Harveyshot

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As stated earlier, I bought the Armalite 10A bolt catch and it has worked great but I've only used Hexmags with it. No steel ammo, range won't allow it.

I just must have been lucky on my one and only LR-308 build. It's an 80% polymer lower and I bought parts from a bunch of different sellers and except for the bolt catch all eventually worked out in the end with no drilling or modifications to any of the parts, just some tweaking. The buffer assembly I bought (Luth-AR LR-308/AR-15 MBA-2 Skullaton Stock Assembly A2 Tube .308 Rifle Buffer And Spring Dark Earth MBA-2FK308 | Cheaper Than Dirt) didn't specify the buffer weight only that it was 'standard' but it worked. I did buy an adjustable gas block made by Sadlak Ind. and that, I think, made all the difference. Once I opened it up, all the FTLs and FTEs went away. The Armalite AR10A bolt catch replaced the one in the LPK. It has a 20" barrel from CDC and rifle length gas. I would have been up poop creek if mine had required drilling. Yes, the red dot optic color doesn't match the rifle but that's what happens when you order from the picture without reading the description. It 'looked' FDE. (sigh) Hope your 308 works out well, James.

The third one I bought was the one that finally worked the way it should, the AR10A bolt catch from DSG Arms.

Final Update Installed the Armalite AR-10A bolt catch, lubed everything excessively and went to the range. The first 20 or so rounds loaded and ejected without fail but the bolt wouldn't hold open after the last round. It was a choice of bc (3rd one) still not catching or not enough pressure to push the bcg back far enough to be caught. I opened the gas block a little more and lo and behold, it locked open! After that the rifle performed flawlessly (me, not so much). Happy camper. A big thanks to all that helped.

I built an 80% (aluminum) AR-15 six years ago and enjoyed the research, milling and drilling of something I'd never done before. Now that I'm retired and looking for things to do, I decided on an 80% (polymer) LR-308 for the same reasons. I've finished (after much anguish of waiting for parts in the mail, ordering wrong parts, etc.) and it's on to the next project. Thinking 80% AR-15 lower and dedicated .22 upper.

Received the two adjustment screws from Sadlak with no bill. I'll be sending them $25 and hope that covers it.

Update on the bolt catch problem. Finally got the Armalite AR-10A bolt catch from DSG Arms. First of all, the pin hole in the Armalite bc is slightly smaller than the holes in the other two bcs I have. Therefore the bottom edge of the Armalite hole is slightly higher than the lower’s pin hole bottom edge. I could not get the screw/pin to go through the bcs hole. So, out of non-destructive ideas, I got the Dremel out and ever so slightly lowered the groove in the lower just below where the plunger sits. It worked! The Armalite bc moves and sits better than the previous bcs. It also catches a tad more of the mag’s follower. Range time will be the test but that will have to wait for now. And kudos to Sadlak Industries. I lost the adjustment screw to their gas block and emailed them about a replacement. They immediately replied telling me not to fire the rifle with that screw missing and that they would send me one. According to them, it’s a hard to come by stainless steel set screw. I told them I would pay them if they would send me two. I probably should get a spare gas block for instances like waiting on the mail.

Never tried a .45 but if you’re working on a .308 bolt you likely have a .308 case lying around somewhere.

Sounds like a great way to check the sights. I’ve taken a 3-8x scope from another rifle and put it on the 308. I’ll try that method before going to the range. From my minimal experience, a non-magnified red dot is pretty much useless at 100 yards unless your target is big.

Thanks for that link, jtalien83, but it just added to my confusion. I’m starting to think I’ll have to buy one of every make and model and try them all. That little nub on my current bc, that the follower pushes up, barely makes contact with the follower. I think the 10a might be a viable choice because it ‘looks’ like that nub is wider and more towards the end of the bc but they are hard to find.

Question: 10A or 10B? Looking at the differences between them from a page on this site, it looks like the 10A would work better. But what do I know.

Aero Precision. Never actually tried out their bc on a functioning rifle, just didn’t like the way it moved so little and sat cocked in the lower. Does everyone’s bc sit that way? Ordered a Luth-AR bc and it did the same. Although, when trying the bc out a few weeks ago (just manually operating the bcg), it worked. All the parts we’re pretty much dry. I’ll try the Armalite one and hope for the best. Thanks.

Funny thing, I did lose the gas block set screw. I’ll check with Sadlak about the size.

Back from the range with an update. After about 50 rounds, she almost did perfectly as far as feed and eject go. Near the end there were a couple of ftf and fte. Broke it open and oiled it some more. Didn’t help. Then I remembered DNP saying start it with the gas block wide open so I opened it quite a bit (didn’t want to lose that screw at the range) and that seemed to work. So thanks everyone for all the advice. The remaining problem now is the bolt catch that isn’t catching with an empty mag inserted. I would put two rounds in a mag and fire off both but no catch. Did this many times. At first it would catch if I used the charging handle but at the end it wouldn’t. When I look at it with the gun open it just doesn’t seem right. If you can see it in the pic, the catch is barely making contact with the follower when the mag is fully inserted. The one pic shows it with the mag almost fully in. There are other pix of the catch in the original post. I’d appreciate anyone showing their bolt catch. Thanks.