Brand New LMT Defender 2000 Sopmod complete rifle. Cleaned and well lubed before heading to the range. Every 4 or 5 rounds I would have a failure to feed . The round would get hung up on the feed ramps (see picture) It also happened once or twice putting a fresh magazine in and dropping the bolt catch.
I was using Federal Lake City XM193 same lot I have used in a colt 6920 and a Robinson XRC with no issues. Tried 3 Pmags 2 Newer style ones where the cap snaps on the bottom and an older one and also a USGI magazine. The FTF happened with all magazines.
Anybody have suggestionsof what to try next ? I plan on calling LMT tomorrow. The gun shop I purchased the rifle at suggested dropping it off and he would polish the feed ramps before contacting LMT . Do you guys think that would help?
One more problem I had with the gun was after installing a Magpul BAD lever and playing around with it ( rifle was still un fired) the bolt catch plunger hung up. I had to punch out the roll pin and work the plunger to get it to pop out. Put everything back and that seems to be working fine now.
I am little frustrated at this point because it is brand new but I am sure LMT will sort it out.
I would not polish feed ramps. Check buffer spring length min length is 10 1/16’'.
Also from the photo it is hard to tell but I would add more lube. My LMT needed 500 rounds of XM193 before the BCG was broken in mine was pretty stiff and I used lots of lube think dripping wet inside and out. Also I would check the gas tube alignment into the gas key just to make sure.
Linky to quibs gas tube alignment post. http://www.weaponevolution.com/forum/showthread.php?t=1613
I would also hold off on installing the bad until you get the rifle broken in it is not causing your failure to feed but it has been known to cause some problems with the bolt not locking back on the last round. When you get some rounds through it with out a problem then I would install it .
Hmm. As an LMT owner, I’m pretty curious about what the cause of this could be. I’ve never had any issues with my LMT and never seen a repetitive malfunction like that before on any M4. I’m sure that the M4 gurus here will chime in with some wisdom and shed some light on this though.
Strange, but it looks in those pictures like the bullet tip has cleared the feedramps and the neck(shoulder, whichever the proper term is) of the cartridge is stopping at the ramps. Considering how much ass the bolt should be moving forward with at this point in the cycle, I have trouble imagining what could be jamming things up.
How many rounds did you fire? Just SWAGing, but does it look like there’s any unusual wear on the bolt face or extractor?, Anything that would prevent the rear of the cartridge from riding up and into place?
Really interested in hearing some educated replies from the gun gods on this one.
I agree it looks like the bullet has cleared the feed ramp.
I got 2 FTF like that when i got to about 1800 rounds but i was shooting weak ass UMC out of a hot and dirty gun. When I got home and cleaned it I measured my buffer spring it came in at 10 1/8’’ I replaced it and I haven’t had a FTF again so far that was 400 rounds ago.
I thought I gave it a good coating but that area was a little dry when I just checked. The rest of the bolt carrier was well coated I have been using weapons shield.
I checked the gas tube alignment the bolt does have some resistance when it hits the gas tube. I can see the tube move to the right (when looking in the receiver from above) when the key makes contact. Is that little resistance enough to cause the failures? I forgot to mention I only ran 60 rounds through it today and the rounds that where jammed had dents in the casings after I extracted them.
Mine has a slight resistance but I have NO movement of the gas tube and when I do the sharpie check none of it has been rubbed off.
May be Quib can enlighten us if this is causing a problem.
The lube for me my BCG was stiff to collapse until i had 500 rounds through it. If I road the CH my BCG wouldn’t lock up unless i used the FA. I used lots of lube for the first 500 after that it loosened up nicely.
Check the bolt for any burrs or bad parts…specifically the extractor and bolt face. Check the lip. For whatever reason the case head is not seating into the bolt head. The extractor will hop over the rim of the case. That is not happening here as you can see the case rim is trying to go into the bolt but something is stopping it. Check the ejector. Sometimes there can be a burr in the hole the ejector sits in, and the ejector will not move freely. Just push it in with something, and see if there is unnatural resistence such as a burr.
If you have a spare bolt try that or even a spare extractor. If the one you have now has a black rubber o-ring take it out and test it if possible.
The bolt does not appear to be any burrs on the bolt. I do not have a extra bolt but I do have a spare extractor. The ejector moves freely.
My extractor has the o-ring short spring and is fairly hard to move. The spare I have has a longer spring and the blue core and moves much easier when installed.
I can put my spare in and give it a shot at the range tomorrow
10 1/4’’ Is in spec butt a little on the short side IMO. I think with the buffer spring being short and from the pic it looks like you could use more oil on the BCG.Both are contributing to your problem. IMHO YMMV
The way I oil mine for a new rifle breaking in. I do 2 drops down the gas key , oil the rings until the oil is dripping off the rings , fairly heavy coat in the bore were the gas rings cycle in and has much oil has i can get on the cam pin,cam pin track on the carrier. The first 2 or 3 shots it will spray oil out of the 2 exhaust holes on the carrier.
It is not the extractor. I replaced it locked the bolt back and loaded up a snap cap and released and was still experiencing failure to feeds. I put the old extractor back
in and it was doing the same. Check out what it did to the snap cap!!! I think I got a bad LMT
I am not sure why the bolt looks discolored in the photo it did not look that way to the naked eye
Looks like a couple things are happening, from the pics. First, the chamber mouth may have a bit of a hard sharp edge, causing the gouging on the middle of the cases, and slowing the chambering process. Second, and probably more importantly, it appears that the the case rim is getting hung up on the bottom edge of the extractor. When assembled, is the extractor leading edge further forward than the bolt face? If so, this could be causing the hitch, too.
Maybe the bolt is machined in a fashion that puts the extractor too far forward. Swap a different bolt in, and leave everything else the same, to see if that solves the issue.
I would suspect those gouges are from the 6 o’clock area of the chamber mouth, as the round gets rammed into the chamber, at an angle, because the case rim is not sliding up into the bolt face, because it is getting hung up on the extractor’s bottom edge. The reason there are two gouges, is probably because he tested this snap cap two times, with the same jam occurring. The bolt is not contacting the side of the cases.
I would bet a different bolt solves the issue 100%. Just if you had a buddy’s to try tonight…I’m curious!
I don’t have a solution for you but I would suggest you call LMT this week. Possibly even send them the pics. Do you have another rifle to swap out the bolt with? Or try the bolt in another rifle? LMT test fires 30 rounds through every upper so it is rare to have a problem like that. Hope you get it figured out, I have a few LMT’s in my safe and never had problems knock on wood!
