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Posted: 6/1/2015 3:48:57 PM EDT
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Finally stopped raining long enough for things to dry out enough to make it to the range with my new 9mm AR. My first one and first time shooting one so total virgin experience.
Lead up to the actual putting rounds down range - Build Thread Barrel Issues (Short answer the adco barrel didn't work for me for this build with feeding issues and ammo deformation, switched to QC10 barrel) Parts List Synopsis from build thread (some junk bin parts, some purchased parts) - QuarterCircle 10 - Glock Small Frame Lower PSA Slick Side Upper PSA basic LPK w/o FCG ALG FCG QuarterCircle 10 - 5.5" barrel Seekins MCSR v2 9" Odin Works Pistol Buffer Magpul K2 grip Glock OEM 33rd mags Magpul Front/Back BUIS SIG Brace - Magpul MSR sling JP SCS 9mm JP 9mm Bolt Primary Arms MDS RDS (trivia note, I had to dial the RDS waaaay down, OOTB on this rifle it was shooting 18" high at 25 yards but only 1" left) Currently has a Octane 45(+9) HD on it for suppression, will have a dedicated F1 7" in titanium when I get my parts. Feeding - I'm happy to report that out of 500-600 rounds, mostly double and triple taps as the kids say, I had a single failure to feed and that was from riding the bolt home on a new mag. This is a big no-no on a QC10 Glock lower gen 2 which has no feed ramp. Also this is after switching from the ADco profiled barrel to the QC10 profiled barrel (barrel issue thread above has all the details). Ammo / Function Testing - Ammo used including - Commercial ammo : 115gr WWB FMJ, 115gr Blazer FMJ, 124gr Federal Hydra-Sock, 124gr Federal HST +P, 147gr Federal Hydra-Shok, Reloaded ammo 115gr Hornady XTP (jhp), 115gr Ranier Plated RN, 124gr Ranier Plated RN, 124gr Ranier Plated HP, 124gr Berry's Plated FP, 147gr Ranier Plated RN, 147gr Ranier Plated HP Special ammo - I have some low speed subs in 147, around 900fps out of a lonewolf threaded barrel in a G17/G22x9 that I shoot sometimes when I want to show lookie lous "this is as quiet as you can get and still have a 100% functioning gun" All the reloaded ammo was sitting over somewhere between 3.3 and 4.8grs of TiteGroup depending on weight. I didn't chronograph anything, some knucklehead managed to put a round through it last trip. It was obvious to the ear though which were subs and which were supers. The 115 and 124 commercial were all supers. The 124gr RHP's in reloads were subs, it's my standard range ammo. All the 147's were subsonic. All fed, cycled and ejected just fine even the low pressure stuff. I didn't shoot it unsuppressed but all ejections were between 2:30 and 3:30 and landing 5-8 feet away from a standing position which put the ejection port about 5'-6" off the ground. Recoil Impressions - Subs were lighter than the 556 AR i brought for comparison, supers were a hair lighter. Accuracy - Excellent, from a 'rest' at 25 yards (max range today), 10 rounds was a bug hole albeit a large cicada with WWB. By rest I just held it against one of the canopy posts to steady it and shot it from a standing position with the 2MOA dot dialed down until I could just see it. No complaints at all. Feeding Flawless with everything I put through it, again barring the single my fault failure to feed. Ejecting Flawless with everything Gas Face - Note that this build does not have a gas/ejection plate on it. I'm not too stuck up on looks but those things look awful on a gun. Gas in the face, there was none to speak of and right arm / shoulder ended up clean. The heavy bolt / buffer combination and a splash of RTV on the CH slot made for a pretty enjoyable experience gas wise. Bolt Hold Open - Horrible. Out of trying many many magazines, I took an 50 cal can full of magazines and tried each with only a few rounds in them, g19's, g17's, g18's, BHO was at best awful. 2 times out of 30+ emptying a magazine. And it wasn't repeatable with either magazine or ammo type. Manually cycling it holds open every time on every magazine I've tried which is a good number. So I'm going to be looking at any tweaks or changes I may need to do to get a somewhat more reliable BHO. There's about 1/8" bolt pull past lock up. i.e. if I pull the bolt all the way back with the charging handle and engage the bolt catch the bolt only goes forward about 1/8". Any suggestions on a fix are appreciated in advance. Final impressions - It's the most expensive build I have if you take glass out of the equation. So that's a down side. I could have built two 556 AR's for the same cost and that's not bargain basement AR's so it's not really cost effective short term other than the fun factor. Over the long run in sub 100 yard training it'll pay for itself and then some if that's a consideration for you. The recoil is close enough to a 556 to my highly calibrated shoulder that training sight aquisistion with it is viable. It's light and very maneuverable, quite more so than my 11.5 and 14.5 SBR's. All in all it's quite a bit of fun to shoot and with the low speed subs it's stupid quiet especially with that JP buffer system, no cheese grater. Note it's not 300BO quiet (10.5" with Specwar 762) but close enough for government work. |
| Are you sure your bolt is traveling far enough to allow lock back? Check by manually pushing in thr bolt stop and firing. If it locks you've got another issue (try clipping off a coil on the bho spring they send) also if it doesn't lock back you're not getting enough travel, try a lighter buffer or spring combo. |
| You may be getting bolt bounce (cycling too fast) and not allowing enough time for the BHO to engage. I still have a bunch of testing to go but recently I swapped to a 12oz buffer in my suppressed GSF build and my BHO started working reliably in the few times I tried. |
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Firstly thanks for the comments and thoughts.
Specifically - Manually cycling it travels back about the perfect amount as I understand it. There's roughly 1/8" between the bolt face and the bolt catch at full extension. I didn't know about the trick of checking the bolt catch manually while firing to check for that but I'm going to try that on the next outing. Quoted:
Are you sure your bolt is traveling far enough to allow lock back? Check by manually pushing in thr bolt stop and firing. If it locks you've got another issue (try clipping off a coil on the bho spring they send) also if it doesn't lock back you're not getting enough travel, try a lighter buffer or spring combo. Quoted:
Are you sure your bolt is traveling far enough to allow lock back? Check by manually pushing in thr bolt stop and firing. If it locks you've got another issue (try clipping off a coil on the bho spring they send) also if it doesn't lock back you're not getting enough travel, try a lighter buffer or spring combo. I quote JPE and surely they wouldn't lie about it... 
" In fact, when combined with our JPSCS-9MM, you have the heaviest, most reliable 9mm operating system that dramatically reduces bolt bounce while improving accuracy. " I know the SCS buffer is hella heavy to my uncalibrated mitts compared to any HX buffer I've handled. Quoted:
You may be getting bolt bounce (cycling too fast) and not allowing enough time for the BHO to engage. I still have a bunch of testing to go but recently I swapped to a 12oz buffer in my suppressed GSF build and my BHO started working reliably in the few times I tried. I did a lot of watching things last night with manually cycling and a 'slow' charge will cause it to not lock back quite a lot of the time. If I yank it back it locks back. With just a slow pull back it doesn't look like the BHO lever is popping up every time, like it's needs a little bit of encouragement. I tried putting a fractional bend in the catch arm which honestly I don't know if it made any difference or not. Manually cycling not, but I need to actually fire it to see if it made a difference at speed. The tolerances on the BHO seem fairly persnickity just watching the entire mechanism in slow motion both with and without the upper on it. With a redesigned bolt I could maybe see where it could be made more reliable but that would lock you into using a QC10 bolt on their lower and probably not something they want to do. QC10 does have a new bolt design due 'soon' FWIW. Still some things to check, see if the spring is too strong, see if it's bolt bounce, shave a gnats ass off the bumper to give it a little bit more bounce room (although that risks bolt catch breaking from what I understand if you take it too far). But... with that said, having it be glock compatible was higher on my list of wants than having a reliable BHO. I'd love to get both but I'll settle for using glock mags if I have to. Still going to be my 'go to' short range toy regardless. |
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