2ndAmendMedic

It doesn’t slam fire, that’d be fun, but quite scary... What I meant is a good bump will make it disengage off the bolt catch. The bolt wouldn’t catch previously, now it does. The upper receiver made contact with part of the bolt catch and kept it from engaging properly, now it engages, but barely. The slipperiness may be due to the NiB coating on the bolt? I noticed that the upper receiver was making contact with the bolt catch and would not allow the bolt catch to properly engage and it would not hold the bolt open on last round or even when manually locking it to the rear. I cut down the area of the bolt catch that was making contact with the UR. Area in blue triangle in the pic was cut. It seems to work okay for now. It could be that I got the wrong spec bolt catch? I used a CMMG .308AR LPK so it should’ve been GtG. I haven’t had much range time recently to mess with it further as I just had another kid. Family takes precedence.

I’m no gunsmith nor am I pretending to be one. But this seemed to remedy the situation for me. My bolt catch works better now, but it’s on a “hair trigger.” As in, if I give it a smack anywhere on the rifle the bolt rides forward. It locks to the rear on empty mag and it cycles fine. specs are Gibbz G10 upper, Shillen match barrel and bolt, NiB BCG. 80% Arms lower, CMMG lpk, Geissele SSA-E trigger. The rifle shoots about as good as I can; I’m still quite a novice at LRS. I’m working a few other things out on the rifle, but I’ve enjoyed it so far. I hope this helps or maybe I’m wrong?

I’ll see what I can do. I should be able to snap some pictures tomorrow.

I had a similar issue with Gibbz G10 upper receiver. The upper was disengaging the bolt catch. A bit of modifying the bolt catch and it cleared it up. It was the cheapest part so I figured why not start there. It seems that their uppers are out of spec. or aren’t designed to work well with non-Gibbz lowers. It’s a shame, I really like a side charging semi-auto upper in .308. Makes me hesitant to purchase their MG4 for an upcoming project I had in mind.