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So I bought a 16.1" Upper with A2 flashhider, LMT Enhanced bolt, LMT Enhanced Carrier, and PRI Gas Buster Charging handle.

In my plans to have it ready for the last Virginia Black Rifle Day 3-gun I cleaned it off, lubed it up and went to break it in with a couple hundred rounds of IMI Q3131a.

First mag, had a double feed on round 3 & 4.  OK, no sweat....new upper.  Give it some time.

Second mag, double feeds and FTE's.  Hard jams too....one spent case in chamber one wedged in behind it.

Kept at it for awhile.....finally had a super hard jam with the spent case getting locked in concert with the back of the charging handle's leading edge.  That one was a doozie.....

So I employ the help of two pretty knowledgable shooters and AR guys -- FMJunkie and VA-Gunnut.

We start by trying different mags...mags that work well in Rob's rifle.  No dice.  They run about 5 rounds and it jams up again.  Doublefeeds, followed by FTE's...

OK, so we try some more...nothing is working....let's try a different lower....

Nope same symptoms....possibly short stroking, doublefeeds, FTE's....

OK, let's try someone else's carrier....problem is a little better but not much....get to run about 30rds then second mag is back to the same old.

OK, let's try someone else's entire bolt and carrier assembly in the LMT upper.....problem goes away for 60rds so I think we may have the upper broken in/or have found the solution.  Drop the LMT bolt and carrier back in and run about 90rds......then hard jam after hard jam.

{disassemble LMT carrier and bolt and brush it off, lube it up again.....spend about an hour trying to fix a major reassembly fuck-up on my part }

Get the rifle back together and give it another go....some FTE's, some doublefeeds, but now we are getting 3 or 4 mags at a time.....

Maybe 400rds through at this point......

Take the bolt and such back out clean it again, blast the upper with some Action Cleaner, re-lube and go again.

By 600rds it's working...........ran 6 mags straight....nothing wrong.

Next day...runs fine for the three gun and most of the day......I think it is possibly fixed....but it jams at the end of the day...so I put it away.

I clean it up at home and take it out to the range for some more "testing" in preparation for Blackwater.  Gun runs about 300rds with no hiccups but starts to develop a FTE, stovepipe issue a little after that....no sweat......maybe just needs to be cleaned a bit.....clean it, runs pretty well....

Blackwater -- find out that an out-of-spec CAR buffer spring is in need of replacement.  Replace it when the FTE's and doublefeeds become unbearable at the end of Carbine Day 1.  Carbine Day 2.....rifle is almost in an un-useable condition.  Can't go more than 3 or 4 mags without a major failure.

Post Blackwater:  Change buffers, buffer springs and clean upper WELL.......take to range with RRA M4-type upper, another lower LMT upper and some tools.

First mag is doublefeed, so I set it aside to test in the "control" rifle.  Second mag, same....3rd mag same......swap to the RRA upper run same mags.......no issues.  Hmm....

Start swapping parts and mags to find out what is working and what isn't......here is what I found:


LMT bolt with LMT carrier in LMT upper on CAR lower, not good.
LMT bolt with RRA carrier in LMT upper on CAR lower, not good.
RRA bolt with LMT carrier in LMT upper on CAR lower, not good.
RRA bolt in RRA carrier in LMT upper on CAR lower, not good.

LMT bolt with RRA carrier in LMT upper on A2 lower, not good.
RRA bolt with LMT carrier in LMT upper on A2 lower, not good.
LMT bolt with LMT carrier in LMT upper on A2 lower, not good.
RRA bolt in RRA carrier in LMT upper on A2 lower, not good.

LMT bolt with RRA carrier in RRA upper on CAR lower lower, no problems.
RRA bolt with LMT carrier in RRA upper on CAR lower lower, no problems.
LMT bolt with LMT carrier in RRA upper on CAR lower lower, no problems.
RRA bolt in RRA carrier in RRA upper on CAR lower lower, no problems.

LMT bolt with RRA carrier in RRA upper on A2 lower, no problems.
RRA bolt with LMT carrier in RRA upper on A2 lower, no problems.
LMT bolt with LMT carrier in RRA upper on A2 lower, no problems.
RRA bolt in RRA carrier in RRA upper on A2 lower, no problems.

Now this was not scientific, nor did I run the same amount of rounds through each.  "No problems" means it didn't jam and ran the rounds down range as expected.  "Not good" means it jammed in some manner that required a mag drop, a screwdriver, or some other intervention on my part to clear the jam.

I am at a loss at this point.  Called Chip Witt.  Says the ammo is at fault as the enhanced bolt and carrier were designed and spec'ed around the M855 round.  That bolt and carrier combo seem to work OK in the RRA upper using Q3131a, but still not totally discounting it.  I think there may be a gas system problem with the upper that is possibly changing with the upper heating up and cooling down....maybe effecting gas impulse....just not sure......I am not an AR gunsmith....

At this point I need to clean the upper and send it in to Chip @ LMT....I was so disgusted when I got home it's still sitting, dirty, on my work bench.

I believe that LMT will take care of me, this is why I got an LMT, because they apparently stand behind their products.....

My only concern is that when I send it back, if they test it with M855 and the upper works fine, as it has for me on occasion, what do I do???  I don't shoot M855 and have a fair amount of Q3131a in the house as well as 2000 rounds of XM193 on order.....

I understand that if it doesn't fail at LMT then they can't really help, but that doesn't mean it's gonna work when I get it home....

I am not bashing LMT, I think this product and all the others I have seen are top quality pieces and I am even going to get a 10.5" LMT upper {with Colt M16 b/bc} for my inbound M16.  I have seen the uppers run on other guys' rifles.  So I know that there is something wrong with this upper/bolt/carrier combo.....

Any thoughts?  I will likely end up selling off all my semi-auto AR's when the M16 gets here, but that is a couple months out.....I was hoping to keep this upper as well as the 10.5 LMT for F/A blasting......

Quoted: Man, I sorry to hear about all your troubles.  Hopefully LMT will step up and get it straightened out.  Keep us posted!

The only thing that made me pause was the ammo issue......I guess that Q3131a and XM193 is now classified as "plinking" ammo....

From everything I heard from Chip I think they are going to give me a fair attempt at fixing "it" -- whatever "it" is......

Quoted: I'll give you $100 for the complete upper, "as is!"

Sure, come and pick it up.........

I will part it out if it comes to selling it......barrel, upper, bolt, carrier, etc.....

Quoted: Any M855 in stock? You have the problem isolated to the upper itself, it seems. Hard to believe it won't run right with XM193... I'm surprised you took it to Blackwater. An upper with that many issues, I wouldn't have.

Some of the problems I faced at Blackwater were lower related.....bad "shade tree" CAR spring fix....

However, after switching CAR buffer springs the problems persisted.  I was able to make almost the entire first day with no issues.  Towards the end it just kind of "died".....all at once.

The second day was intermittent failures......I believe I came away with a BETTER and solid understanding of how to clear the rifle and keep on going....was a VERY valuable training tool IMO....

I had a backup upper that I could have deployed if necessary.  It was intermittent enough that it never did.....

Quoted: Are you using a standard CAR buffer or the H-Buffer?

I am NOW using the Colt H-buffer.  For the first part of the story there was a standard CAR buffer in the rifle....for the last part, where I switched and swapped with the RRA it had an H-Buffer.

Quoted: Shouldn't have to do anything, it's a brand new upper! Let LMT fix it.

Well shit, it's about 2500rds down the pipe now.....at least 600 to "break it in" at least 300 to function test it before Blackwater....at least 1200 at Blackwater....at least 300 to function test it after Blackwater.

Quoted: SHIVAN, I'm sorry to hear that you've had so much trouble. It just makes me more thankfull that my LMT upper seems to be so reliable. I'm sure LMT will make it right.

Oh, as with all manufacturers sometimes things get screwed up.....I have seen C4iGrant's LMT run all day long on two consecutive days.  I've seen two others on M16's run all day long on full auto.

I have no doubt that it is probably just a silly thing like a partially blocked gas tube, or mis-drilled gas port, or shitty gas block -- or maybe just a bad bolt/carrier combo for my intended use.

If the bolt and carrier are meant for M855 it may find itself on the EE soon after LMT gives it a clean bill of health.  It is a VERY nice setup....but if design spec is design spec then someone with M855 stashs of ammo will get a very nice setup.....

I am not pressed to get the upper back, so long as the wait is reasonable and the result is favorable....

From every indication, it will be handled properly -- like most companies do.....

No sweat, I am used to waiting on custom work now, so this should be no sweat.

My biggest fear is that it will work fine for them with M855 and they send it back with no changes....I can't blame them, but the entire upper will find it's way to the EE then......QUALITY piece just not for me.  

As soon as I get off my ass and clean it I will be sending it in......

Quoted: Quoted: So I employ the help of two pretty knowledgable shooters and AR guys -- FMJunkie and VA-Gunnut. OK, let's try someone else's carrier....problem is a little better but not much....get to run about 30rds then second mag is back to the same old. OK, let's try someone else's entire bolt and carrier assembly in the LMT upper.....problem goes away for 60rds so I think we may have the upper broken in/or have found the solution.  Drop the LMT bolt and carrier back in and run about 90rds......then hard jam after hard jam. {disassemble LMT carrier and bolt and brush it off, lube it up again.....spend about an hour trying to fix a major reassembly fuck-up on my part } I was there helping too. Sorry to hear you haven't gotten everything worked out yet.

Yes, by the time I was done we had several folks peering in......

Quoted: Quoted: Y'all got me all nervous!  I've got a new LMT upper and lower sitting in the safe, but it'll be months before I get the project finished and go out to give it a run.  I just pray it was a freak situation for LMT products, they're supposed to be one of the best! I wouldn't worry about it, like SHIVAN said, all manufacturers have problems from time to time, that's just life. A friend of mine and myself are running LMT uppers with 100% reliability so far, I'm even using the LMT enhaced bolt in the LMT std carrier as well. eta: I'm also using the 55gr Q3131A with my setup, zero problems to date.

Exactly, my story is one story.......even with 10 more problems listed on this board you are likely talking less than a 1% total failure rate.

Gee, I remember posting about a problem with an LMT enhanced bolt a couple of months ago, and being asked if my post had something to do with the ongoing legal battle between LMT and L-W!
Ring any bells?

Quoted: Gee, I remember posting about a problem with an LMT enhanced bolt a couple of months ago, and being asked if my post had something to do with the ongoing legal battle between LMT and L-W! Ring any bells?

It does.  Bolt and carrier apparently work in the RRA upper and on both lowers.

Thread

I'll let LMT tell me whether or not their bolt is out of spec.....

I'm not trying to say that your bolt is the problem, Ed.  I just find it darkly amusing that someone who accused me of an ulterior motive for posting about a problem with an LMT product should have a similar problem later.
Don't take it too seriously, it's not meant to be.

Quoted: I'm not trying to say that your bolt is the problem, Ed.  I just find it darkly amusing that someone who accused me of an ulterior motive for posting about a problem with an LMT product should have a similar problem later. Don't take it too seriously, it's not meant to be.

Karma is a bitch.......

I hate to disappoint you all, but it was just as it appeared, a real problem that arose in the midst of a customer's build, and cost me a lot of time and ammo to resolve.

Quoted: Quoted: I hate to disappoint you all, but it was just as it appeared, a real problem that arose in the midst of a customer's build, and cost me a lot of time and ammo to resolve. I was just giving you some gentle ribbing.  BTW, any idea when KAC is going to release an enhnced bolt/carrier for the commercial market?

I'm afraid not. As a matter of fact, when my current inventory is exhausted, I will no longer sell their products. There will be an explanation of the reasons on my web site soon.

Quoted: SHIVAN and Bandit-ExcaliburArms - I would encourage both of you to review my thread on problems with the LMT enhanced bolt & LMT standard carrier.  3 pages, but a good read. Chip also gave me the bs about 55 grain bullets not having enough power to work the enhanced bolt. www.ar15.com/forums/topic.html?b=3&f=118&t=192685

I have read it......I posted mine separately so as not to cloud yours......

LMT was asked by the Govt to make their products around the M855. So they did and this is where the problem is (for the Civilian market). Most folks cannot afford (or find M855) ammo. Does this mean that the enhanced bolt won't work with XM193? No it doesn't, but the chance of it not working will go up. I run ALL LMT products (enhanced bolt, standard bolt, 2 stage trigger, lower, upper, sopmod stock, receiver ext, H buffer, car spring, etc) and everything works perfectly to say the least (and yes I have witnesses, Ed being one of them). Does LMT have QC problems from time to time? Yes they do. If a human makes it then there can be a mistake.  The good thing is that LMT is a stand up company and will fix their error....


C4

Thanks for the offer dport  I'll just send it back and let them test it.....