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Firing Pin Woes with New Frontier Bolt


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Tried to shoot a match yesterday with my PCC, and had the firing pin break on the first stage. Sucks to be me. Knew something was majorly wrong so I just bagged the gun and RO'd the rest of the match. Pulled it apart tonight and found the pin in two pieces. Total round count less than 250. I'm going with bad heat treat, and will be calling New Frontier tomorrow, but does any one know if there is another mfg's proven firing pin that will work? Thanks in advance.

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Brownells sells a CMMG parts kit for the CMMG bolt and supposedly good with all Colt type AR 9mm bolts. I don't know if it's compatable with NFA bolts. It contains firing pin and extractor along with the spring for the firing pin, cotter pin to hold the firing pin, and roll pin for the extractor.  I think I could replace the firing pin in between stages at a match, but probably would need more time to replace/ tune the extractor (looks similar to a 1911 extractor).  Someday I plan on buying another complete CMMG bolt to keep as a spare.

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Have an ATI carbine, tip of FP broke off dry firing. I acttually heard it impacr wall in harage, but diidn'the realize what it was until I took it apart to lube before going to range and saw it looking odd.

Zero rounds through gun. ATI sent me another one free, and I bought a CMMG unit as a spare. 

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1 hour ago, robertg5322 said:

Have an ATI carbine, tip of FP broke off dry firing. I acttually heard it impacr wall in harage, but diidn'the realize what it was until I took it apart to lube before going to range and saw it looking odd.

Zero rounds through gun. ATI sent me another one free, and I bought a CMMG unit as a spare. 

I had the exact same thing happen with a NFA bolt. Zero rounds fired and only about a dozen or less dry fires and tip of firing pin broke off and hit the wall.

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28 minutes ago, robertg5322 said:

Interesting thing is there's a spring to stop or slow the pin from going forward and impacting the front of the firing pin tunnel which does not exist on a Mil-Spec AR FP. I've yet to break a .223 AR firing pin.

The firing pin works off inertia the spring keeps the pin to the rear much like a 1911 without the spring it won't stick out enough for the hammer to hit with enough force to work

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2 hours ago, carharttfarmer said:

The firing pin works off inertia the spring keeps the pin to the rear much like a 1911 without the spring it won't stick out enough for the hammer to hit with enough force to work

Seems the spring would also cushion the FP to some degree. No spring in a Mil-Spec Spec AR and they don't seem to be too hard on firing pins. 

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I welcome the firing pin return spring in my AR 9mm.  I hand load for my 9mm with the same very soft small pistol primers as I do with my reduced mainspring pistols.  Federals don't take much of a firing pin hit to set them off. I cringe every time I drop the bolt on a round during L&MR.  5.56 primers are harder and mil spec rifle primers are harder than Federal small pistol primers.  May be that's why 9mm Ars have the spring.

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11 hours ago, Odessa Straight said:

I welcome the firing pin return spring in my AR 9mm.  I hand load for my 9mm with the same very soft small pistol primers as I do with my reduced mainspring pistols.  Federals don't take much of a firing pin hit to set them off. I cringe every time I drop the bolt on a round during L&MR.  5.56 primers are harder and mil spec rifle primers are harder than Federal small pistol primers.  May be that's why 9mm Ars have the spring.

I didn't even think of the pistol primer softness issue, good point. Still odd how a spring cushioned pin breaks more than rarely and an uncushioned pin rarely breaks.

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Hello: I think they are breaking because they heat treated the tip to make it hard. What happened was that they did not draw it back so it stayed brittle. The shock wave going down the firing pin when not striking a primer caused the tip to break off because of the harmonics. Certain shotguns used to have the same problem. Thanks, Eric

Edited by Aircooled6racer
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2 hours ago, Aircooled6racer said:

Hello: I think they are breaking because they heat teated the tip to make it hard. What happened was that they did not draw it back so it stayed brittle. The shock wave going down the firing pin when not striking a primer caused the tip to break off because of the harmonics. Certain shotguns used to have the same problem. Thanks, Eric

Eric,

Mine broke before ever hitting a primer. I was dry firing in my garage, and not even a lot of dry firing. Maybe the shoulder hitting the front of the firing pin tunnel in the bolt caused the little nub to  go shooting across the garage, who knows. Seems that would be a bit more impact (steel on steel vs. steel on copper primer cup), which might explain it.

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So I got three rounds off on mine.  I've built several of these and this was my first problem. The firing pin was fine but the spring had moved up the collar on the firing pin which I guess slowed the inertia of the firing pin by rubbing on the firing pin channel.  So I replaced the spring and everything is working. 

Edited by Frank34
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  • 3 weeks later...

The black firing pins they they shipped some bolts with have a shoulder that the spring rides up on. The spring that comes with them is pretty weak and when it gets stuck up on the shoulder of the firing pin it stops hitting the primer. Not even a mark. Im not really sure if it's the firing pin or the spring. The colt firing pin is made from stainless steel and has no shoulder. 

When I emailed New Frontier Armory about the problem they sent me the colt style firing pin right away. They are really good to deal with. 

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