Examples Of AR-15 Bolt Failures
BY Herschel Smith
5 years, 11 months ago
There are two takeaways for me. First, make sure to inspect the lugs on the bolt when you clean it, especially on either side of the extractor.
Second, have a spare BCG.
Then there is the expression “clicky and no bangy.” That will probably roll around in my head for a while.
[…] Examples Of AR-15 Bolt Failures […]
Wonder who made them or what kind of round count or if they are casting flaws. Looking is all good but this seems to beaproblem
Lubricate or die……..
In my experience bolt components are the most common show stopping failure point for a quality rifle.
Frequent inspection and having a spare BCG is great advice.
I’m liking this. Doesn’t matter what the metal/coating may be that eases having to clean carbon from your bolt, it’ll still fail. Or maybe sacrifice failure for ease of cleaning. Interesting. Seems the weak points are on either side of the extractor (as you’ve eluded to). Not the expert, but assuming extraction is pretty violent part of the cycle and those weak points being in proximity of that action. Herschel, being the engineer that you are, can’t they re-enforce these locations without compromising the balance of the entire bolt? Not being the metallurgist, are there better materials that could address this? Or is it not worth the time and effort when compared to expense of a replacement bolt? The cracks at the cam pin location seems obvious due to the thinness of that location. I guess if something is going to fail let it be the bolt. I’ve purchased replacement carriers after the last drought, I don’t want to be in that position again. Now it seems to be worse finding parts. I suspect the materials are the source of the drought today. Nice video and thanks for sharing.
@frog,
One of the commenters to the video pointed out that these failures are primarily on very highly used military guns, M4s and M16s. These guns have probably had 50,000 rounds shot through them, and the barrels replaced three or four times, along with dozens of BCG replacements.
Clean, inspect, lube, have replacement BCGs.
Essentially an abuse I’m not likely to put it through. It makes sense.
Thanks
It’s so good you don’t even have to clean them, they said…
@bobdog,
Well, Tim Harmsen did put that BCM through about 6000 rounds before cleaning/lubing. Some of this may have to do with the guns being Colt.
@ambiguousfrog –
JP Rifles has done what you suggested: different materials and some amount of re-engineering for the bolt. They ain’t cheap, but they have a lot of people singing their praises. I’ve got them in every rifle. None have gone through their barrels yet, so none of them have 10K round counts. I do carry a spare bolt (not JP…) – and I like believing I won’t need to get it out in the middle of a class, an ftx, or something more pressing.
Poor choice of material. That Bolt should have been made from 17-4 H1150,
@Brad,
I would assume a better and more modern, less low-cost-bidder, BCG would do much better, like one from Daniel Defense, Rock River Arms, LaRue, etc.
My opinion FailZero make the best BCG’s on the market. They’re still made from Chrome Molly, but they don’t over harden them and their plating is awesome quality.
I would like to have seen the .gov bolt lugs that gave out a little better.
Did they have the chamfer to assist in the unlocking of the bolt like the two bolts that failed at the cam pin cut in front had?
Makes me think about my M1897 Krag. Action is butter-smooth but only 2! locking lugs. Not so sure about current .30-40 ammo in this gun.
Another reason to “just say no”.
@John,
And you are under the impression that the second law of thermodynamics doesn’t apply to your choice of firearms? Where did you learn this?
“Makes me think about my M1897 Krag.”
That bolts lugs are about .312 wide. Come on man. It’s all about surface area.And we both know that weapon has no place in a contemporary gun battle. Bottom line, done properly, Stoners design is hard.to beat.
@Herschel
In “71” I was told my (oft jammed) M16-A1 action “floated in a sea of lubricants”.
In the “new” era, I see our people in the deserts of the world running around in the sand
armed with the Colt M4 that had the worst failure rate of the several competitors in the
Army contract testing but won because of politics. Sand and lube don’t mix well with
machinery I still remember the Army truck outfit that became lost going into Iraq and
was rolled up with the young female specialist taken prisoner and later freed.
The after action report stated all of the weapons malfunctioned due to “improper lubrication”.
I have other reasons but I’ll let these stand as is.
@John,
Second hand info, myths and make-believe. My son NEVER had any problems with either his SAW or his M4 in Fallujah. And he never had any problems during the half a million rounds he shot during work-up to deployment. And in tens of thousands of rounds I’ve shot, I’ve never had any problems.
Oftentimes, what you’ll see is blame for personnel failures directed somewhere else.
@Herschel
“https://www.latimes.com/archives/la-xpm-2003-jul-10-fg-report10-story.html
Most of the soldiers in this group report that they experienced weapons malfunctions,” the Army says. “These malfunctions may have resulted from inadequate individual maintenance in a desert environment.”
“Defense Review” M4 failures in competetive testing:
https://www.defensereview.com/colt-m4-carbine-finishes-last-in-latest-us-army-small-arms-reliability-test/
@John,
Oh, I’m sure that’s what they ‘report’.
The M-4s I have been around were pretty darn reliable. Now I never shot a half million rounds through them. I have shot them enough to trust them when they have been properly taken care of. I am of the opinion that the 20″ length A2s and subsequent varieties were the best and most reliable of the type. Most will not agree with me on that.
I recall some reports of H&K 416s having problems as well as the XM8s. Those reports were from other allied countries and, if I remember correctly, they involved cold weather performance and some accuracy issues.
All of the reports I could find concerning the SCAR L were very positive. It may indeed be a better mousetrap. They are probably triple the cost of M4s and a determination would have to be made whether they are worth the cost. Interestingly the SCAR heavy has many detractors. Many in the military community say it has reliability issues.