This is a follow-up post on the previous issue with my FM9 LRBHO problem. The plastic cam was rising above the edge where it meets up with the upper so it was getting pinched down, and not allowing the lifter to fully lift to engage the LRBHO. I sent pics and videos (including blowback9’s videos on this exact issue) to FM and they just requested i send it in. So i did, since i wasn’t keen on potentially ruining a part with imperfect dremeling. They said the cam was not the issue, but rather the buffer system. They ran 5 mags, all of which apparently locked back, then the bolt catch bent and wouldn’t lock back anymore. I reiterated the pics showing the cam rising too high and they just said yeah if the LRBHO is properly installed, it’s not an issue. So they replaced the now-bent bolt catch and sent it back. When i got it back, i went ahead and dremeled down the cam myself, and it now sits perfectly. Took it to the range yesterday and the first 5 mags ran perfectly and locked back. THEN it jammed up mid-way through a mag, and following that i was unable to drop the bolt on either side (lever or button) without knocking it down a bit with an empty mag. So the last two mags ran through, but didn’t lock back. I figured the mech just got dry and i didn’t bring oil with me. When i got it home and inspected it fully, i found the bolt catch was slightly bent and would not seat all the way down, flush into the groove. FM sent me some extra bolt catches before this range session which i plan to replace, but wondering if this is going to continue to happen, and if there’s a particularly strong bolt catch i could get, but it seems FM’s catches are proprietary. I plan to get a measurement of distance between bolt face and bolt catch and maybe order spacers depending on that distance. Also, there seems to be a 1 or 2 mm gap in the bolt catch groove, which i’ve read can be shimmed somehow? I’m not in metallurgy and i don’t quite understand how you can shim a moving part. I might trim the bolt catch detent spring as bb9 has suggested. 

\-Stock: Maxim CQB with RDB buffer  
\-Trigger: Rise Armament Rave PCC trigger  
\-124 gr Freedom Munitions FMJ  
\-Stock FM bolt with amazon spring  
\-FM Mike9 7 inch trilug upper  
\-FM Mike9 ambi lower  
\-Glock OEM 32 round mags (planning to switch out to some wolff XP springs)

I have a milkman on the way too and unsure if that’ll make the issue worse or better. 

\*\*Note that the images show the LRBHO cam problem, which has since been corrected, and now sits flush with the lower, when actuated. 

FM9 bent bolt catch