Hi All, I looked, but so many different answers I figured I'd post.....

Took my new LMT build to the range today (upper is 15.4 LMT from JTAC/ lower is complete LMT Defender 200 from Legal Transfers with SOPMOD)  The rifle shhots great, but after the first 5 mags or so, it began to fail to feed the first rounfd in the mags. It worked fine prior to that and the mags have been 100% in my other rifles. I used the forward assist to seat the round and all subsequent rounds fed with no problems. This was the first time firing this weapon.  The reounds seemed to 'hang' between the feed lips and the feedramps. This even occured when I downloaded by a round..the first round ftf and worked great afterwards.  As I said, the firat five mags worked great then the problem started on all mags except the enhanced mag from DSG with the magpul follower and chrome silicon spring. All the other mags are D&H and have been flawless until now.   Any ideas to fixe this?  The gun shoots fantastically well, but I've GOT to get this running 100%!!!! I hope to use it as my SHTF weapon.

BTW:  total rounds fired = 300

ETA: A couple of hours after coming home from the range (prior to cleaning) I tried to recreate the problem and every mag loaded the first round fine...WTF???

Thanks!

Some times it kind of a break in peroid. things smoothing out, and starting to work together.

clean it, and look for any strange wear, or burs on the feed ramps. lube and shoot it.






Invisiblesoul

does the bolt stay open after last round?
can you lock the bolt back without a mag in it?
What brand is the BC?

I was having the same problem on a WOA upper.  I changed the bc and it ran fine.  I also changed out the buttstock at the same time because I wanted to go in a different direction.  So I guess I am not sure what "fixed" the problem.  But, it was exactly the same problem you are describing including the inability to "recreate the problem" since it only happened after the rifle heated up.  Tweak and some others here thought I had a protruding buttstock screw that was screwing-up the travel of the buffer.  Another guy thought it was the WOA BC.  If you can search into the archives you should be able to find that post, it was tacked for a while.

Good luck.

Quoted: does the bolt stay open after last round? can you lock the bolt back without a mag in it? What brand is the BC? I was having the same problem on a WOA upper.  I changed the bc and it ran fine.  I also changed out the buttstock at the same time because I wanted to go in a different direction.  So I guess I am not sure what "fixed" the problem.  But, it was exactly the same problem you are describing including the inability to "recreate the problem" since it only happened after the rifle heated up.  Tweak and some others here thought I had a protruding buttstock screw that was screwing-up the travel of the buffer.  Another guy thought it was the WOA BC.  If you can search into the archives you should be able to find that post, it was tacked for a while. Good luck.

That's kind of what I was thinking, since it indeed only happened when 'hot'..thanks for the tip.  I hope that's not it as I have the standard LMT BCG....I'd like to keep it 'together' if you will if possible, but whatever it takes to get it running 100% is the only important thing.  I have a couple of BCGs and may try one next range trip.

Quoted: Problem with swapping B/C's is you may have one that is already broken in and the rifle may run with it, but until you break in the B/C that you bought to install in this rifle (allow the key and cam to mate to the upper track) your really have not mated all the parts. Simply, keep the upper bearing surfaces well lubed with CLP, and the parts will mate threw live fire. If needed, re-lube the bearing parts every 100 rounds up to the few hundred mark if needed.  This will allow the parkerizing, anodizing, and gunpowder accumulated fouling to be flushed from the system, and replenish the CLP that may be gummed or burn out of the system.

Thanks for the advice, Dano523. I'll continued to use the rifle as is to give the parts time to mate well and see how it works out before replacing anything.   I appreciate everyone's input