Anyone bent an AR firing pin?

[Silverbullet2]

Guy's,
I just broke down my custom SPR Ar-15 to clean it up real good. It has a Billet Lower, Veltor VIS upper, and a Lothar 18" barrel. It has a chrome bolt carrier, and a Chip McCormick trigger. I do shoot it suppressed when I'm with some of my PD buddies. I shoot handloaded 69 grain Sierras with a near max charge of Win 748. I can't recall the weight cause I'm at the keyboard, and not my loading room. Always cycles, and never a hick-up. This is a pro build, not a homesmith.
Question, while having the bolt carrier broke down, I noticed the firing pin was bent a little bit. I rolled the FP on my bench, and sure enough, it was tweeked.
Anyone have any guesses to how this happened? Never heard of a pin get tweeked before.
Thanks, JPG

 

[Redmanss]

Re: Anyone bent an AR firing pin?

What type of BCG are you using? Is it a full auto type or does it have the cutout on the belly around the firing pin cup?

If it has the cutout, then the firing pin itself is what is riding against the hammer cocking it back, and that could be the cause of the bend. A change out of the bolt carrier and a new firing pin would fix the problem.

If your BCG is a chrome full auto type, then I'm clueless on what could be the cause of the bend.

Hope this helps.

 

[ArcticLight]

Re: Anyone bent an AR firing pin?

I've seen it on hot loads before, 69gr SMK's overloaded with 25.5 gr of Varget to shoot at 1k.

But you also see the other normal pressure signs too.

Interesting.

 

[sobrbiker883]

Re: Anyone bent an AR firing pin?

Suppression without gas regulation may be a culprit.

 

[ORD]

Re: Anyone bent an AR firing pin?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: sobrbiker883</div><div class="ubbcode-body">Suppression without gas regulation may be a culprit. </div></div>

+1. This, combined with hotter 69gr SMK loads, could result in the bend in your FP. Out of curiosity, was the FP retaining pin bent/mis-shapen/etc.?

Another possibility is that it could just be a bad FP. It happens sometimes if a mfg gets a part that is just weak or has some metalurgical flaw in it. Fortunately...FPs are cheap and easy to replace!

Out of curiosity, do you have any idea how long it has been like that? Or can you estimate from the last time your BCG was disassembled (when the FP was still straight) until now how many rounds you have through the rifle?

 

[Silverbullet2]

Re: Anyone bent an AR firing pin?

Guys,

I have about 400 rounds through this rifle. I have cleaned this rifle after every range trip. I usually run about 50-80 rounds per trip. I have not noticed the FP being bent before. The retaining pin is banana shaped. I have a Colt FP on it's way. I know they are quality units. I had never thought of a gas regulator on this rifle. I will bring it up to the builder of this rifle. It is a NON shrouded carrier. I have read that one needs an M-16 style carrier that IS shrouded for the ultimate in reliability. Thanks to all who have chimed in. I really like this rifle, and don't mind tweeking a few things to make it better. Jason

 

[tt350z]

Re: Anyone bent an AR firing pin?

Get a shrouded carrier. You don't "need" a M-16 carrier for it to be shrouded. An enhanced carrier is fully shrouded like the M-16 carrier but has a little bit less steel on the back of the carrier, see below.

I use an enhanced carrier vs the M-16 because I want less reciprocating weight. My rifle nose dives when I use a heavy buffer/carrier with a compensator on it, due to the extra mass going forward when RTB.

 

[Silverbullet2]

Re: Anyone bent an AR firing pin?

Update....
I brought the rifle to the smith that built it, and it was determined to be a bad firing pin. I have a Colt one on it's way, and will put that one in.
I just may replace the bolt carrier with a shrouded one, perhaps one of thoes nice Les Baer Custom ones.
Thanks, for all the ideas, and knowledge. JPG

 

[ORD]

Re: Anyone bent an AR firing pin?

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Silverbullet-2</div><div class="ubbcode-body">Update....
I brought the rifle to the smith that built it, and it was determined to be a bad firing pin. I have a Colt one on it's way, and will put that one in.
I just may replace the bolt carrier with a shrouded one, perhaps one of thoes nice Les Baer Custom ones.
Thanks, for all the ideas, and knowledge. JPG </div></div>

Glad you got it sorted out and that you'll have your replacement parts on hand soon.

Good luck!