Confirm Action

Are you sure you wish to do this?

Confirm Cancel
Member Login
Posted: 5/16/2004 11:59:29 AM EDT
[Last Edit: 9/15/2004 1:05:52 PM EDT by meateater]
i need info or help, after about 2k rounds my new and freakin expensive l.m.t. b.c.g.
has failed to extract. the pin that holds the extractor is really loose. usually i need to punch out the pin on a regular bolt. the lmt pin just falls right out. the springs for some reason feels "dead". it just doen't hold the shell casing when extracting! i have cleaned and checked out the bolt, there is no damage to the bolt as far as i can tell. the extractor moves by finger preassure, so it,s not "locked up"
i have had my lmt bcg for about 3 mos. now and i am really disappointed with it. i think i'll send it back and get my $300.00 back! i threw in my old usgi bolt and it extracts perfectly. i purchased the lmt bcg because i had heard it is a far superior product.(just an isolated case with me?) and it was the reliability i was after. anybody else have the same problem? i have a 16" 1:7 chrome lined bbl and chamber 5.56. i know its not my upper or mags. i was susing imi m855 and l.c. xm193 round it would not extract either of them. heeeeellllppp!

thanks, meat
p.s. good thing i always carry a spare bolt, because if it were a" real" situation and not just at the range, i'd be dead.
Link Posted: 5/16/2004 12:04:15 PM EDT

I threw in my old usgi bolt and it extracts perfectly.

There's your answer from me.

Most, not all but most, of the "enhanced" parts out there are a solution to a problem that doesn't exist.

The standard USGI bolt carrier group parts work perfectly as you admitted. My suggestion is to get your money back for the LMT parts if that's possible.

Link Posted: 5/16/2004 12:14:19 PM EDT
I too was thinking of getting the LMT bolt group. And my main concern was reliability. Now maybe I'll wait to see what else surfaces. Who was the manufacture of the standard USGI bolt carrier group you had spoken of, was it Colt?

Link Posted: 5/16/2004 12:26:37 PM EDT
i puchased my usgi bolt from fulton armory. but i'm sure many of our industry partners have them in stock. i'm not sure if my f.t.e. problem is just isolated to this bolt. maybe it just passed through q.c. i dont know, but i'm bummed.when i first got my lmt bcg it was fine. about at 1.5k rounds is when the f.t.e. prob appeared. i thought my m4gery just needed a good cleaning. thoroughly cleaned my m4gery and shot the first round at the range today and f.t.e. after about a 100 rounds of f.t.e, dropped in my old and used usgi bolt and shot the rest of the day with no failures. i hope its just isolated with my lmt bolt, i dont know if im going to send it back for repair or get my money back if i can. we'll see

Link Posted: 5/16/2004 12:34:07 PM EDT

You might want to take a look at my thread on a bolt carrier issue that causes failures....


This might apply to you.

Link Posted: 5/16/2004 12:40:31 PM EDT
thanks and i have read your post, i do not feel at this time my f.t.e. problems are coming from the carrier "catching up". the bolt simply does not "retain" the shell casing before extraction. i.e. the old shell gets stuck in the chamber because the extraction has not been completed before the next round is cycled.
Link Posted: 5/16/2004 12:56:10 PM EDT
Link Posted: 5/16/2004 1:40:49 PM EDT
you are the best! it's industry partners like you make all the money i spend worth while.
i fully understand that like all manufacturers some do have a tendency to pass q.c.
i will give chip a call on mon. i'll let you know what the response is from lmt.
just a curiosity grant, not that i can afford it right now, you still have access to the authentic spr mk0
you posted earlier? bloodbank will only let me donate so much blood at a time[:)}

Link Posted: 5/16/2004 2:13:22 PM EDT

Call LMT (Ask for Chip Witt) 309-787-7193

That's the fax #, you mean 787-7151.

Actually, there's a duplicate thread over on AR Discussions, might help?
Link Posted: 5/16/2004 2:55:23 PM EDT
Link Posted: 5/16/2004 3:28:49 PM EDT
[Last Edit: 5/16/2004 3:31:46 PM EDT by Green0]
My guess would be LMT's parts are perfect. The springs probably need to be changed.

They may have been ground too short, or gotten too hot and taken a set. (springs aren't immune to damage, it just takes a lot of abuse to get them hot enough.)

By the way if you worry about real situations get a handgun, any competent enemy will be able to take you out in the time it takes you to diagnose the problem, break down your rifle, change out the bolt and put it back together.

The bolt is a good idea for getting the weapon back on line after you are in the clear.
Link Posted: 5/17/2004 2:01:02 AM EDT
Hey Meateater, if it makes you feel any better I had the same thing happen to a standard Colt bolt. After about 500 rounds the spring just turned to mush and quit extracting. A new spring was all it took to get it back into operational status.

Link Posted: 5/17/2004 5:17:13 AM EDT
Grant or any other LMT dealers.Can you get a extra set of springs for the enhanced bolt,to keep on hand as spares??

If so how much are they.I would like to have an extra set.

Link Posted: 5/17/2004 5:54:59 AM EDT
Link Posted: 5/17/2004 6:51:07 AM EDT
[Last Edit: 5/17/2004 6:51:38 AM EDT by greentips]
My friend was using a LMT bolt to test fire. Shot great in the first two sessions and then all a sudden it jsut wont' shoot worth a damn anymore. Swap the bolt out for a new Armalite and everything back to normal.
Link Posted: 5/17/2004 7:30:13 AM EDT
[Last Edit: 5/17/2004 7:30:54 AM EDT by Green0]
The LMT bolt carriers do have a third gas hole. That means it requires more gas to cycle them at the same speed as a standard carrier.

They are great for suppressed weapons or weapons that have high use or military use (erroded ports) but may not cycle in a range queen AR.

The springs taking a crap would piss me off as they are marketed to last 100,000 cycles as opposed the the "weak" 10,000 cycle std extractor spring.
Link Posted: 5/17/2004 8:07:40 AM EDT
I use my LMT Enhanced bolt with a standard Colt carrier for about six month now. I have not experienced any problem with the gun.

I also have a complete enhanced carrier assembly on my SPR and it has been flawless.

I am intereted in why some of your parts are failing.
Link Posted: 5/17/2004 12:00:56 PM EDT
Hmmm, I wonder if that third hole for gas isn't the problem? If you look at the DTIC conference on the AR15 and the powerpoint discussion of extractor lift, they point out that a certain amount of pressure is required in the chamber when the bolt starts to cycle as the extractor actually lifts off the cartridge rim and is held to the bolt face by chamber pressure until the extractor settles back down.

The LMT carrier takes more gas pressure to cycle it at the same speed as a Colt carrier. Nice if you have a lot of full-auto or you are using a can and pressures are above normal anyway. However, if your gun is tweaked to where it is just functioning fine with standard parts, you may be reducing the chamber pressure enough with the LMT carrier that there is no longer enough pressure to hold the brass to the case as the extractor lifts.

Here is the DTIC Powerpoint presentation on the subject, definitely a must-read if you plan on using "enhanced performance" parts in the AR15, as it is very easy to enhance your performance right into stoppage-land by emphasizing only part of the whole process:


Link Posted: 5/17/2004 12:24:10 PM EDT
I have a LMT Enhanced Bolt in a Standard LMT carrier.I just shot another 300 rds. today which puts me at nearly 1k with this set up in a LMT 16" upper.

Flawless so far.No malfuntions or anything irregular so far.

I shot some mags today that have been loaded for over a year (Chrome Silicone Springs) and they performed as intended also.I am very satisfied with LMT gear including my BUIS.

Link Posted: 5/17/2004 1:29:07 PM EDT
you guys are the best!
green 0 , you are right! i do have a backup weapon. it was just surprising to me that, it failed after just a couple of thousand rounds. after reading the threads about how reliable the lmt b.c.g. was compared to the standard usgi bolt. that was the selling point for me and why i was willing to pay the extra cost for such a fine piece of instrument of destruction. and far as the springs lasting 100K cycles it was more like 1.4k to 1.5k cycles. thanks for the correct phone number people. Grant always goes out of his way to help and i do appreciate it Grant. i had talked with lmt today but unfortunately chip was out of the office. i'm supposed to be hearing from them sometime tommorow, i'll let ya'll know the outcome. i have full confidence that lmt will correct this problem.

Link Posted: 5/26/2004 12:51:29 PM EDT

spoke with chip witt at the q.c. dept. nice guy, he gave me an rga# to send back the bolt.
he had received it and was sending me a replacement bolt. he is going to run some tests on the failed bolt. i asked him if and when he finds the problem, if he could let me know the results of the test. will have to see if he notifies me on the results. i did tell him that the approx. 2k rounds i had shot was in between a time of a month. i was giving my m4gery just a good workout,. anything i wouldnt do with my old b.c.g. hopefully the new bolt from LMT works just fine as they are advertised! because i really do like LMT b.c.g.'s engineering and craftsmanship. still bummed out though, it was alot of coin to pay for a b.c.g. and have it fail so fast... i'll see what happens with the new one

Link Posted: 5/26/2004 2:49:51 PM EDT
Have nearly 4,200 rounds through one LMT BCG and no failures as of yet. Any part can have trouble........including standard COLT
Link Posted: 5/26/2004 3:24:18 PM EDT

Originally Posted By Horik:
Have nearly 4,200 rounds through one LMT BCG and no failures as of yet. Any part can have trouble........including standard COLT

Not narly as much but very close to that number of round count. no problem on my end.

I just finished a test at a shoot. dumped close to 300 rounds in a full auto run with a dealer sample lower and not a single FTE problem with my enhanced bolt.
Link Posted: 5/27/2004 9:17:51 AM EDT
hey guys,
i'm happy to hear that the rest has not seen any failures to date. that makes me feel somewhat comfortable that my lmt b.c.g. was just a defective unit that passed q.c.
real test will be when i receive the new bolt and i'll run the same drill and see what happens.
just makes me leary now about any part that is "enhanced".i guess i'll have to do a little more research next time instead of just purchasing products becaused they are marketed to be "enhanced or improved" i will stick with usgi parts from now on when available

Link Posted: 6/2/2004 3:27:15 PM EDT
[Last Edit: 6/2/2004 3:30:00 PM EDT by meateater]
still waiting for my bolt and why the bolt f.t.e. hopefully i'll get both soon


Link Posted: 9/13/2004 1:56:36 PM EDT
well f*8K me , my p.o.s. lmt enhanced bolt springs are taking set again.
same intense drill as before. rapid firing and slow. failure around 1.3k now.
starting to notice springs getting soft again.
i wish i could remeber who i purchased it thru.. oh well live and learn. it will now be a paper wait to remind me that , improved or enhanced is always not the better option. just .02.
i will be ordering another usgi bolt as a replacement for the lmt.

Link Posted: 9/14/2004 10:49:51 AM EDT
[Last Edit: 9/14/2004 10:50:31 AM EDT by AShooter]
I may have missed something here, but what kind of buffer are you using?

I bought an LMT M4 upper with the enhanced BCG and the damned thing didn't work worth a crap until I got rid of the super-heavy DPMS carbine buffer and replaced it with a standard "H" buffer. I was ending up with the spent casing hanging halfway in the chamber and a live round jammed up tight underneath it. Looked like a failure to extract.

Runs great now, though! But I must admit that I have only put about 500-600 rds through it.


Link Posted: 9/14/2004 12:38:36 PM EDT
vltor stock, and usgi buffer.
it,s the extractor springs. when you can litterally push on the springs and the pin is about to fall out.
anyway i dont want to keep beating a dead horse. i've got my usgi bolt on my m4gery and it will stay with usgi from now on.

Link Posted: 9/14/2004 6:22:10 PM EDT
I played with a used LMT enhanced bolt but won't work with their own CQBR. Fail to extract.
Link Posted: 9/15/2004 11:11:17 AM EDT
I had similar issues, for anyone researching the enhanced bolt.

Top Top