[ARCHIVED THREAD] - PA10 Nitrated 18", Gen 2 observations / fixes... Criterion barrel results 10 Sept '17. (Page 1 of 5)
Posted: 7/8/2017 9:45:42 AM EDT
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This thread is going to seem a little chopped up, I am posting at a few forums.... and In order to keep my sanity... I will cut and paste info as I post, while still answering specific questions at all the various forums....
Let me start out by saying this thread is a "This helped fix my concerns and issues with my PSA Gen II Nitrated, Nickel Boron BCG 18" Carbine." The thread is not a negative post about PSA in any way.... so if someone just wants to complain, please leave it out of here... this thread is about making your heck of a deal rifle run smoother. I am posting this to show what made mine run MUCH smoother... I am going to the range today for its first firing. I will post the results later... I have a lot of stuff to try and get done at the range today. So it finally got here... and I wasn't kidding about PSA building as they get orders !! Also.... as shipped, this is beyond a doubt, the most oil free rifle ever. Everything is bone dry... the best part about that is it makes finding any rough finish / binding parts easier. That is not to say the finish sucks, as a matter of fact, the finish is as good as any of my AR's , Colt , BCM, Rainer Arms, etc. It just needs a little polishing in spots, and OIL... did I mention the lack of oil ? Lol Just as a reference ...Oil used is ALG Go-Juice. As for the polishing... in the past I have found a little burnishing, on various parts can greatly improve the "feel" ... and the PA10 was no exception. 0000 Steel wool , the finest commonly available ( won't even scratch glass ) is what I use. When I say a little burnishing, I mean about a minutes worth. So far, parts minimally polished that show drastic noticeable improvement on the lower. The inside of the buffer tube... it was just rough and gummy (?)... after a spin down the buffer tube with a 0000 steel wool wrapped 12 gauge bore brush, it is much improved, then after a proper OILING on the interior of the tube and on the buffer and spring, it is nice and smooth. The disassembly pins.... burnished and lubed.. improved smoothness. Burnished the outside of the buffer tube as well.... much smoother. Now for the most interesting polished / burnished "part".... the magwell. One of the first things I tried was the mag drop and insertion...Magpul 10,20,25, and 25 M118 wouldn't drop free.. loaded or not loaded. A few minutes of burnishing the interior of the magwell, with little effort given to being through... resulted in all Magpuls dropping free, unloaded and loaded. Worked so well that I don't even feel the need to oil the magwell.............. just kidding, gave it a coat simply because it is bone dry. Again... very little effort to polish up working surfaces only... maybe 3 minutes. I should add, the PSA rubbery hand grip is pretty dang nice. Trigger is typical "MilSpec gritty"... I am going to try the USGI paracord trigger job on it because I want to see if it works. I will measure , with my cheap RCBS trigger pull gauge, the before and after weights.  Paracord AR-15 Trigger Job Straight out of the box, its heft is ok... I was expecting more heft / weight, given PSA's 10.4lb listing.... actual weight... 8 1/4lbs bone stock. The only way I could make it close to the advertised 10.4lbs, was by adding a fully loaded 25rd Magpul and the owners manual and magwell security lock. OAL as delivered....collapsed, 37 1/8ish"... extended 40 1/2ish" I will be adding info as I get time... but so far I feel confident I will like this PA10. |
Various staking appears GTG. The buffer springs and tubes are same OAL as AR15 carbine parts.... but the .308 buffer is shorter and the 308 buffer spring is thicker. Buffers as shown... AR15 carbine buffer, PSA OEM PA10 Carbine buffer, KAK HvyWt .308 carbine buffer 5.5oz that I will be trying out ( I prefer my rifles to have mild recoil impulses. ) And I really need to say again.... this rifle was bone dry.... so prior to shooting your PA10.... at the VERY least, field strip and lube thoroughly. More to come.... including after the OEM configuration test firing, my add on's..... PRS Gen 3 w/ rifle length buffer tube and HvyWt KAK 308 9.3oz rifle length buffer, LaRue Trigger, Tubbs Flatwire spring, maybe a SLR adjustable gas block, etc. I don't know if all those parts are compatible yet. |
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And as for the trigger trick... the PSA supplied trigger is pretty bad, so I figured why not try the trick...results...
After about 7 dry pulls, the grittiness is gone... frankly I am surprised... the OEM pull weight was 7 3/4lbs and after the "trick" a MUCH smoother 7 3/8's lbs. And yes I will fire for reliability and accuracy results prior to most changes... I will install the trigger and finish finessing / burnishing parts. I need to add ... the upper to lower fit is snug, but the pins themselves are slightly undersized.. not enough to really matter, but the fit could be better just from better fitting pins. Also , the OEM PSA charging handle is "dragging" in its channel... already have wear marks from the few dozen times I have hand cycled it. So I have to figure out how to "loosen" that up. Even the BCM Mod 5 drags slightly .... so it is a upper issue, possibly not the charging handles. ( Even the PSA charging handle needed oil on the latch !? ... Haha.. ) |
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I am going to try Fed XM80, MEN, Hirt., FGMM 168gr, GGG, Aust. Outback for the OEM test firing. Maybe other common ammo.... I have a wide assortment already.
They certainly did not test fire it with no powder residue at all, any where that I can see.. As for the charging handle marks... Got that part figured out. The charging handle has no "tab" on the chamber end tip and With no tab ... the charging handle made the whole topside drag and bind.... combine that with the 2 outside guide tabs being snug it was turning the charging handle into a de-burring device. I suppose I could slightly file the 2 guide tabs and make the charging handle a tiny bit looser.... but whatever was removed and the BCM Mod 3 ( I said Mod 5 earlier.. oops ) is working fine. EDIT... and UPDATE ..it wasn't the charging handle at all... it was the gas tube / barrel nut interface causing binding.... and "jamming" up into the BCG gas key. More on that later. |
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I am going to gently polish the feed ramps.... they are scraping up the chambering rounds pretty good.
I am also going to thoroughly clean the chamber, the manually ejected 168gr FGMM rounds.. while extracting good show obvious scratching / scuffing in places I consider odd. 
I am going to get out some .7.62x51 v. .308 and see how well they chamber, etc.... and try the Tubbs Flatwire spring, just to see if it would even fit / "function" in the PA10's AR15 carbine length buffer tube. |
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Next issue.... I can live with this, but a standard Magpul Moe+ grip has a HUGE gap when mounted....I imagine any other AR15 grip will have the same issue.
Most likely I will use some black RTV sealant or something and fill it in. The PSA supplied one fit nicely. and frankly good enough with its rubberized grip.... but I want OD. ( my bling ) Sorry if the photos aren't clear but the camera and I couldn't find the right lighting. NOTE... I changed the safety to a 45 degree ambi... so the photo's do not reflect the OEM PSA one. 
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I should have taken a photo of the black gunk that came out of the chamber... whatever packing oil / rust inhibitor they used on the barrels most certainly needed to be cleaned out to aid in smoother chambering.
I "helped" barely round out the breach end of the chamber with a little polishing compound on a 20guage bore mop attached to a spare rod piece spun by a low rpm drill... more black gunk... and I can physically feel it is smoother now. The previous case marks ( 7.62x51 Fed. MSR had them as well ) are now eliminated... so more burnishing worked. So far ... IMHO, I think with a little QC on my end... any of my concerns are easily "fixed" with very little effort. Up until this point all these QC concerns could have been taken care of in one afternoon... so I am happy with all the results. Oops ... meant to add, a good polishing of the interior of the buffer tube smoothed that up a LOT.... |
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Tonight's adventure was cleaning the barrel.... all I can say is wow... it was filthy.
I decided to try a simple 4-6 pass breach end scrub with a bronze bore brush and just the Go Juice first.... This is what wiped out on the first patch from JUST that light scrub.... Sooo.... be SURE to clean the virgin barrel prior to firing !! I realize most all of this seems fundamental .... but I can't help but wonder how many people skip doing most these items, and then wonder why they are having issues. 
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I have decided to fore-go the feed ramp polishing until after the first firing.
If the feedramps have any issues , then I will try to polish them. ( I do want to see if the OEM configuration is "ok" ) Next, I am going to swap in the LaRue Trigger... ultimately I will want it in there so why not benefit from it now. I am not going to remove the second "O Ring" .. yet.... So far, manual feeding has been fine from a full 25rd Magpul after the various polishing. The Tubbs Flatwire recoil spring fit "better" then the OEM PSA one.... I say better only because it slightly narrowed the overtravel gap between the buffer face and the bolt stop.... OEM distance was about 1/4" and the Tubbs is 3/16"... IMHO 1/4 " is slightly to much, and can lead to bolt stop breakage. My 9MM Colt pattern PCC has proven that.... I can always resort to the quarter/s in the end of the buffer tube if need be. So.... tomorrow will be the test firing. I will have the PA10 in its OEM configuration for all intents and purposes... grip changed, trigger, Lantac brake are the only part changes done so far. I will also try out the heavier 5.5oz shorty buffer, The Tubbs Flatwire, A Tubbs Carrier Weight System ( combined and separately ).. and possible remove an o-ring from the extractor if needed. Test firing will be scoped and 100yds. Later I will change to the PRS stock and possibly an SLR adjustable gas block. Wish me luck !! |
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Ok... everyone gets three guess how many issues I had....
I had zero issues No feeding issues, no extraction issues, no tight magwell issues... Zero.. nothing. I fired at least 300rds, and 20ish makes / brands , and weights from 130-175gr. I am happy with my purchase, at this point I would recommend one of the PSA PA10's to anyone... I will add, seriously, clean the thing, and lube everything. I will be adding the SLR adjustable gas block as well as the Magpul PRS stock. I believe it "kicks" more then needed. Ejection was bouncing out at the 1:30, smacking the case deflector each time with all the brands of ammo. I did try the KAK 5.5oz ( ? ) buffer and it helped very slightly.... but if I did have the wrong .308 carbine buffer spring ( Mentioned on one of the other forums ) then the results could be skewed. I did also try the Tubbs Flatwire with the heavy 5.5oz KAK..and the Tubbs CWS ( adds even 4.6oz more ) ... still ejecting hard forward... no real noticeable difference. After my photos finally come through... I will post photos of the various groups... please do not judge the round counts in the various groups... I frankly didn't think the day would go so completely smoothly, so my "plans" changed and I adjusted as needed. So some of the groups are 7-8 rds, some are 10, some are 20.... and frankly, some are so poor ( SSA ammo ) that I had a heck of a time figuring out where the shots were even hitting ! Welp.... the KAK heavy rifle length buffer ( 9.3oz ) showed up today as well !! I will be swapping over to the Rifle length stock asap.... and firing again tomorrow. Another side note... if you are considering a B.A.D. bolt release lever.... forget it... the is not enough room between the upper and the paddle for the BAD lever. |
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Various ammo accuracy results... OEM stock pretty much sucks for reasonable bench shooting, IMHO.
100yds, benched, scoped Primary Arms 4-14 x 44, bagged front and rear, reasonably slow steady fire. And the recoil with it being overgassed is not helping ... so use your best bench techniques if you are going to stick with it being overgassed. I am confident, that after changing to the SLR adjust. gas block and the Magpul PRS...it will be "easier" to achieve better groups. Rifle configuration when these groups were fired...( So I remember ) OEM parts...Carbine buffer system, buffer spring, gas system, upper, lower, BCG, barrel. Add-ons... KAK 5.5 oz, LaRue trigger, Magpul MOE+, Primary Arms 4-14 scope, tried the Tubbs Flatwire, and used the Tubbs CWS. OEM various groups..... First the ugly...the red pasters are right at 1 inch In order as they appear.. OEM Nitrated barrel accuracy , just as it came from the factory... Black Hills 175gr TMK.. 
ZQI Ball FMJ 
CBC/ Magtech Ball FMJ 
SSA Accubond 165gr... NOTE the much smaller group is not part of the SSA. the bigger then my hand group is the SSA... including the 2 out in the black pasters !! 
Win. 147gr Ball FMJ 
Eagle Eye 175gr SMK... ( way to hot of a load, I could feel it, and the brass case head showed nasty smears etc. ) 
Black Hills 168gr SMK Moly coated.... not bad for 25+ year old ammo. 
Hornady TAP ELD Match 168gr 
Hornady TAP ELD Match 168gr "AR" 
FGMM 168gr SMK 
GGG 146gr Ball 2013 production 
MEN Ball FMJ 
Hornady Steel Match 155gr... Lacquered 
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OEM Nitrated barrel accuracy , just as it came from the factory...
FGMM 168gr again 
1983 Hirt surplus Ball FMJ 
Fed. M118 LR 175gr SMK 
Aus. Outback 165gr SGK SP 
Aus. Outback 168gr SMK 
PMC XTAC 168gr Match 
Fed. XM80 
Fed 130gr OTM 
FGMM 168gr rapid fire ( as fast as comfortable , and back "on" aiming point. ) 
PMC XTAC Ball FMJ 
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Reading through this thread again, I'm a bit bummed to see your tubbs flatwire spring, and H3 buffer didn't help with the overgassing issue at all. I was planning on getting both, since mine is ejecting at 2 o clock right now.
Mine was "kicking" a bit much as well. I put a strike industries j-comp on, and it's actually pleasant to shoot now. |
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Ok... finally got some time to install the SLR adjustable gas block ... easy job, Right ?
I bought the dimpling jig, so truthfully the SLR block install should be very easy..... and the gas block install was easy.. but... Enter PSA's Freefloat tube barrel nut and the PSA gas tube..... ( pics will follow ) I haven't built a lot of AR's , but, I do know.. the barrel nut should NOT force the gas tube into the uppers gas tube "hole" top portion. The gas tube is in full contact with the front of the barrel nut... enough so that it has eroded / scrapped away the finish on both the nut and tube . Ultimately, IMHO it would have wore a hole / weak spot into the gas tube.... it has that much contact. The top portion of the gas tube end, where it engages the BCG gas key, also shows more wear then the bottom with just my eyes. Also, I do know that you want the gas tube to move "somewhat" freely through the uppers hole. Any binding of the gas tube can affect overall / consistent performance and accuracy... ( you don't want ANY binding ) you really want the rifle to consistently return to battery, effortlessly, the same way every time. The photo shows the spot where the contact is , the little wear spot... the larger edge wear is from me sliding the rail free. More photos will follow... at this point I am going to dremel down the area that has no contact with the rail and see how well the gas tube fits after that. 
Oops... gas port was centered perfect with the gas block... as near as I can tell minimum gas port size is .0725+. No barrel dimpling, and the gas block screws were just screwed tight. |
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Normally I wouldn't "Dremel gunsmith" but it is a cheap aluminum barrel nut and handguard.
This is how close...notice how one end you can see light through... and the other end you cannot. I ended up having to shave the top its full length... whoopee !! I will post photos of the after the fix later. Hand assembled shows much better clearance. 
If you look close.. you can see the top of the tube is firmly pushed up, the sides have clearance. 
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IMHO, I think it was really about the PSA gas block and gas tube not fitting well at all with the PSA barrel nut.. after installing the SLR block and a higher quality gas tube the clearance is much better.
So much better, that I have to wonder if the gas tube cant was also involved in the original PSA charging handle binding problem !? I will check later to see if the PSA charging handle and BCG no longer binds up so bad. Kind of excited to try the adjustable gas block. I will also try the heavy 9.3oz buffer with the gas block fully open to mimic the OEM configuration... and then adjusted lower. I hope the standard rifle buffer works best, ( with the SLR block ) since there is no reason to have a lot of mass banging around Next... the bolt catch paddle is banging the upper ... Dremel time for the back side of the paddle !! 
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Clearance nowafter grinding... I did have to grind the whole top of the barrel nut, front to back, that's how much interference there was.
Grinding the front only just moved the contact point further down the nut.... clear to the receiver end. The gas tube now has "wiggle" room and frankly, feels easier to hand cycle. 
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Where to start.... The Adjustable gas block, what a difference ! I whole heartedly recommend the SLR adjustable gas block, it truly transformed the abrupt cycling PA10 GenII into a smooth cycling .308 rifle. Ended up using the 5 clicks from fully closed setting, 10 more clicks ( opening the gas flow more ) were available.
I used the standard weight PSA PA10 rifle buffer for the accuracy and function testing first 4 clicks failed to cycle 2 of 20 rounds of FGMM .308 168gr, and 5 of 40rds of ZQI, 2 of 20 Horn. TAP "AR" ( ... 5 clicks performed 100% with the FGMM, ZQI ) The Hornady TAP "AR" needed 6 clicks to cycle with the KAK AR10 9.3oz heavy rifle buffer. Interestingly, at one point while firing the Horn. TAP AR round , I adjusted the gas block one additional click wider, and the point of impact for the next 10rds shifted 2 inches down and 2 1/2 inches left ?! .... It is just as possible that I "shifted" as well... but 10rds makes it hard for me to think it was just me. ZQI also performed miserably accuracy wise ... again. At 5 clicks and the rifle fired approx. 300rds trouble free. ( Except the later heavy buffer tested 2 Horn. rds. , with the standard rifle buffer it was fine ) The brass caseheads no longer show smear marks from the ejector, which is directly attributable to the "slower" ( milliseconds slower ) speed of the action. Pressure levels have dropped more prior to extraction...and because of this... the case has a moment more time to lose the chamber gripping PSI prior to extraction. The new replaced by me ..firing pin retaining cotter key is not bent ( I forgot to mention this earlier, the OEM PSA cotter key was getting bent from the violent cycling !?!? , I had a replacement on hand so changed it out ) The rifle now feels like a mild 7.62x39 AR.... so it is a pleasure to shoot !! I haven't compared group measurements yet ( from the OEM configuration compared to the current ) ... but I did see improvement, for the most part across the board. I will add.... the GEN 3 Magpul PRS's recoil pad.. while "softer" then the old models, needs the sharp edges radiused more..... by rd 300, it was biting into the shoulder more then needed... I will fix that ! Later on I will post the various ammos groups. |
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Nitrated OEM Barrel with the SLR Adjustable Gas block groups.....
1st Photo....FGMM 168gr... Oddly, the rifle prefers , slow methodical shooting with this ammo. 
2nd photo ...Reasonably rapid fire FGMM... ( bang, back on target, bang ) produces large groups ... not all ammo did this. And My SAI M21 doesn't do this..( It could very well be me learning to shoot a .308 AR ) 
3rd photo.... GGG 2013 Ball.... GGG preferred to be rapid fired.... ( First 5 shots were the tight cluster ) 
4th photo.... as well as the XM80 Ball, rapid fire. 
Maybe shouldn't drink so much coffee and smoke so many cigs, prior to accuracy testing.... Lol |
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Nitrated OEM Barrel with the SLR Adjustable Gas block groups.....
1st photo ..... MEN 2016 Ball 
2nd photo .....MEN 2016 ball again 
3rd photo.../ Aus. Outback 168gr SMK 
4th photo.....( Mislabeled in photo)... Hornady TAP "AR" .... this is the Heavy Buffer group that shifted after "one more click of gas "....first 6 , top right, added click, bottom left 5.... ( Rifles are fussy !! ) 
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Nitrated OEM Barrel with the SLR Adjustable Gas block groups.....
1st photo.... M118LR 
2nd photo... M118LR 
3rd photo... BH 175gr TMK ... my rifle still hates it... ironic that it is so pricey, yet my rifle doesn't think that matters... 
And I just realized I forgot to shoot the Hornady 155gr Steel Match !! Looked at a group ... mislabeled it ... and then saw the mag full of Steel Match !! Arrgh. |
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Just an FYI.... Apparently Magpul makes a different MIAD Gen 1.1 Type 2 hand grip with taller backstraps for the PA10.... I have ordered one up, as well as some of the Brownells $10 AR10 metal mags to try out.
"* NOTE: This TYPE 2 Kit uses taller backstraps for optimized fit with certain 7.62x51 receivers such as the Armalite AR-10A/B/T, DPMS LR308, KAC SR25, LaRue OBR, LMT .308 MWS, Palmetto PA10, and S&W M&P10." https://www.magpul.com/products/miad-gen-1-1-grip-kit-type-2 |
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This.... Sadly...at this point I would not buy more Brownells 20rd .308 mags at even $5 a mag.... even if a little filing at the latch helps.
I just received mine, unloaded, ....width 1.0645..... snug fit in magwell..... locks in well , bolt closed.... does remove freely ( not quite drops free ). Loaded 20rds easily..... width 1.099... tight fit in magwell.... have to VERY FIRMLY smack the bottom to get it to lock in ( even after filling some of the OAL of the leg off of both the front and back of the follower..... and it will not drop free, ( while fully loaded.. period. ) I will try to lightly file the mags latch area, in order to make insertion easier.... but, I think the ultimate problem is the feedlip spread, since unloaded it snapped into place easily. Function was 100% hand cycled. Pull back charging handle.. let'r fly into battery. |
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I'm surprised you only need 5 clicks with a rifle buffer. I'm running my PA-10 (Faxon 16" pencil barrel and SLR gas block) at 6-7 clicks out with H (3.8oz) shorty buffer shooting weak M80 ball. I started at 4 clicks and worked up to 6-7 until reliable lock back.
For grips, I tried a bunch and found the BCM Mod3 fits pretty well (still has slight gap under the beavertail, but MUCH less than the others). Mine also works well with both Pmags (not really a fan of them) and IMI Defense windowed 20's (my favorite's for cost/reliability). I'll eventually pick up some L7's, but their price is a hard pill to swallow. Great thread and keep up the updates! Oh! Also wanted to give a heads up that Odin Works M-lok "LOW" height rail fits like a glove (best rail I've ever used)! I went with the 15.5" and it's superlight yet seems very rugged. I also LOVE how it mounts (uses a collar/adaptor that threads onto the receiver threads, barrel goes into that, then a nut internally threads into the collar to lock it down. The collar also has a raised portion with hole through it that acts as an extended gas tube guide. It's brilliant. Not only does the collar/nut lock down super secure, but the gas tube, itself, will still be a back up to prevent rotation, just as a mil spec barrel nut does). Just a note if you use that system though, you will need to file down the dust cover rod as it protrudes too far forward to allow the collar to seat close to the receiver. Also, with the Odin Works, do NOT use grease on any of the threads. The collar should go over dry receiver threads (because it needs to grip those) and the nut uses vibra-tite (which is like a flexible, non permanent, thread locker). This is important to assure it stays rock solid... and it DOES when installed correctly (no lube/grease). |
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I'm surprised you only need 5 clicks with a rifle buffer. I'm running my PA-10 (Faxon 16" pencil barrel and SLR gas block) at 6-7 clicks out with H (3.8oz) shorty buffer shooting weak M80 ball. I started at 4 clicks and worked up to 6-7 until reliable lock back. For grips, I tried a bunch and found the BCM Mod3 fits pretty well (still has slight gap under the beavertail, but MUCH less than the others). Mine also works well with both Pmags (not really a fan of them) and IMI Defense windowed 20's (my favorite's for cost/reliability). I'll eventually pick up some L7's, but their price is a hard pill to swallow. Great thread and keep up the updates! Oh! Also wanted to give a heads up that Odin Works M-lok "LOW" height rail fits like a glove (best rail I've ever used)! I went with the 15.5" and it's superlight yet seems very rugged. I also LOVE how it mounts (uses a collar/adaptor that threads onto the receiver threads, barrel goes into that, then a nut internally threads into the collar to lock it down. The collar also has a raised portion with hole through it that acts as an extended gas tube guide. It's brilliant. Not only does the collar/nut lock down super secure, but the gas tube, itself, will still be a back up to prevent rotation, just as a mil spec barrel nut does). Just a note if you use that system though, you will need to file down the dust cover rod as it protrudes too far forward to allow the collar to seat close to the receiver. Also, with the Odin Works, do NOT use grease on any of the threads. The collar should go over dry receiver threads (because it needs to grip those) and the nut uses vibra-tite (which is like a flexible, non permanent, thread locker). This is important to assure it stays rock solid... and it DOES when installed correctly (no lube/grease). I wonder if the Nickel Boron'd BCG helps that much ? And remember, I did "fix" the binding gas tube . |
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I was just as surprised with the 5 clicks. And that is even with the 9.3oz KAK Heavy AR10 buffer. I wonder if the Nickel Boron'd BCG helps that much ? And remember, I did "fix" the binding gas tube . The Rifle has been flawless for me (reliable lock back, zero feeding/extraction issues), but I am having one issue which I'm not sure is ammo related or not. I'm having occasional failure to fire due to light primer strikes. I'm using the EPT trigger (which I LOVE and use in all my other AR's). There seems to be enough pin protrusion, but it's not punching the primers deep enough for 100% reliability. I asked PSA if the EPT uses standard mil spec springs, and they say it does. So I'll either have to keep shooting it, and maybe it will sort itself out. Or swap in a stronger hammer spring. Or... it could just be unusually hard surplus M80 primers (though a mil spec spring should not have difficulty with that). I'll sort it out somehow (I really should try some commercial 308 to see how those primers do with my current set up). With my shooting schedule, it will probably be awhile before I get around to that rifle again. I'm enjoying your evaluation and modifications thread here! Please keep up the good work and keep us posted! Thank you for taking the time to share your findings with us! |
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When you say weak M80 ball ammo.... which brand ?
The fact that ZQI required an additional click to function properly , just shows me that ZQI uses a faster burning ball powder ( one that doesn't quite produce as much gas as other brands , hence it needed more volume of gas into the action )... kind of like IMR4198 .223 loads... looks good on paper, but really not the best choice of powder for a gas gun. Also some M80 has "harder" primers. |
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When you say weak M80 ball ammo.... which brand ? The fact that ZQI required an additional click to function properly , just shows me that ZQI uses a faster burning ball powder ( one that doesn't quite produce as much gas as other brands , hence it needed more volume of gas into the action )... kind of like IMR4198 .223 loads... looks good on paper, but really not the best choice of powder for a gas gun. Also some M80 has "harder" primers. |
| Good write up, you would think it would be common sense to thoroughly clean ANY new gun prior to use and go through and polish up and clean any machining burrs especially on a cheaper rifle like most of these are, but it doesn't matter if I buy a $200 or $3,000 gun the FIRST thing that I do is a complete disassembly and cleaning / de-greasing before use, basically following the same steps as you and I haven't had any issues with a gun I have gotten besides a century AK but that thing was wayyyy out of spec. Good tip on the buffer springs. |
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Good write up, you would think it would be common sense to thoroughly clean ANY new gun prior to use and go through and polish up and clean any machining burrs especially on a cheaper rifle like most of these are, but it doesn't matter if I buy a $200 or $3,000 gun the FIRST thing that I do is a complete disassembly and cleaning / de-greasing before use, basically following the same steps as you and I haven't had any issues with a gun I have gotten besides a century AK but that thing was wayyyy out of spec. Good tip on the buffer springs. I have ordered another SS 18" barreled upper for parts ... ( BCG, etc... price was $400 delivered ) so we will see how this one is. I will eventually change the barrel in one or the other... accuracy is "decent" from the nitrated barrel...but I want better. .308 ammo is so expensive... I'd rather have better accuracy at minimum 50 cents a shot..... a decent barrel is as much as a case of Malaysian surplus. Times are great for parts !! |
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.308 ammo is so expensive... I'd rather have better accuracy at minimum 50 cents a shot..... a decent barrel is as much as a case of Malaysian surplus. |
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Relegate your least accurate upper to steel. Everybody needs a knock-around 308. When you feel like going out blasting, when you can get Wolf 308 at 35 cpr, why would you ever shoot wimpy 223 at 30cpr? That's the theory that had me pick up a PA-10. :) Hopefully someday it'll actually work... I think I will check into some steel cased SP's and check the performance, both accuracy and expansion wise.... ( this cheap hobby just keeps getting more expensive.. Lol ) |
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Ok... while I am happy with the rifles performance, eventually I will want better accuracy. Criterion, Krieger, Bartlein barrels or such..... 18" 1n10 twist or a 20" maybe.
So, I ordered another upper... in SS.. 18" ( one of the two will be a parts donor to my better barrel.....) between the 2 uppers, which ever is less accurate will receive the new barrel. My M21 and My Krieger barreled AR15 will shoot most all ammo "better" ( those barrels have made me an addict to accuracy ) ... they both have ammo they hate, but for the most part there is a general improvement in overall accuracy ... that is what I'd like with a better quality barrel. The issue with the M21 is it only holds great accuracy for about 150rds before the groups open up ( seems to be related to the gas piston and fouling )... a good cleaning will restore the accuracy, but the Krieger AR15 doesn't do that.... I am hoping the AR platform in .308 ( with a decent barrel and a little finessing.. trueing the receiver face and a properly headspaced bolt ) will yield the results I would like. At this point, I am strongly considering a 18" or 20"Criterion rifle length gas. The price is good and the reputation is very good. |
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Well.... I ordered up the "better" barrel today....
Criterion 18" Middie.... https://msrarms.com/collections/m-o-t-m/products/criterion-barrels-nitride-finish-stainless-steel-hybrid-contour-barrel-308-ar?variant=29092302337 And ordered the Brownells version of the Geissele reaction rod and JP Upper vise blocks. After shooting again on last Sat. ... I couldn't bear the thought of shooting so much expensive ( compared to 5.56 ) .308, and accepting the PSA barrels accuracy level ( really , Lack of accuracy ). Criterion said the barrel should fit just fine, but did caution me about using a Nickel Boron Bolt... the reason being .. A. Quality of the application of the NiB, ... B. Since it is a coating, headspace could be excess as it possibly wears off / flakes off the locking lugs or bolt face. ( NOT saying the PSA bolt will... just making note of the coatings impact on dimensions ) Interesting... I had never thought of that. Granted if the bolt was produced properly, it should be a-ok. For me... that is another reason to use a conv. bolt or a nitrated bolt... or at least one that is not a coating. |
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Relegate your least accurate upper to steel. Everybody needs a knock-around 308. When you feel like going out blasting, when you can get Wolf 308 at 35 cpr, why would you ever shoot wimpy 223 at 30cpr? That's the theory that had me pick up a PA-10. :) Hopefully someday it'll actually work... |
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I received the SS Barreled Upper today from PSA...18" middie, FF, SS barrel, Nitrated BCG
http://palmettostatearmory.com/psa-pa10-18-midlength-308-win-1-10-stainless-steel-15-m-lok-upper-with-bcg-and-ch-516445088.html Weight of just the upper, from the PSA is 5 1/3lbs I has the same gas tube binding issue the FF Barrel nut and the BCG... exactly the same. ( The barrel nut makes contact with the gas tube, forcing it in to the top The gas key is properly staked... just like the first. The charging handle lacks the raised "tab" at the front of it.. just like the first. The upper is also bone dry...no extra oil at all... a very slight amount of something on the BCG. Going to change the gas block to an SLR adjustable, grind down the barrel nut flat to allow free movement of the gas tube, oil it up, use a BCM Gunfighter "Brake" on this barrel and see how it shoots. I am hoping for better accuracy then the nitrated barrel has done, and will be reporting more info as I get it. Again, which ever upper shoots the worst, will receive the Criterion replacement barrel. ( I have high hopes for much better, consistent accuracy ) Photos of its OEM state will follow. |
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This is the new 18" SS upper....
The first image is with the OEM gas block loosened and pulled back so everyone can see how much the barrel nut was pushing the gas tube up, it would not freely enter the gas tube hole at all... as a matter of fact it took a fair bit of gentle pushing to allow it to go in. 
The second image is with it entered into the hole in the receiver... note how much it is flexed at the front of the gas block. 
Third photo shows the wear from the OEM install and me taking it on and off... the little shiny spot on the edge. 
Fourth photo shows the clearance now after grinding off material along the entire top... free movement and clearance. 
I will add... the gas tube was binding the BCG ( via the gas tube interaction ) the same way my first nitrated barreled upper was. Again That binding will not help accuracy and function ( let alone longevity of parts ) at all. So if yours is like the first photo... fix it for your own good... I'd bet you'll be happy you did. |
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I will add... the gas tube was binding the BCG ( via the gas tube interaction ) the same way my first nitrated barreled upper was.
Again That binding will not help accuracy and function ( let alone longevity of parts ) at all. So if yours is like the first photo... fix it for your own good... I'd bet you'll be happy you did. |
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Was bending the tube upwards to clear the nut not feasible, rather than grinding the nut? Seems that any length lost by re-bending the tube for clearance would help the binding problem you mentioned, unless I don't understand the 'gas tube interaction' to which you are referring. And the entire top edge was causing binding, all the way to the uppers gas tube hole... so IMHO it was better to leave the gas tube in its "natural" state and just grind the barrel nut down. I am comfortable with the little amount I removed... it was so little that the barrel nut is just fine. |
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Which SLR adjustable gas block did you get? http://slrrifleworks.com/index.php?route=product/product&path=57_103_168_104&product_id=124 |