M*CARBO Brotherhood

MCARBO Ruger PCC Bolt Head Pin Failure

Discovered this last evening while cleaning for today’s range trip. I’ve got 2250 rounds through my Ruger PCC with essentially no issues or failures. My factory pins were showing some wear but this did not affect performance of the firearm. I purchased the MCARBO pins with the extractor at the end of last year and decided to install them while doing a complete tear down and de-scuzz of the PCC in February of this year. Anyway, I did another complete tear down last evening and discovered this…

Not sure when it happened or what happened to the piece that broke off, but the gun never malfunctioned. This happened at some point within 375 rounds as that’s the total I’ve shot since installation. Could have been less than that for all I know (and likely was given the burnishing on the fractured edge). The only thing that irritates me about this is that the piece that broke off clearly chewed up the inside top of my receiver before ejecting itself at some point. I put the old pins back in and she ran without a hitch today. I’m sure MCARBO will cover the parts though I am wondering if I actually want to install them…

The purpose of this post is just an FYI, putting the information out there for reference.

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Totally looks like a fatigue fracture. Maybe a metallurgy issue?
That really sucks that it damaged your Rec err over too.

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I would guess so, after 375 rounds (or less) it would seem more likely due to a defect in the metal over actual fatigue from repeated use and stress. It does make me wonder if it’s a factor of using a harder material. Harder materials tend to be more brittle, generally speaking. Maybe the factory pins were softer for a reason…I dunno…

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@chilipepper

giphy

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Could be, that would make sense too. Could have been a flaw in the material as well.
I wonder what MCARBO will have to say?

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I just installed mine… I have less than 100 rounds though it since… I wonder if I should check now…

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So far so good… but only 75 0r so on the pins… 2+ K on the carbine did the recoil Pkg extractor, pins. trigger and SS pins

I do want to say it ran really nice, the buffer worked well the trigger is nice and it extracted perfectly.

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Well, I hope for everyone’s sake it’s just a defect in that one pin.

The recoil buffer thing didn’t excite me much, took a pass on that one and the stock one has held up like a champ so far. Only indication it’s been used for 2250 rounds is a slight indentation of the bolt block profile in the forward face of it. I did replace the spring retainer with MCARBOs metal one as the plastic factory part was starting to get a little gnarly from removal when doing thorough cleanings. I did go for the trigger, though I had no issues with the stock one aside from the fact that it’s plastic. I like the idea of the SS pins but haven’t bothered yet, ain’t broke don’t fix mentality I suppose.

I quite like all of my firearms but I think the PC Carbine has given me more smiles than any other. It’s got the most rounds by far through it, hits whatever I look at and has been 100% reliable. Hell, it even ate part of that bolt pin and kept on chuggin’…I should call it “juggernaut”. :grinning:

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Despite having 2 very good AR’s I like my PC Carbine the best too!
I has been close to perfect, I can hit like crazy with it which makes it super fun for me.
I have a nice padded elastic sling for carrying. Great gun and untill just now it was screaming cheap to shoot.

Oh I put the stick on foamy cheek rest and I like that too, I’ll Like it even more at -20 below

I put the buffer deal in cause I got a bunch of old Paki surp Sub gun ammo that is hot AF
and now seems to be the time to shoot that up

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Heard that, can I get an “Amen”?

Haven’t seen -20 below here in decades but I would imagine that’d be nice.

Heard that, too. I’ve got very few boxes of Speer Lawman I’ve been desperately trying to hang on to, opting instead to shoot up the smattering of 150gr flat nose Federal Syntech I’ve got…all the while waiting for HSL to fulfill my 9mm reman order (should’ve purchased more than one :thinking:). At least they’ve got my .223 Remy on the way…

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amen

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I had the same thing happen. Contacted MCARBO and they sent me replacements. According to customer service, they had a bad batch.

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Well that clears up that little mystery.
@chilipepper

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Indeed it does, defective parts for the win!

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So can you repair the damage to the receiver, maybe dress the damage?

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I noticed Gouging in My receiver at the rearward travel point… I took a photo but it doesn’t show the damage it just looks worn on the photo and this was from the Original pins.

I have a similar round count to chili.

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I dressed it with a little bit of fine sand paper to knock down any potential highs and cleaned up the edges of the recoil spring channel. Not much else I can do short of replacing the receiver (which at this point would probably be overkill - plus this part is technically the gun, serialized). I suppose the damage could lead to premature/accelerated wear on the receiver but only time will tell on that one. I will likely be doing thorough tear downs and cleaning more frequently to keep an eye on things and to lube the area more often. I didn’t shoot it much yesterday but she seemed to run fine.

I might just opt for a little gun grease in lieu of oil at that location, might help.

Mine looks a bit worse than that now, I’m afraid…though yours looks about like mine did prior to the pin discovery.

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I think some Lucas red and tacky on the pin heads is in order and polish out the metal to remove the stress risers from the gouging.

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Pretty much this. I need to get more polish (fresh out) and while I do have some TW25b, I’ve been looking at something more substantial for use with my SIG P22x slide rails as well. Two birds, one stone. If that area is smoothed and lubed enough, I think it will be alright. It isn’t actually an area where the bolt assembly rides or bears on, I think it just gets worn from the bolt head/pins shifting a little on use. That whole assembly has a bit of movement in it, which I suspect is what causes the wear in your photo. Mine’s looking more like it did 5k+ rounds at the moment…

Outta likes. Again.

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You will have a very hard time beating Lucas red and tacky. I use it on my farm equip which gets Beat to F and it holds up @ 5.00 a 12 oz tube.

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