ehall

sold

This is a 13.5" ION Ultra-Light handguard from SLR Rifleworks for a high-profile LR-308 receiver. The lightweight rail cut and short overall length makes it perfect for a 16" 308 w/ a high-profile receiver. Product link is https://slrrifleworks.com/308h-ion-13-5-ultra-lite-handguard-mlok/ This one is very lightly used, no major scratches or defects, only selling because I replaced with a longer version for more gizmos. I am including the unused barrel nut and wrench from the replacement kit. Located in St. Mary's County, MD. $100 paypal

Has *anybody* been able to make this stuff cycle? Who's got a trash barrel we can drill to .125, and a suppressor?

https://www.sellier-bellot.cz/en-us/products/rifle-ammunition/rifle-ammunition-fmj/detail/769/

I bought a couple of hundred rounds of it a while back on a steep discount sale, still have +180 in the box. It loads in LR/SR PMAGs and Lancers no problem and works with manual cycling of the action. I haven't studied it very much, not even any kind of sight-in testing, just shot enough to see if it will run through the gun. It's NATO ball ammo, so not going to do much except pass straight through, probably no fragmentation or expansion. 300 is going to be better for a lot of reasons, and there's only one scenario where this might be better which is being able to snipe with your existing 308.

Yes I read it, lots of good info.

hopefully long enough for the carbon to catch up

I sealed the gas block to the barrel with some loctite 620 and some blue around the roll pin and adjuster screw, and it seems to have resolved the issue--LRBHO working on several different types of ammo, across several different 2-round mags (before it would only run the first few then stop locking open). The gas port on this Criterion barrel is definitely small, but it can be made to work with a lighter buffer, and the smaller size lets it cycle smoother, so being small isn't entirely bad. However there are other arguments in favor of drilling it larger (subsonic ammo, for example), and I am going to do that, but I will make another thread for that discussion. To answer the original query: Forward Controls 7.62 ABC/R is the preferred bolt catch--its got the best machining and finish, and the fact that it will not catch the BCG body means that its a simple pass/fail observation for testing (it either locks open on the bolt, or it closes all the way). Thanks for the comments.

I'll open it a little but I'm not looking to get into H3 sizes. I have the AGB to deal with it but I'd prefer to stay in the middle of the range instead of swinging between the extremes, if possible. One thing from that other thread: "most 308 ARs are pretty overgassed because people expect them to run military ball which is significantly underpowered compared to good commercial 308." I'm seeing the problems with 7.62x51 spec NATO ammo and some .308. The steel case stuff and some of the other ammo has had fewer issues. No issues cycling any of it like some people were complaining about it in the other thread, and I am larger than most of those. I'd like to get to the edge where NATO works reliably with H2 and stop. I'll try to figure that out and post another followup after.

https://www.snipershide.com/shooting/threads/possible-undersized-gas-port-in-criterion-barrel.7016262/

Just measured it at .079. Its an 18" with the rifle-length gas. That would put it on the small side. https://criterionbarrels.com/products/large-frame-ar/dpms-pattern-308-hybrid-barrel-rifle-gas-chrome/?v=7516fd43adaa I am also checking the throat of the gas key and a couple of other things while its apart.

I replaced the SCS and still the same failure. I also have the same Titanium block on another 5.56 AR and it doesn't have any problems there. I use that gun more, with a larger variety of ammo, so I expect it is carbon sealed, whereas this gun does not get used much and the ammo is generally better.

Well, I was doing it for testing, since some people were blaming the JP SCS. If I don't care about LRBHO (which I do) then I can keep the adj block about halfway with the JP H2 and it cycles fine, it just doesn't lock open at the end. It is possible that the gas port is undersized. I have a set of rod gauges to measure, and I'm going to ask Criterion what it is supposed to be, we'll see where that convo goes. In the meantime I'm going to seal the block and around the threads of the adjuster screw, see how that goes. If it still fails with no leaks around the block then it is very likely to be the gas port. Other possibilities are with the Lantac BCG (no evidence of leaking anywhere) or with the buffer extension. Or who knows what. Also to keep this kind of on-topic, the FCD ABC/R is what I am currently using because it has the smoothest finish whereas the cast pieces are thicker with rough surfaces.

Wanted to post a follow-up: I reduced the weight of the JP SS from H2 to H1 and it ran perfectly for a few 2-round mags, then stopped working again. I swapped in an Aero rifle-length spring and buffer that had been reliable in the early build, and had the same thing happen. It seems that LRBHO works fine for a couple of mags until things heat up, and then it stops working, reglardless of bolt catch, magazine, or buffer. I did a full inspection on the gas system--full disassembly of the SLR block, verified alignment, pipe cleaner down the tube, everything. No real issues that I could find so I oiled the parts and put it back together. Another test and the same thing happened again, but now I see that the block is leaking pretty badly. Current working theory is that the block holds tight when the gun is cold but expands more than the barrel once it starts getting warm. A little googling indicates that other people have the same problem with the SLR and LRBHO. I have a couple of other blocks here that I can throw on to test but the Lantac Dragon is secured with Rockset and I am looking at other options first. If it is heat-related expansion then I will probably have to get a steel block to resolve.

I bought a couple more Magpul LR/SR mags and some more ammo, and went back to the range to test for a bit. The BAD catch doesnt hold the bolt back with any of the 7.62x51 NATO rounds. Some of my .308 match ammo holds back partway on the Lancers (catches the BCG body not the bolt face), but doesn't hold at all on the Magpul. The Tulammo steel .308 holds everything back even with the gas block closed off a little (guess its the opposite of the .223 steel). I put on a suppressor can with no baffles, enough to create a little extra pressure, everything holds open all the time. At this point my theory is that the gun is undergassed, so I'm ordering a couple of steel weights to get some more movement from the JP SCS (relying on the adj gas block for precision). Will report back again after. ps--the BAD is weird looking but its the easiest to manipulate so far

The AR-15 style only covers half the ramp, while the large-frame style covers the full ramp. Look at the ramped part of these (from above), the upper two are missing the right half of the ramp: I can tell from your pictures that yours is using the AR-15 style ramp. If its working for you then I will look at it. I'm a little worried about material thickness, plate width, etc., the large-frame BCGs are much larger with much more mass The ArmaLite part that I bought was their larger mag release. Nothing wrong with it, just didn't seem to be a very thoughtful design.

I bought one of the BAD 308 Enhanced Bolt Catches, the one they market as Investment Cast. Its similar in dimensions to the FCD but has a slightly taller wall surface. This one is able to catch the Lantac bolt body if I wiggle everything right. It looks like a Strike part with the stylization but it has a good feel to it. I also got the ammo that I ordered, so I will report back after testing, after it stops raining.

The only Badger bolt catch that I can find has the AR-15 style ramp. I have been looking at the Armalite catch but frankly I was not impressed with the last part that I bought from them.

BAD 308 Enhanced Bolt Catch - Investment Cast pinholeto butt nose to back wall thickness wall height

I had a little time after yardwork today so I ran to the range real quick. Only tested a little bit. The Lancer 20-round mags hold open with the FCD and the gas port almost all the way open, but the 10-round mags do not catch the FCD even with the gas port all the way open. I only had some 7.62 M80 and I forgot to grab the Magpul mag. Need to order some more steelcase and M80 and another Magpul mag, and do some more testing. Looking at getting another bolt catch / release sometime too.

Interesting observation already just from cycling manually: the FCD will not catch the Lantac BCG body, only the lugs. Evidence that the problem is that the Aero catch is too tall.

I uploaded the wrong image above and failed to make the edit window. This is the correct measurement for pinhole to butt on the FCD ABC/R, not the 0.66 shown

Forward Controls Design 7.62 Augmented Bolt Catch / Release (ABC/R). I believe this is the v3 because of the extra lip on the thumb pad. pinhole to butt nose to back wall thickness wall height

Aero .308 bolt catch / release pinhole to butt nose to back wall thickness wall height

Aero on the left, Forward Controls on the right. AR15 on the top, 308 on the bottom (I have been using the Aero 308). The only thing that jumps at me is that the FCD 308 has a thinner leading edge and a smoother surface--its possible that the taller rougher surface of the Aero is putting more drag on the BCG, causing it to lose some momentum. I'll post measurements in the spec thread and report back after the next range trip.