is an excellent rifle. Great trigger. Excellent accuracy. Terrific ergonomics. Hopefully, I can get it running in time for the Remembering the Brave match next weekend.

BEFORE YOU EVEN SAY IT, I do in fact know how to properly maintain an AR-15. I’ve used one in competition for years without any malfunctions (except those caused by some light loads I cooked up by accident). If I can maintain a high-end competition AR-15 and a service rifle AR-15 for a few years the probability of me cocking-up an identical rifle within a few months is practically nonexistent.

comments

  1. avatar Severe says:

    Because it cycled reliably with the other lower, here’s my first guess… I don’t see mention of the type of ammo you’re using; namely .223 vs 5.56. With the rifle length gas system if you’re using under powered ammo with a rifle buffer you could get short stroking. Which appears to be what you’re having. The bolt doesn’t have enough velocity to completely cycle.

    The ammo seems suspect because you say that after 80 rounds the rifle was having issues cycling. Keep that bolt wet! Really wet. 80 rounds of should not be enough to even phase a rifle.

    If you have access to that same 9mm lower, try just pulling the buffer and throwing it in your A2 lower. If it functions correctly then, you can start to fine tune what buffer you need. If not, then you can continue the investigation.

    I’ve been told to keep a buffer assembly on hand of just about every flavor; . That way when the ammo under performs you can ‘turn’ the rifle a bit. Especially when most of us shoot eastern block ammo these days to save money.

  2. Just a thought, been a while since I installed mine, but I believe there is a hole down the center of the screw that holds the buttstock in place so that air can escape as piston in the tube compresses the spring…could it be that hole is missing or got clogged up? I would imagine that would hinder (slightly) the buffer from freely compressing and expanding, if air cannot freely move in and out of the tube? Or the hole in the back of the buffer itself?

  3. avatar Jason says:

    New stock, buffer tube, and chromed bolt carrier? Why?

    Unless you’re made of money, try to isolate the issue. The stock shouldn’t have any impact on what goes on inside the buffer tube. It would be fairly strange for the buffer tube itself to be causing an issue. More than likely, it’s the buffer. In any case, replacing one part is cheaper than three. Swap out parts one at a time until you find the one that’s causing the issue. Not only will you save money, but you’ll learn more about your rifle.

    Go through the process a couple of times, and the next time you see someone else at the range having problems with their AR-15, you’ll get to be the grizzled old guy who pops it right open and says, “Well there’s your problem right there…”

    1. avatar Nick Leghorn says:

      Why change out all the parts? Because I have some spares of each lying around and I need this thing to work flawlessly this weekend. I’ll be taking the time to isolate exactly what the issue is once the Remembering the Brave match is over, but right now I just need the thing to work.

      If I didn’t have the parts on hand, you’re exactly right. I’d start with the cheapest part to replace and work my way up from there, seeing which part was the issue.

  4. avatar TTACer says:

    It is an extremely accurate but overly finicky system. Why it has lasted more or less unaltered for 50 years is beyond me.

  5. avatar Chris Dumm says:

    Nick,

    Your ‘slow-feed/no-feed’ malfunction looks like the same malfunction I encountered with the ArmaLite M15 we tested earlier this year.

    1. avatar Nick Leghorn says:

      Well damn.

      Did you find a solution?

  6. avatar Steven says:

    Had a similar issue in my DCM Armalite. The solution was a new Wolf recoil spring. Use the extra power for everything except light loads. ~$12.99 at MidwayUSA.

    In my experience, the Armalite DCM/NM chamber is a very tight with .223 only throat. Mine works best when the chamber is shinny clean and likes carefully sized and trimmed Remington .223 nickel plated brass.

  7. avatar james says:

    The Match M-15 is an excellent rifle, when it works. Now, there is a selling point.

  8. avatar Adam says:

    I remember when I had a problem like this with my armalite. I, very new the AR-15 at that time, had not properly aligned the gas block when replacing my hand guard and boom instant problems cycling.

  9. avatar Leo Atrox says:

    I recall reading a comparison on this very site between the Armalite and the Rock River Arms NM rifles. The author found that the Armalite was slightly more accurate for him, and he liked some of the other distinguishing features a bit more on the Armalite as well. It is with some amusement, then, that I am reading this post with that little voice in the back of my mind screaming: “The more accurate rifle is the one that fires.” The tighter the tolerances, the more finicky a rifle will be. Switching out parts might affect accuracy and zero a bit. Probably not noticeably, but some more “senstive” shooters would claim to notice the difference.

    1. avatar Nick Leghorn says:

      Yep, that was me and here is the review in question. I’ve updated the final ratings based on what has been going on, but I’m waiting to figure out exactly what the issue is before re-writing the review.

  10. avatar John says:

    OK, now I am scared to buy one… and I was looking at them HARD.

    Stupid question perhaps, but why accept this lemon from Armalite. They should fix or replace this IMMEDIATELY to your satisfaction. Did you not try to return it? I thought they had a lifetime warranty?

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