Is this normal wear?

[alamo5000]

My gut tells me no but I could be wrong. This is the view looking inside the ejector port.

I tried to get some basic shots so you can see what I see.

It seems to me that this is excessive wear but I want to get opinions from ya'll first.

If it's not normal what could be causing it?

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What do you guys think? Is it anything to concern myself with?

A little background... the parts are a 10.5" Ballistic Advantage barrel. CMT UPUR3 upper. A Rainier Arms Phosphate BCG and a Griffin Snach CH.

It has somewhere near 1000 rounds through it, but probably a bit shy of that.

The gun runs fine for the most part but I have noticed that even if I have plenty of lubrication every now an again the bolt won't go forward into full battery and I have to recharge the handle. It might happen once or twice out of a mag or it might not happen at all. From the looks of that and where it is located that the bolt cam pin is causing it.

I will try to get some pics of the bolt up too because I have noticed some wear spots on it, but it doesn't seem like anything major, just a few wear spots where the phosphate has worn off. I am not a hard shooter but I do run this pistol/aka soon to be SBR a lot harder that I do my other gun and I put a lot more rounds through it too.

I am thinking my issue of the bolt not going into full battery and this could be related. Maybe something is binding? Dunno.

Please share opinions.

[alamo5000]

I just googled 'cam pin wear' and it seems like it is normal [wstupid]

[Slippers]

It eventually stops once enough material is removed. It's caused by the cam pin on the forward stroke of the bolt when it picks up a round from the magazine. The resistance of the cartridge being pushed out of the magazine presses the bolt rearward, which in turn causes it to engage the cam pin in the cam slot of the carrier.

[BoilerUp]

I can't quite tell what I'm looking at in the pictures. Is that wear just on the inside of upper receiver, on the opposite side from the ejection port?

[alamo5000]

It eventually stops once enough material is removed. It's caused by the cam pin on the forward stroke of the bolt when it picks up a round from the magazine. The resistance of the cartridge being pushed out of the magazine presses the bolt rearward, which in turn causes it to engage the cam pin in the cam slot of the carrier.

Thank you for the response. So the more I shoot it the smoother it should get then... hopefully.

I am only seeing a few issues... but based on what you just said it makes sense... my bolt isn't all the way locking forward from time to time... I am also noticing some scoring on the body of the spent shells. Most of them have nothing but some of them have a light score lengthwise...most though have nothing. It seems to be happening because of a slightly sluggish BCG... but I could be wrong on my guess.

As an experiment I changed the kind of lube I am using and personally I felt like I noticed a difference. I just ran a couple of mags with some plain old CLP and it seems like it is a lot smoother. I still have and use SEAL 1 but I am considering an all the way switch for the pistol/sbr... basically because it seems to require more frequent lubrication I might get a little squeeze bottle and fill it and put it in my pocket when I go to shoot. If I need a little then drop drop and back to business.

I haven't quite decided anything for sure yet but just in a preliminary test I seemed to notice a difference.

One thing that did happen though is when I changed lubes I was basically mag dumping and two seperate cases got jammed in the chamber... I was able to just pull them out by pulling on the CH, but the shells were unfired and bent pretty bad. Of course they were reloads so we shall see. I will keep an eye on it. I shot 90 rounds today and I will do a couple of mags every other day this coming up week to see if anything is persistent. Today was the first time ever I had bent cases...it could easily be from crappy brass though so I am not discounting that at all.

The main thing is my bolt won't go all the way into battery sometimes. That part is the main thing that I want to solve, but it seems like all these things can and maybe are related.

[alamo5000]

I can't quite tell what I'm looking at in the pictures. Is that wear just on the inside of upper receiver, on the opposite side from the ejection port?

Yes. Exactly. Look straight into the ejection port and there is wear but most of it is pretty cosmetic. Right at the end though near the barrel end it is pretty worn down.

[mustangfreek]

Was gonna say at first aero upper? Long inside joke thingy...lol

But that is quite a bit from the pics, but it could be the pics though...how does the cam pin look?

[DutyUse]

The Rock River we had years ago showed even more wear then yours. Not only did the upper have a score mark on both sides of the upper bcg track, but also where the CH rode as well. For the first month or two of owning the gun you could smell the anodizing burning off when you shot the gun or pulled back the CH a few times rapidly.

Didn't really matter which lube we used either. Eventually it stopped once the bearing surfaces became mated. The Colt 6920 did it as well but to a far lesser degree.

In my opinion, ARs are made to a "spec", but they can be plus or minus a thousand or two. If you get a few parts all on the plus side of the spec something has to give...

It never caused any malfunctions, just a little bit of annoyance.

[voodoo_man]

use it till it breaks and then buy something higher quality..

[BoilerUp]

IMO, no, this is not normal, but it is not unheard of either. I think the typical wear pattern is around the 5 and 7 o'clock positions (if looking head on at the bcg) as that is where the upper supports the weight of the BCG. As an experiment, I'd blacken the worn area and run a different BCG for a while to see if it wears the same way. That will tell you if it is the upper that is slightly out of spec or the BCG. You can of course continue to run what you have and it will eventually wear itself in, but make sure you install the cam pin the same way every time.

POF has a product that may help, too, if you want to throw money at the problem: https://www.rainierarms.com/pof-223-roller-cam-pin

I'd probably be tempted to go in and smooth and polish out the worn area of the upper and be done with it.

[BoilerUp]

use it till it breaks and then buy something higher quality..

Which component/manufacturer do you suggest is of insufficiently hight quality? The CMT upper or the RA BCG? Both RA and CMT have pretty good reputations for quality.

[voodoo_man]

Which component/manufacturer do you suggest is of insufficiently hight quality? The CMT upper or the RA BCG? Both RA and CMT have pretty good reputations for quality.

Never said they were of low or insufficient quality. But if its having an issue then there is obviously an issue.

[Fathom_Arms]

What kind of mags are you running?

[alamo5000]

What kind of mags are you running?

Magpul PMags. I have 20 and 30 rounders. Both are pretty new still.

[Stone]

More than likely its tolerance stacking between the cam pin and upper. Cam pin may be out of spec. try swapping it out with a different one. Sounds like its dragging enough to slow the bcg down and prevent it from going into battery. Run your guns wet. Lubrication is a significant factor on the coefficients of friction for phosphate coatings.

[alamo5000]

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[alamo5000]

From the pics you can see contact points and wear points. My other BCG (same brand same style) doesn't look like that. But again I don't shoot that other gun not even nearly as hard as I do this one.

Both sides of the gas key are wearing as well as other points...

[Dstrbdmedic167]

Keep shooting and just replace what breaks, if something breaks...


Sent from my iPhone using Tapatalk

[Stone]

Do you do a coat of oil in the upper as well?

[alamo5000]

Do you do a coat of oil in the upper as well?

Oh yes. I lube that sucker like crazy. The very first time I shot it I didn't do it enough, but every other time I have probably over done it.

I am thinking that I basically just need to keep on shooting the hell out of it until the surfaces all mate together better.

The only thing that I can complain about per se is that from time to time when that BCG hits a snag and has drag on it for whatever reason it won't go back into full battery. At which time I will have to stop, drop the mag, recharge... or whatever.... my upper doesn't have a forward assist on it but in this case I kind of wish it did. I would have been using the hell of out of it so far...

Well maybe not using the hell out of it but it would have saved me a minute of hassle on a few occasions.

[Stone]

Yep, like most have said just keep running it. It will eventually smooth out. Try another cam pin and see if that helps. I have been utterly opposed to uppers without an FA and your situation just solidifies my stance. Had that been a life or death stuation the outcome could have been catastrophic. Is it possible your ammo is under powered? Try some hotter 556 loads. What weight buffer are you using?

[alamo5000]

Yep, like most have said just keep running it. It will eventually smooth out. Try another cam pin and see if that helps. I have been utterly opposed to uppers without an FA and your situation just solidifies my stance. Is it possible your ammo is under powered? Try some hotter 556 loads. What weight buffer are you using?

I am using reloads for my ammo but I might go buy some store bought stuff to see if that makes a difference. It's very possible that it's under powered some. If it is it's not by much.

I don't know what weight buffer I am using. I am using a standard one I guess. I have always wondered about that though. I have heard other people talk about it but I have absolutely no experience with it or what it would do.

As for the FA...on my other rifle it also doesn't have one and I have yet to need it.

[alamo5000]

I went just now and shot 60 rounds and I think I have found the culprit on the failure to go to full battery. It happened a couple of times and after each time I ejected that shell and inspected it. Out if 60 rounds it happened twice.

Somebody gave me a bunch of brass that got mixed in with my regular brass... Apparently the brass is cheap, soft, has thin walls or whatever...but when the bolt would come forward it would pick up a case and as it made the trip up and into the chamber it was actually bending the brass over some, enough to cause it to not be anywhere near in spec to where it wouldn't all the way chamber.

Right at the shoulder of the case that leads up to the neck it was slightly bent over. I had some old lake city brass that I reloaded and I ran that and not a problem. Even the spent cases were not bent up.

99% sure it is not a gun problem but rather an ammo issue related to cheap brass.

I don't have a lot of it and most of it has been shot I don't know how many times so I will throw it all out and get something that is better. I have about 3000 same head stamped new and unfired Lake City brass that will work just fine in a pinch.

[alamo5000]

Another possible problem is that I have all my dies set up to reload my good 69gr ammo. Recently I bought 1000 55gr projectiles and I loaded those without changing anything. It is very possible that I am not seating the bullets deep enough.

[alamo5000]

Nope. Problem still not solved. Shot a mag and had one slightly bent case still.

I didn't keep it to take pictures but I googled a bit and found some that look sort of like mine. I still think it's the ammo not the gun but I could be wrong.

There are basically two things that are happening and it's not even happening with every round.

The first is the brass is bent so that it is slightly misshaped.

The image below is NOT MINE but it shows kind of what is happening although mine is not that bad.

http://i1124.photobucket.com/albums/l577/mrs-garcia123/Bent.jpg

Every now and again I am getting a case that gets 'bound up' and slightly bent which is causing the problem. It's not every time... I shot 90 rounds and it happened exactly 3 times.

I tried seating my bullets deeper on the last mag and that did seem to help some but this still happened.

The other thing that I see is that maybe the bolt is ever so slightly dragging on the cases so it's causing slight scratching on the body of the cases.

[mustangfreek]

What brass?

Even at that it would have to be very brittle or the like but still not where I would look.

Seating depth would change slightly I'm thinking, I know I have to reset my dies when going from heavies to like 55's

[Eric]

Have you run it with new factory ammo?

[alamo5000]

What brass?

Even at that it would have to be very brittle or the like but still not where I would look.

Seating depth would change slightly I'm thinking, I know I have to reset my dies when going from heavies to like 55's

I didn't save any of that brass (since it's only 1/30)...I don't know for sure that it is the brass now.

I did try changing the seating depth but at the end of the day the problem persists. Either the gun is cycling too fast or too slow which could possibly be any number of things. I am really not sure.


Have you run it with new factory ammo?

I have but it's been a while. I will go buy some factory stuff and see if it goes away with that or not. I've probably shot 3 or 400 factory rounds through it. probably more than that. I don't really recall any problems.

[JGifford]

Had a Noveske that did that.
I THINK! what was wrong with the part where it bent rounds, was the feed-lips had super sharp angles, and were shaving/digging into the brass and arresting forward movement, and acting as a fulcrum that bent the round.

It had a ton of other issues and Noveske just refunded me, minus the tax stamp, and I motored on. Never will know what ACTUALLY caused that.

[Former11B]

Another possible problem is that I have all my dies set up to reload my good 69gr ammo. Recently I bought 1000 55gr projectiles and I loaded those without changing anything. It is very possible that I am not seating the bullets deep enough.

You didn't check the OAL during and after loading the first round?

[alamo5000]

You didn't check the OAL during and after loading the first round?

I did. Of course I did. But I was thinking that maybe those bullets I bought were snagging and hanging up on the feed ramps or whatever. So I tested it seated just a smidgin deeper in an effort to isolate the problem.

I will try some factory ammo to see if for some reason my loads are occassionally under powered or not. That could be it as well. If I can run 100 rounds of factory ammo without a problem that will isolate the problem. If not then it might be the gas system being either under or over gassed... that said if that was the case I think it would be a more persistent problem. Not just 1 round out of a 30 round mag...

I really don't know the answer. I am scratching my head trying to isolate the problem.

[alamo5000]

I tried some factory ammo and a different mag. Not even a hint of a problem. I will do some more extensive testing when it stops raining.

[cjd3]

I tried some factory ammo and a different mag. Not even a hint of a problem. I will do some more extensive testing when it stops raining.
Maybe it needs to be rain tested.

[alamo5000]

Maybe it needs to be rain tested.

If I kept it up maybe I could have seen if a lightening bolt could have melted a suppressor [:D]