A little frustration & thanks

I’m a former Marine 03 and a lurker here. After a stunningly bad mishap, my right arm was disabled for almost a year. My good friends at CavArms sent me a CavArms/Sabre polymer lower to help me get well and I threw a 16" Sabre middy (M4 feedramps, Sabre internals) on it.

Had a lot of problems with the round not feeding all of the way and getting stuck. The bolt would go forward about 3/4 of the way and then I had to usually pry the bolt back to eject a round that was badly dented from the feedramps. This happened with el cheap PVI and Remington range ammo (green and white box, 5.56mm). New PMAGs and used USGI mags both did not alleviate the problem.

PMed my friend GotM4 and he suggested I bring the weapon by so that he could check it out. He ran Ned Christiansen’s chamber reamer through it and “removed a lot of metal.” He then upgraded the extractor with a Crane O-ring and also properly staked the BCG (he said it needed a bit of touching up).

Flash forward to last night. The rifle was wet with FP10 (as usual). With the Remington ammo, I had a few instances of the bolt not going all of the way forward and whacking the forward assist didn’t work as well as pulling the charging handle about halfway back and letting it go. The PVI stuff was very frustrating at first, exhibiting the malfunction I mentioned 2 paragraphs above. After a few of those jams, the weapon settled down and I ran 2 mags through it with no problem at a fairly high rate of fire. Then the range closed and I came home to do a thorough cleaning.

Am I out of the woods yet? Am I just tightwad that buys crap ammo?

Many thanks to GotM4 and CavArms. Class acts all the way. Also, Chad of PFI Optics graciously loaned me a Trijicon Accupoint that I fell in love with. Gratuitous gun porn below with my German head of security.

If it’s failing to close the bolt on a live round try removing the o-ring.

Sounds like it’s doing a lot better. If removing the o-ring doesn’t work I’ll give you a box of XM193 to try.

I bought the BCM upgrade kit on a whim but I’ll try removing the O-ring for now. Hitting the chamber with a bore mop that fits it and a strong solvent in case of laquer build up.

Thought I’d update this thread with the solution:

-switching to a DPMS chromed bolt for ease of cleaning fixed the problem
completely so far.

sounds like ya might have gotten it. out of spec bolt perhaps?

nice to see another Cav Arms guy on here. i love mine.

i live in a ban state so the nice solid light fixed stock setup is perfect for me. :cool:

LL, glad your AR is humming along nicely now.

I want to try out a chromed BCG myself…maybe Young’s MFG…I haven’t decided yet.

Very odd since chrome bolts aren’t ‘mil-spec’…

I haven’t fired your rifle but of troubled ones I have fired I have yet to see one that I couldn’t get to run. I’d like to see your first hand and see if I can get it to run on a non chrome bolt.