Brownells AR-15 magazine reliability

[That Guy]

My girlfriends rifle (Colt 6920) ran into some issues today. We're talking about a barely used rifle that has worked flawlessly until now, but on the last (ie. second - now this is some high speed low drag training! :p ) magazine of the day the gun suddenly had multiple failures to feed (bolt over base). This was with a brand new, never before used Brownells aluminium magazine. Ammunition was the same Lithuanian 55gr FMJ (made by GGG) that has worked well in both our guns before. Since the gun has been running fine until now, I'm thinking this must be the magazines fault.

I've understood that this sort of thing ought to be fairly rare with "B-mags". But how rare of an occurrence are we talking about here? So far I've got ten of the bloody things stashed away (in addition to my training magazines, that is), and I'm hoping to buy many, many more while I still can - firing thirty rounds through each and every magazine in order to test fire them would be way too expensive to be economically feasible. How likely will I end up stashing junk magazines with my plan?

[StraitR]

Bolt over base malfunctions are caused by the inability of the magazine (specifically the spring) to keep up with the cyclic rate of the bolt. That doesn't necessarily mean it's always the magazines fault though. Oversized gas ports, worn out buffer springs, worn out magazine springs, too light of buffer, out of spec mag, out of spec lower, ammo power factor, or any combination of the above can contribute.

When you say, "the gun has been running fine until now", how are you qualifying that statement?

[That Guy]

When you say, "the gun has been running fine until now", how are you qualifying that statement?

The gun had been fired, by my count, some 450 times with zero malfunctions. Once this one particular magazine was inserted, many malfunctions. Either something in the gun just flat out broke right there, or it's the magazines fault. I'd say the odds are that the magazine is faulty.

(Obviously I can hopefully get her to the range as soon as possible with her rifle and some known good magazines to verify my theory, but at this point it seems the most plausible.)

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[StraitR]

You're free to diagnose as you see fit, I simply gave you the various factors and causes of your malfunction.

[That Guy]

And I explained the reasons why I came to the conclusion the magazine is probably at fault. Do you see some fault with my logic? If the issue were with something like an oversized gas port or another faulty or worn out part, I don't see how the malfunctions could have started so suddenly. (And a gun with under 500 rounds through it should not have worn out parts, I would think?) Different ammo might have explained it, but it was the exact same ammo as before, and in fact ammunition loaded from the exact same box to another magazine worked fine just minutes before. So in this particular instance, I feel the magazine is the likely culprit. But if you think I am wrong in this, I am always more than happy to learn why.

[JSGlock34]

Do you number your magazines?

[StraitR]

And I explained the reasons why I came to the conclusion the magazine is probably at fault. Do you see some fault with my logic? If the issue were with something like an oversized gas port or another faulty or worn out part, I don't see how the malfunctions could have started so suddenly. (And a gun with under 500 rounds through it should not have worn out parts, I would think?) Different ammo might have explained it, but it was the exact same ammo as before, and in fact ammunition loaded from the exact same box to another magazine worked fine just minutes before. So in this particular instance, I feel the magazine is the likely culprit. But if you think I am wrong in this, I am always more than happy to learn why.

It's hard to say. The magazine is most likely the culprit, but then again, magazines are more often than not the biggest contributor to malfunctions anyway. It's difficult to use MRBS (aka. trigger pulls vs malfunctions) to determine gun reliability without a significant number of rounds through the gun. 450 is better than a couple boxes, but it's not significant. Guns can run on the ragged edge of functionality right out of the box, but it often goes unnoticed until some kind of operating variance (mags, ammo, lube, dirt) flushes out the issue which was hiding skin deep from the start.

I'm not saying this is the case with your Colt, what I'm saying is I'm not familiar with your level of knowledge when it comes to AR's and diagnosing gun malfunctions online is a "try this, ok, now try this" thing at best anyway.

That said, I would suggest disassembling the problematic mag, inspect it for burrs or abnormalities, wipe it down and put it back together. Take it back to the range with some other known good mags and see what happens. I would load the magazines to capacity, being that full spring compression and max weight of the rounds often make a difference in magazine functionality. I would also take a few more new Brownell's mags and see if you can recreate the issue with those.

As JSGlock34 alluded to, numbering your mags to track issues like these.

[JSGlock34]

Every manufacturer can produce a lemon, but if we're talking about a factory complete 6920, I agree the more likely suspect is the aftermarket magazine, even if Brownells is considered a quality product. I think StraitR has provided good advice on inspecting the magazine for defects. If you've got a bad one, stomp on it with your boot and toss it in the trash.

If you've lost confidence in the Brownells magazines, there are other quality options (I recommend Magpul PMAGs, or Okay/Colt magazines if you must have aluminum). I'm not familiar with the Lithuanian ammunition you're using, but if problems persist I'd consider some Lake City (M193 or M855) 5.56mm ammunition for comparison.

[Malamute]

A while back someone mentioned a bad batch of Brownells mags (from several years ago). The feed lips had a noticeably different curve than normal. It was obvious looking at the mag with a round in it compared to a good one, only the tips of the lips touched the round instead of the curve of the lips matching the curve of the case. There were pics, but i dont recall exactly where or when i saw it, maybe here, maybe m4c.net.

[That Guy]

An update of sorts: while I still haven't been able to drag my girlfriend back to the range for rifle shooting, I did some dryfire with the magazine in question. Same thing, lots of bolt over base. Quite clearly a faulty magazine, which has by now been discarded.

Still a little unsure as to how rare an occurrence a faulty Brownells magazine is exactly. Apparently they should be good magazines. Just a little jarring to see a brand new magazine act this way, coming from the AK side. Hopefully I won't run into any more of those.

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[That Guy]

Another range trip, another bolt over base malfunction. With a different gun this time.

I gave my girlfriend Brownells magazines which we've used before and know to be good, and her gun ran without issues. However I tested one of our unused Brownells magazines in my gun and had the first malfunction ever in my rifle. (My rifle is a similar Colt 6920 as my girlfriends, and has about the same amount of live rounds through it. I've done somewhat more dry fire with mine, but that shouldn't make a difference here. My rifle is recently cleaned, well lubricated, and hasn't been used enough for springs to have worn out.) Now granted, with this magazine I only got one failure to feed out of the whole magazine, but that's still not acceptable.

Not getting a farm fuzzy feeling about these magazines anymore... First one magazine malfunctioned in live fire in my girlfriends gun and in dry fire in my gun, and now a second magazine which malfunctioned in my gun during live fire. And that's out of five magazines so far. Now granted, those Brownells magazines which do work, work very well - I think our Brownells magazine numbered #1 is the most used magazine in the house, and it has never given either of us any trouble. And the ones that create malfunction, do so right away, so it's easy to check which ones work. Still though, the failure rate is a tad excessive for me.

Ammunition remains the same GGG 55gr FMJ as before.

I'm thinking the next batch of magazine I buy will be gen 2 P-Mags. The ones we have have never given us any trouble. And the price will be very close to the aluminium Brownells magazines.

[Glenn E. Meyer]

Anecdotally, yesterday we had a carbine match. In one stage, we loaded a full mag and then gave the SO an empty mag so he could load it with 1 to 5 rounds.

The stage was:

1. Engage four targets with two rounds each.
2. Then do a tac or speed reload.
3. You reload with the mag with unknown number of rounds.
4. When it goes dry, you continue to engage by transitioning to your handgun. By then the targets are the farthest.

So when I reload the mystery mag - which is a Brownell's 20 rounder, it give me a nasty double feed which does not immediately clear with standard yelling and screaming. I continue with my handgun. Only 4 down for the stage but time went to hell.

I vaguely recall some discussion of the twenty rounders being funky at times. The other mags in the match were Brownell 30s and Pmag 30s - not a hitch with them.

Ammo was a mixture of misc. 55 gr. PMC, WWB and the like.

Thoughts?