Anomaly on my AR. Is this normal?

[RavenVT100]

Anomaly on my AR. (Updated with pics)

Yet another "is this normal?" thread. I'm going to post pictures of this anomaly but it wont be until tonight.

I have a Bushmaster 20" AR. It's had about 1000 rounds through it, and I've started to notice a patch inside the upper where the finish has chipped off to bare metal. It's on the side of the slot that the charging handle fits into, close to the chamber end. It's about an inch away from where the gas tube protrudes. The only reason it alarmed me is because the surface is slightly rough where the finish has chipped away.

I know the upper is made of aluminum, and that it is going to "wear in" as the rifle breaks in. I assume this is normal?

 

[Commissar Gribb]

I'm by no means an AR expert, but the area you're describing sounds like the part where the bolt cam rotates when the barrel locks into position. you may want to examine your rotating cam/bolt carrier for burrs/ground surfaces etc. I've never had a problem like that with my AR- mostly loose gas keys** either way, as long as it operates correctly, I dont see that being a problem.

**BTW I got that fixed

 

[RavenVT100]

Yeah, I don't see it being a problem either, but I'm not a master gunsmith or AR armorer so it's better safe than sorry. I'll have to see if the location in question is anywhere near where the key ends up rotating. The wear/chipping is right above that little slot that the charging handle fits into, so it could very well be the camming that causes it.

 

[g56]

It has been reported that Bushmaster has been having some problems with their anodizing process, this may, or may not be your problem.

 

[RavenVT100]

Here's a picture of the worn area in question:

 

[Bartholomew Roberts]

That doesn't look like normal wear to me. It looks like the park is flaking off. From a functional standpoint, I don't think it will affect weapon function any; but it isn't something I would normally expect to see and I would expect Bushmaster to correct the problem if I asked.

 

[Mulliga]

Argh! My AR looks like that, too. :banghead: It's a Bushmaster with 3000+ rounds through it - no reliability problems, aside from sometimes not locking back on the last round of my mags (I believe this is a mag issue, since I keep 'em fully loaded all the time and I regularly cycle ammo through them).

 

[yorec]

Haven't seen anything like that yet...

After shooting is there brass/copper residue on and around the wear area?

If not, I'd suspect it's a finish problem in a stress spot. If so - brass is going where it should not during the action's cycle. (load or eject)

From the looks of the pic, I'm guessing a finish problem.

 

[RavenVT100]

I need to know what problems might be caused by this, if any. I don't want to risk damage to the rifle.

Edit: No copper marks or evidence of brass getting in there. Brass is ejecting as normal.

 

[Bullet]

I would call Bushmaster.

 

[buttrap]

just wait till you get some rounds tru that gun. If its not putting gouges in the alum I would not worry about.

 

[Jeff White]

Looks like the adonizing is wearing off. Bushmaster should fix it. Before I retired from the Army we received some brand new M16A2s built by FN that had a similar problem on the lower receivers.

Jeff

 

[Bartholomew Roberts]

I need to know what problems might be caused by this, if any. I don't want to risk damage to the rifle.

I would contact Bushmaster and ask them; but assuming a worst case scenario that the actual anodized surface of the aluminium has flaked off, it will mean that the receiver has a softer surface hardness in that spot and is more subject to corrosion.

From a practical perspective, unless you are beating that spot with small hammers or dunking the rifle in a salt-water bath on a daily basis, I would be skeptical whether it would affect you much; but I've never had the issue long-term so it would probably be better to ask Bushmaster.

 

[RavenVT100]

I'm going to call them today.

I have a sneaking suspicion that I'll get the "Oh, that's a normal part of wear and tear" response. This is what occurred when I asked about my SIG P229s finish wear on the slide (which happens to be aluminum as well).

In any case, I will report what their response is.

 

[Chipperman]

That's a great photo. Email it to them so they can see specifically what you are talking about.

Mine do not have that wear.

 

[RavenVT100]

Thanks, chipperman. My camera can see finer details than most humans. Whenever I see something odd on my firearms or even in my bores, I can hit it with the digicam and get a nice high-res picture to examine at my leisure.

EDIT:

I had Bushmaster look at the pic. They say that occasionally, there can be some raised areas on the finish of new parts. This will cause some wear, but the wear will stop once the parts break in. They said to send it to them if it gets worse.

 

[Chipperman]

Sounds like they are taking a middle-of-the-road approach.

They really don't feel like fixing it because it's not a functional problem, but they will if you send it to them.

Sounds reasonable.