AR maintenance question

[rentalguy1]

I put a lot of rounds downrange in various settings, but that was back in the early 90's. Now I have my own AR (Rock River Arms CAR-A4) that I have put a few hundred rounds through, and I noticed something that I've never seen before when I cleaned it after my last range trip. I remember seeing a wear mark on the bolt cam pin that ran the full circumference on every AR I ever maintained. My AR has this wear mark, too, but on one side, there is a gouge in the center of the wear mark. It is only on the one side, and runs the enter length of the arc. It is about 1mm deep, and looks like something has dug in from the bottom, and pushed the metal towards the top of the cam. Any ideas if this is just normal wear, or do I have some type of malfunction? What should I be looking for that could be causing this? It has always had Federal .223 55GR ran through it (about 200-250 rounds) and it was brand new when I bought it.

[molonlabetn]

Picture?

[rentalguy1]

Tried to take a pic, but it came out really bad. Let me try again...

[rentalguy1]

Yeah, it's just not gonna work with my camera. You can see the wear mark, but I can't get close enough to show the gouge. It is right in the center of the wear mark, following the same arc. It may be normal wear, and I just don't remember it.

[andersmg]

If your camera has a "macro" setting, that is what you need to use to shoot close up shots, but if it doesn't then you won't have that ability with that particular camera.

Sorry, I can't help you with the wear question...

[rentalguy1]

no macro on the camera...it's a older, cheap one. I'm gonna go hit up the gun shop for a new cam pin. I'd like to have a spare on hand, so I can replace it if i feel the gouge is getting too dangerous. I have checked the entire circumference of the pin with a eye loupe, and it isn't cracked.

[peejman]

For the pic... If your camera is more than 2MP, back away from the part until you get a sharp picture. Then crop the image down to show only the part.

[Guest RangeMstr]

no macro on the camera...it's a older, cheap one. I'm gonna go hit up the gun shop for a new cam pin. I'd like to have a spare on hand, so I can replace it if i feel the gouge is getting too dangerous. I have checked the entire circumference of the pin with a eye loupe, and it isn't cracked.

It's most likely a QC oversight during manufacture. I'll bet RRA would send you a replacement cam pin for free. You need to build up a spare parts kit anyway. Nothing special, just the "usual suspects"; firing pin, disco, disco spring, extractor, extractor spring and insert, gas rings, cam pin, etc.

[rentalguy1]

I talked to RRA, and they said it is normal to get a stair step worn into the cam. They said I should check the carrier for burrs, which I've done, and rotate the cam 180* for even wear. If the gouge gets worse, and does not smooth out into a stair step, then it needs to be replaced and the bolt needs to be looked at. They said I could send the rifle in to be looked at, but since Taurus has had my wife's PT709 for 6 weeks now (and saying the parts my take another 2 weeks to get), I declined at this point. I don't want my AR to be gone for 2 months. I'll keep a eye on it and update here after I shoot it again.

[enfield]

Normal wear for RRA, maybe. I think they may have a hardness problem, whether they recognize/admit it or not. I'd replace the cam with a non-RRA part and see if the wear re-occurs. It's too early to tell if the problem (and there is a problem, IMHO) is with the cam or the carrier.

I never saw wear like that on a military M-16, and there's no telling how many thousands of rounds mine went through.

[molonlabetn]

Yeah, that wear looks like something is out of spec...

[rentalguy1]

I'm with you guys on this. I don't recall anything like this on any of my military M-16's, and I shot both the A1 and A2. A shiny, wear mark, yes, but a gouge no. I am going to replace it with a roller cam(?) and re-inspect the carrier and see what happens.

[gotigers]

cam pins are cheap. replace. Bravo co. has them for $5.

[rentalguy1]

Can't see just replacing the pic without correcting the underlying problem, though...whatever that turns out to be.

[Guest Todd@CIS]

Normal wear for RRA, maybe. I think they may have a hardness problem, whether they recognize/admit it or not. I'd replace the cam with a non-RRA part and see if the wear re-occurs. It's too early to tell if the problem (and there is a problem, IMHO) is with the cam or the carrier.

I never saw wear like that on a military M-16, and there's no telling how many thousands of rounds mine went through.

+1

My RRA has about 3500 through it and doesn't have this problem.

Can't see just replacing the pic without correcting the underlying problem, though...whatever that turns out to be.

The cam pin may be the problem. Replace it (as stated, $5) and then if the problem continues, move on to more expensive "fixes."