Is this normal wear?

[mow]

I recently received an LMT 16" upper assemby, it included the bolt group and charging handle.

I cleaned the rifle initially, then oiled it and shot the next day. After I got home I noticed some wear on the part where the bolt carrier mates with the gas tube, but just figured that it was breaking in. I shot it again last weekend. After shooting and while cleaning it I thought that it looked like there was more wear in the same area.

Today was the first day that I went out with anyone else that also had an AR to compare to and I am concerned about the wear indicated on the following pictures. Their AR's have absolutely no wear in that part on the bolt carrier that mates with the gas tube.

http://home.comcast.net/~gomowgo/images/bc.jpg

Please excuse the dirty pictures, but I wanted to take them before I cleaned it as it appears that metal from that part on the bolt carrier that mates with the gas tube has extremely abnormal wear on it. In the lengthwise photo notice the ridge that has been created.

http://home.comcast.net/~gomowgo/images/bc_length.jpg

And here is the inside of the upper, with the best shot I could get of the gas tube.

http://home.comcast.net/~gomowgo/images/upper_gas_tube.jpg

No issues have been encountered thus far with the rifle, other than I have accidentally double fed while trying to unload it at the end of the firing period. I clean it after every trip and am just wondering if this is something I should be concerned about...

[bu-bye]

I think ted may be on to something. The only thing that could cause that would be the charging handle. I have never seen that either.

[mow]

Ted, thank you for the nomeanclature:)

I do not see any bare metal on the charging handle.

http://home.comcast.net/~gomowgo/images/ch.jpg

I cannot get a good photo of the hole that the gas tube passes through, but I do not see any bare metal. Also It doesn not appear that the Bolt Carrier Key would go as far into it as the wear indicates, even when the bolt group is all the way forward...

Do you think this might make the rifle dangerous to shoot?

[glen avon]

key was made that way. if the key OD is that scraped and bright, so will be its mating partner.

your gas key is a sub-par POS and should be replaced with a good one.

since the staking is important, have it done by the factory.

might I suggest M1S, as it apparently can't get any worse that what you have....

[mow]

Buying new stuff and needing to send it to the factory rules! :eek:

[mow]

OK I cleaned it all up and I do not see any other bare metal ... weird huh? There was quite a bit of carbon build up on the bolt that I apparently hadn't noticed until today.

Is replacing the BCK (nomeanclature rules, thanks again Ted) something a novice could attempt without trashing it? If so would I need a torque wrench or anything other than a hex wrench to complete the job?

It looks like the bolts that hold it in place have been struck where the bolt meets the carrier ... to keep them tight possibly?

If this is not something a novice should attempt it would probably be best to go through my supplier and if that doesn't work out I will talk to LMT directly and send it in to them to get it done right.

From what I was told my upper was ready to ship but we were waiting for the bolt groups to arrive .... maybe the co. that produced the BCG rushed them and this is the result.

Thanks for the suggestions and insight Ted and glen.... calguns rules!

[glen avon]

you can stake it yourself but it's better if they do. they would rather see the whole thing anyways. it's not helpful when somebody comes in to exchange just one piece of something more complex - the context can be important to diagnosis, and sometimes it's easier and/or better to replace a whole subunit ot assembly. send LMT your bolt and bolt carrier, the whole shebang. let them do any staking, it does have to be done correctly. they will likely just swap out a whole new unit.

[mow]

Yeah, it would probably be quicker to deal with LMT directly and I don;t want to fix anything on the rifle seeing as it is almost new ... Think I'll call first and send them anything and everything they request (except my lower of course :p )

I will tell ya over and over again, I sure am glad caguns is around :D

[sv_sniper]

Mow, it's kind of strange. Let me ask LMT tomorrow. Mostlikely they would ask you ship it back for services. I will answer you later tomorrow or Wednesday.:)

[mltrading]

Yeah, it would probably be quicker to deal with LMT directly and I don;t want to fix anything on the rifle seeing as it is almost new ... Think I'll call first and send them anything and everything they request (except my lower of course :p )

I will tell ya over and over again, I sure am glad caguns is around :D

Mow, I have reported your situation to LMT already. Also sv_sniper has already sent you a return instruction. Plz check your e-mail. :)

[mow]

Thanks for starting the process for me. I tried calling but the gentleman referenced in the email had left for the day. I will call again tomorrow.

thanks again for starting the process.
mow

[mow]

OK so I got everything back earlier this week. LMT changed out the Bolt Carrier Key.

I went to the range today, and not one of the 40 rounds fired would eject on it's own. I had to pull the charging handle back everytime, and sometimes use the forward assist to get the next round to chamber. Sometimes it took quite a bit of effort to pull the charging handle back... like the spent round was stuck in the chamber. I started thinking maybe I didn;t clean it well enough the last time sooo...

I just brought it home and cleaned it. The BCK is not wearing like it had before, which I think is good news. I am not sure if the issue is a cleaning issue ... what else the issue could be? :confused:

I am going back out to the range tomorrow, hopefully the fouling I removed today will have my rifle ejecting and loading the next round without having to pull the charging hadle back everytime.

[Satex]

This sounds like a cleaning issue. AR15/M16 are notorious for people lubing the bolt, and then the lube sucks in filth and then it locks up. Anyone who used these rifles a lot will tell you that you should always have the bolt dry.

[mow]

So there should not be any lube where the bolt and bolt carrier touch?

I thought any place metal came into contact with metal that there should be lube ... :confused:

[xenophobe]

ARs need to be well lubricated. They should be stored dry, but when you're ready to shoot, gun oil is your friend.

That ridge is normal on an LMT...

[mow]

ARs need to be well lubricated. They should be stored dry, but when you're ready to shoot, gun oil is your friend.

That ridge is normal on an LMT...

OK now I am confused, stored dry? What about rust prevention?

I have cleaned and lubed the thing up. BCG, barrel, hammer ... when I go to shoot tomorrow, I'll run a dry patch through the barrel and when I go to fire hopefully she will cycle like she did before I sent the bolt group back to LMT.

I am not worried about the ridge at the end of the bolt carrier key, however the finish on the end of the BCK was wearing off and that was not a normal thing according to LMT.

[mow]

OK the fokker still isn't cycling! Now I am going to attempt gas tube surgery to see if there is anything blocking it. If not I will have to call LMT back :mad:

[mow]

Still not cycling!

I think LMT should have replaced the gas tube when they replaced the bolt carrier key. :confused: :mad: :eek:

Looks like I get to call them on Monday and find out what to do next.

[bonjing]

any update?

[mow]

I sent the entire upper back to LMT ... I am pretty sure that the initial bolt carrier key (that they replaced) wore down the gas tube enough that the replacement bolt carrier key could not get a good seal. Not sure if they are going to tell me what the issue is, it is slated to arrive at LMT on 5-31, so maybe they will update me at that point :confused:

[BigAL]

Just read the thread. Sorry about your LMT problems. I have an LMT upper that has never skipped a beat. Seems like their QC may have gotten spotty recently as demand has gone up. As far as lube goes, I run my AR fairly wet. I give the bolt a light coat of lube including the locking lugs. The gas rings get a good coat as does the bolt cam pin area and the exterior of the carrier where it contacts the upper. If i put the gun up for a while and it looks dry before I shoot it I will also squirt some lube into the two holes in the carrier and work the bolt back and forth a few times. ARs run dirty but by adding a few drops of oil will make the gun run for a very long time without actually cleaning it.

[mow]

Whats funny is before I sent this in for what was apparently a cosmetic issue with the bolt carrier key (the black finish wore off from the gases ? This is what I was told. :confused: ) the upper functioned flawlessly, again except for the time when I was trying to unload the rifle at a range after a cease fire was called and in my haste I mistakenly double fed a round.

Today I received an email from LMT stating that they received it and did not notice any normal wear and that they would be sending it back. I replied that the upper functioned flawlessly prior to getting the key changed out and that while the wear doesn't look out of the norm that the upper will not cycle after receiving it back with the new carier key.

They emailed me back saying they would test fire it tomorrow.

Does anyone know if there could be another issue for why it would not be cycling?

Please keep in mind all of the stuff posted prior, the rifle was cleaned and oiled, the gas tubed was verified to be unobstructed, the key was replaced and prior to the key replacement the rifle cycled, after receiving the updated bolt carrier key the rifle will not cycle.

Any insight or additional info I could provide to LMT tomorrow would be helpful.

[mow]

OK everyone don't flood me with answers or suggestions :D

I heard back from LMT today. Apparently the carrier key that was replaced didn't have the hole that goes through to the bolt carrier? I don't know what he is talking about but I am glad the issue has been resolved! He said he had never seen such a thing, that he would switch out the carrier key again and test fire it tomorrow morning and if all goes he'll ship it out 2 day air tomorrow!

Woopee I get to go to the range and throw lead down range!

Sure it took over a month to rectify but at least this issue appears to be behind me. Three cheers for LMT making it right!

[mow]

Just got it back, I am off to the range :p

Hopefully it cycles and I don't notice any abnormal wear on the gas key.

[mow]

w00t:D

Back to normal! The weird part is out of the remington, black hills and wollf rounds that I shot, the wolf grouped the best:confused:

I have lots more ammo to try this weekend. I am just happy that my rifle cycled properly.

4 replies to myself ... w00t:D