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Bolt Carrier Group Failures

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Has anyone ever experienced a failure of any component in their BCG?  I read a lot of posts about AR problems in general, but unless I specifically search for BCG failures, they don't seem to crop up that often. When BCG problems do pop up, it's usually a firing pin that failed.   I've used budget BCGs and spendy BCGs (All my BCGs are HP and MPI inspected.) and to be honest, they are all reliable and I cant tell why one is worth $80 and another is worth $300. 

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I have seen many BCGs fail, however never from a bad firing pin. I did see a fairly experienced, and indignant, SOF Group Sgt have repeated fail to fire - a little investigation revealed that he did not put his BCG back together correctly after cleaning his rifle back in his hotel room the night before. Much finger pointing and laughing followed. 

Most BCG issues I have seen are bad staking allowing the gas key to come loose. 

I have also seen a lot of just plain out of spec parts - most commonly a bad cam pin, then bad bolt itself.

Also, bolt failure at a rediculously low round count - like sheared bolt lugs at under 2000 rounds. These were commonly on hobby level guns like Stag, Olympic, and Bushmaster.

The BCG is the heart of the system - Buy quality partsZ That doesn’t mean you need a $400 Uncle Cheech’s Unobtaonium Coated, low mass, high reliability BCG, but absolutely Mil-spec is a good place to start. Do your research and buy with confidence.

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I caught it before failure, but I did have a poorly machined carrier begin cutting the cam pin. I agree with HE, staked gas key (with good staking, sometimes the staking doesn't even touch the screws), proper steel, and phosphate is fine. That being said I have a chrome carrier because I hate having to scrub.

 

I missed this forum, haven't been online in a long time.

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I like standard Mil-Spec coatings on my BCG and a standard weight and shape.

Don’t get me wrong, easier to clean, self libricating, cooler running, faster reciprocating all sounds great. But, the rifle is still generating the same amount of heat and carbon. It has to go somewhere. The AR was designed to work a certain way. Changing the characteristics of the BCG means the heat and crud have to go somewhere it wasn’t designed to and I don’t know what that will do.

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I've seen 2, first one not sure what kind it was but it was a high dollar rifle so I'm sure it wasn't a cheap bcg, the gas key sheared both bolts off flush. Second one was a JP and the bolt snapped in half right at the hole for the cam pin. Supposedly that rifle had 10k rounds through it but I doubt it. 

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Recently had to return a bolt carrier from Fail Zero that I purchased from Primary Arms because the gas key was out of spec. A replacement worked fine. So much for Fail Zero( slogan: Failure is Not and Option) Found out from Jimmy at GFH that it is not the first one from Fail Zero that he has seen fail. It is the first bolt carrier that I have owned that failed. 

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Had a camp pin shear right below the head. It was a cam pin I had to source individually, and it looked weird form the start, like it had been phosphated, shot peened or media tumbled and phosphated again. It also worse shiny spots in it in a weird way before failing completely. Failed in less than 1000 rounds. Main problem with getting it fixed is that almost nobody says who they source their cam pins from. 

So I went to a purveyor of fancy high quality BCGs and bought their house brand cam pin because at least they were willing to put their name on it. Has worked out for a couple thousand rounds so far. 

 

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I must be the luckiest guy in the world!

With the amount of shooting I do I guess I have 20k rounds on various ARs and haven't had any BCG failures.

Now I do make sure that my bolts are Mag Particle inspected.  But they're mostly PSA BCGs.

I have replaced cam pins when I see wear. I do grease cam surfaces and sometimes the bearing surfaces on locking lugs. Never a problem with gas keys.

I do shoot weird calibers in my ARs (hot stuff) 22 Nosler and 6mmAR hand load and push the envelope.

Maybe I maintain better?  Maybe just lucky.

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On 1/15/2018 at 2:37 PM, High Exposure said:

Also, bolt failure at a rediculously low round count - like sheared bolt lugs at under 2000 rounds. These were commonly on hobby level guns like Stag, Olympic, and Bushmaster.

The BCG is the heart of the system - Buy quality partsZ That doesn’t mean you need a $400 Uncle Cheech’s Unobtaonium Coated, low mass, high reliability BCG, but absolutely Mil-spec is a good place to start. Do your research and buy with confidence.

BCM, Spikes, Colt, and Daniel Defense are all priced reasonably and are the best for real world use. 

 

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17 minutes ago, Ray Ray said:

BCM, Spikes, Colt, and Daniel Defense are all priced reasonably and are the best for real world use. 

 

Pretty much agree Ray... But the only faulty rifle I have seen right out of the factory was a Stag.  Go figure.

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40 minutes ago, Old School said:

Pretty much agree Ray... But the only faulty rifle I have seen right out of the factory was a Stag.  Go figure.

Stag, Del-Ton and DPMS for me.  I owned the first two and they were just unreliable.  The DPMS was a friends, total junk.

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14 minutes ago, Ray Ray said:

Stag, Del-Ton and DPMS for me.  I owned the first two and they were just unreliable.  The DPMS was a friends, total junk.

See Ray this is where we part ways.  I've owned both factory Delton and DPMS and never had a problem with them.  Now I didn't run them as machine guns and mag dumps were rare if ever.  Reliable and certainly not jamomatics.  What kind of problems did you have?

Oh BTW the triggers were always worst than terrible.  Like fingers across a chalk board and like 8-10 lbs.

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15 minutes ago, Old School said:

See Ray this is where we part ways.  I've owned both factory Delton and DPMS and never had a problem with them.  Now I didn't run them as machine guns and mag dumps were rare if ever.  Reliable and certainly not jamomatics.  What kind of problems did you have?

Oh BTW the triggers were always worst than terrible.  Like fingers across a chalk board and like 8-10 lbs.

This was 12 or so years ago so maybe these companies have upped their game but the Del-Ton was just not reliable.  The Stag didn't like steel cased ammo and it died.  The Del-Ton was about the same, but it also didn't like some brass stuff.  I forgot what it was.  Its finish and parts where painted with spray paint.  The DPMS was crap.  Finish was almost as bad as Del-Ton.  

They are toys.  Or were. 

Now, it's 2018 and I believe SOME of these companies may have cleaned house and decided to build a decent product (think S&W) but they still aren't at BCM/Spikes/Daniel Defense/Colt levels.

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