PSA PA10 GenII comments and observations.

[bfoosh006]

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Posted September 5



Well.... that was very uneventful !!!

The PSA barrel nut was a breeze to loosen up on the nitrated upper !!

WD-40'd it let it soak for about 5 min. and a reasonable pull was all it took. ( Heck I have turned bolts tighter then this one )

IMHO, it was snug enough... but not Gorilla'd on like I expected !

JP Vise blocks worked perfectly for this upper.

The barrel freely moved out of the upper.



So much for worrying about some thing needlessly !!



Next, I will true up the receiver face..... most likely "glue / lock tight" the Criterion barrel in place and torque it down.

 

[bfoosh006]

Checking the headspace w/ PSA Bolt and Criterion barrel.... bolt will close and lock on FGMM .308 , CBC 7.62x51, and Hirtenberger '76 7.62x51 ball....

Bolt will NOT close or lock on a Forster NO GO gage.



1st photo....trued the receiver face ..... ignore the haphazard grind marks from the "flattening of the barrel nut"

2nd photo... shows the different barrel profiles... PSA at the top, Criterion SS Nitrated .308 Hybrid Barrel on the bottom

( Criterion Model 1018S-HYM-N...18"... 1-10 RH twist ... 5/8 x 24 threaded muzzle.... .750 gas journal... Mid length Gas system.... Criterion 308 WIN M118 chamber )

3rd Photo... PSA on top.. Criterion on the bottom

4th Photo ... PSA on top ... Criterion on the bottom

 

[bfoosh006]

Posted September 5



Comparing the fit of the two barrels into the upper receiver.... the PSA barrel shows some slop in the barrel extension to upper receiver....

Using just my hands you can feel a definitive " light thunk" while holding the PSA barrel snuggly into the receiver and shifting the barrel side to side and up and down... interestingly, it is most pronounced up and down..... the Criterion barrel shows MUCH less movement.. in any direction.

I will try to mic both and see what the measurements are.

After hand fitting all the parts together, and slightly snugging the barrel nut on the Criterion barrel ( Not fully torqued ) ... I have hand fed numerous .308 rounds and 7.62x51 rounds... all have fed perfectly... from the Magpul, Lancer ( still the strongest mag spring of all the mags ) , the D&H and even the Brownells.

I will use the Loctite 609 Retaining Compound ( from the Criterion video #3 ...https://www.youtube.com/watch?v=XHxU8VUAHOY&index=3&list=PLqwwk7tC6Sdanx0b55g2EL8UV5udC2Gwh ) .... when I install the barrel, following their guidelines.

BTW.. I have read on numerous different threads around the internet ... that PSA doesn't lube their barrel nuts... this one was 100% lubed.

 

[bfoosh006]

"This is a very informative thread. I am picking up a PSA Gen2 complete lower this afternoon and will being building around it, and I've picked up a lot of interesting bits of information from your notes.

Can you reiterate why you installed an adjustable gas block? "



My main reason for the adjustable gas block was the cyclic action of the PSA... it was needlessly over zealous.

I do think the PA10 GenII has a "industry standard" gas port size... but also believe it is slightly bigger ( more gassed ) then needed or wanted... ( at least by me )

USGI weapons are usually overgassed so they will work in the most awful conditions possible.... full of muck, no lube or cleaning for ages.. etc... so they really want the firearm to cyclic "no matter what".

My .308 AR will most likely never see severe conditions like that ( I could always increase the gas anyhow.. ).

So by using the adjustable gas block, I can limit the available gas volume, and have a fully functioning , softer shooting, easier on the brass and rifle parts, stay on target quicker, more pleasurable .308 AR to shoot.

The difference between the OEM non-adjustable and the SLR adjustable gas block configured rifle was "night and day"...

The brass cases were not showing signs of violent, still under high pressure extraction after tuning the SLR... ( 5-6 clicks of 12 available )

IMHO, the mere fact that the PA10 GenII will function 100% with , lets just say for the sake of argument, half of the gas of the OEM configuration tells me I did the right thing....remember I am even running a Tubbs .308 Flatwire and a 9.3oz HEAVY rifle buffer with that setting....

Out of all the changes I have done to the firearm... the adjustable gas block was by far the best improvement.

To quote someone on another forum... It changed the firing of the rifle from "Linda Blair" in the Exorcist movie to a calm, controllable Winnie the Pooh.



I whole heartedly recommend the SLR Adjustable gas block... so much so that I bought 2 more shortly after see how much improvement it does.

Much better then just adding weight to the buffer, and or more powerful recoil springs... frankly, if I did it over again... I would skip the KAK 9.3oz buffer completely... and use the adjustable gas block to control the OEM over zealous recoil.



On a side note....a lot of people say the recoil isn't bad.... I am 250lbs 6' and can certainly handle the OEM recoil... but have never understood why I should have to ? IE... if I could make your .308 AR recoil like a much smaller caliber, why wouldn't someone want that ?...

The benefits of the SLR ( a quality adjustable gas block ) far out weigh the added cost.... you will enjoy every aspect of a adjustable gas block.

If anyone orders one from SLR... be sure to consider the 2mm Bondhus wrench they sell and the barrel dimpling jig ( used mine on 4 barrels now ) it took all the guess work out of the install.



I hope that answered your question ... if not , feel free to ask more.

 

[bfoosh006]

hillpitcher2006 ..... this link has some good input as well...

http://bulletin.accurateshooter.com/2015/05/what-makes-an-ar-accurate-whitley-offers-answers/

"9. Gas Port Tuning: You want to avoid over-porting the gas port. Being over-gassed makes the gas system pressure up earlier and more aggressively. This causes more impulse, and increases forces and vibration affecting the top end and the barrel. Tune the gas port to give the amount of pressure needed to function properly and adequately but no more."

 

[bfoosh006]

Posted September 7



I installed the Criterion barrel today as per Criterion's video, used the Loctite 609, lubed the barrel nut with anti seize, torqued it to 50 ft/lbs , Blue Loctited the gas block screws and torqued to SLR spec.

I then checked the headspace, with the ejector and extractor removed from the bolt.... closed on a "Go" gage and would not close on a "No Go" gage... even with a little nudge / pressure on the BCG assist......( BTW... the SS PSA upper with the OEM barrel was the same )

With the hammer removed , I hand cycled various .308 and 7.62x51 ( 10 different, 5 of each cal.) brands through it , each brand from a fully loaded 20rd mag, all fed and extracted fine... except the 2016 MEN.. 2 of those 20rds were snug extracting... and the bolt went fully into battery.

Are those two rds something to be concerned about ?.... I think I will open another couple of 20rd boxes, hand cycle them and see if it happens again.



As per Criterions webpage..." These barrels feature an M4 barrel extension and M118 LR match chamber compatible with both 7.62x51 NATO and .308 Win ammunition. "

Here is the explanation on the "M118LR Match Chamber".... https://sierrabulletsblog.com/2017/06/13/the-m118-lr-chamber-the-223-wylde-of-the-308-ar-world/ ...it is similar to a .223 Wylde chamber design.... I feel comfortable with the M118 LR match chamber.

I will measure the neck diameter on the MEN ammo and compare it to the other rounds...

I would like to test fire it this weekend.

 

[bfoosh006]

"survivalshop said:


Once the Bolt seats with the Barrels locking Lugs , it should loosen up , so to speak . Feeding & extracting certain live ammo may have issues extracting on a new build , shouldn't have any issues with the Action when the ammo you feed is fired . Keep it well lubed for the first hundred rounds or so .

Criterion is my main brand of Barrels for the 308AR , that chamber works very well indeed . "



Thank you.

With no mil-spec I was kind of concerned...( parts fitting wise ) but you are right.

 

[bfoosh006]

So I received the IMI 20rd mag and the C-Products 20rd mag....

The IMI is GTG, 100% function, drops free loaded and unloaded, holds all 20rds, has just the right spring pressure.... and is OD Green..

The C Products is... rough cycling almost like it was binding with the BCG holds only 19rds if you want it to seat in the PSA PA10, doesn't drop free at all, the follower looks like something I whittled out of plastic, is NOT anti tilt .. and frankly looks like it uses a M14 mag spring, seriously....I can't say I will buy more C-Products mags.

 

[bfoosh006]

Posted Sunday at 06:13 AM



As for the testing of the new Criterion barrel, a much more detailed "report" is coming.... but, to cut to the chase, it shot most everything better and I couldn't be happier. No problems at all with the Criterion barrel.

I was at the range from 08:00 - 15:30... fired 100's of rounds, and still got nice, predictable small 10rd groups from its favorite ammo at the end of the day.... with no cleaning at the range at all... the rifle ran 100%.

I fired all the different types of .308 / 7.62x51 I had with me.... I am guessing around 30-40 different rounds. 20rd or 10 round groups.

The Lancers with their stiff springs ( probably not helped by the gas block settings ) caused sluggish feeding.... but all the other mags ran like champs... especially the P-Mags, D&H, and the IMI.

One other brief highlight was the ZQI ammo no longer shots like a 25yd duckbilled buckshot pattern.... it is not a small group... but it is better.



Also, while I am confident the new Criterion barrel helped with the group flyer issues... I can't help but wonder if trueing the receiver face and using the Loctite 609 helped with flyers.... I could see if I messed up the shot.

I started realizing that the "flyers" were a result of me, more often than not, because of my poor bench skills....IE, not maintaining proper rifle holding skills.

I guess what I am saying is.... true up your receiver faces and use the Loctite 609... I will even pull apart the 18" SS upper and do the same thing to it.



I seriously mean it when I say thanks for all the help from this forum and from all you guys... you all helped instill confidence and offered help with a helpful demeanor, something that lacks at other forums sometimes... no one here ever looked down on the lowly PSA PA10 GenII.

After some morning coffee and such, I will start photographing and reporting

 

[bfoosh006]

New Criterion Barrel shooting results... Please bear in mind at this point I am more interested in 10rd or 20rd groups, fired at MSR speeds... IE , on target, fire, back on target, fire, .... no barrel cooldown, or cleaning.

First off, the barrel was 100% GTG in all aspects... no issues with its performance, or its install, as a matter of fact I couldn't be happier with it. The online Criterion Barrel install video is excellent and I installed it just like it shows. ( Video # 3 )

I allowed the Loctite 609 about 35+ hrs to dry... prior to shooting.

http://criterionbarrels.com/media/videos/accurizing-the-ar-15-video-series

Kudos to Criterion barrels for a those videos.

I do think the trueing of the receiver face and the Loctite 609 are important, and easy to do, if you have the barrel off.

I suspect Criterions knows what they are doing , Lol ... and the benefits are less flyers and more consistent group sizes.

I could tell when I was screwing up a group.... and really couldn't fault the PA10 GII for those flyers.



Here are the first groups of the day.. ( I did fire 6 rounds to get on target )



1st photo, FGMM 168gr, 6rds

2nd photo, FGMM 168gr, 5rds or 6 ?.. I don't remember, I was to excited to try more ammo.

3rd photo, 20rds BH 168gr Moly coated

4th photo, 20rds Fed. M118LR, happy about this one because I got a great deal on these from PSA ( $300 / 500rds. ..way back when )

5th photo, 20rds rapid fire 168gr FGMM... most of them went into that ragged hole !!

6th photo, 10rds Atomic 168gr Nosler

7th photo, 10rds Malaysian ball

8th photo 20rds 2016 MEN ball

 

[bfoosh006]

Posted Sunday at 09:08 AM



2nd Target results....



1st photo, that gawd awful ZQI...19rds shown, 20 fired... the first was so off my zero.. I had to find it. Much better performance then before... but still kind of.. well, sucks.

2nd photo, 8rds more 168gr FGMM , I was curious if my grouping had shifted after the first ZQI shot... so this was off the fly.

3rd photo, 20rds Fed. AE 168gr M1A

4th photo, 10rds Winc. 147gr White Box ball

5th photo, 16rds '83 Hirt. ball, boxer primed

 

[bfoosh006]

3rd Target...



1st photo, 10rds South African Ball , the stuff from those tubs.

2nd photo, 19 of 20 shown, Current CBC / Magtech Ball.. kind of all over the place photo missing the one off target on top

3rd photo, 9rds PMC XTAC 168gr Match

4th photo, 15rds ? , Hornady Steel Match 155gr OTM... I have gotten great results with this and the .75gr .223 load.. so steel cased ammo can shot.

5th photo, 20rds '76 Hirt. Berdan Primed.

6th photo, 10rds, Aust. Outback 165gr SGK, soft point.

7th photo , 20rds, Sanitized DAG

8th photo, Eagle Eye 175gr.... only 5 shots... the barrel and this did not play nicely together... almost pierced primers and obvious signs of pressure. More photos later.

 

[bfoosh006]

4th Target...



1st photo, 20rds Port surplus Ball, also from way back when.

2nd photo, 14rds Hornady brass cased 155gr Match

3rd photo, 10rds Horn. TAP ELD 168gr "AR"

4th photo, 10rds SSA 165gr Accubond.. this shot MUCH better ( through the Criterion ) then both the OEM barrels results .

5th photo, another spot check with 168gr FGMM

6th photo, 10rds Fed. MSR Fusion... IMHO excellent performance from and great bonded bullet.

7th photo, Fed. 130gr OTM.. labeled T762TNB1

8th photo, SSA 150gr Accubond ... much better ! ... mislabeled as DAG

 

[bfoosh006]

5th Target... long day of shooting and I could tell I was getting tired.

Also a special note about the last group pictured... 7rds of 168Gr FGMM... this group was from a filthy barrel... and the Criterion barrel could still shoot as good as when it was clean.



1st photo, 10rds Black Hills 175gr TMK

2nd photo, 10rds Speer / CCI 150gr Gold Dot

3rd photo, some more cheap Malaysian berdan primed

4th photo, Speer / CCI 168gr Gold Dot

5th Photo, Sanitized DAG again.... still holding its accuracy , even from the dirty barrel.

6th photo, another FGMM group, rapid fire.

7th photo, Horn. TAP ELD 168gr Precision

8th photo, This, to me is outstanding performance from the Criterion barrel.... final group of the day... after a full 30cal can, and 1 quart ziplock bag worth of spent ammo cases.... The Criterion barrel still shot like it was sparkling clean. 7rds 168gr FGMM..( I stopped with 7 because I thought I'd fubar such a good group ! Lol )

 

[bfoosh006]

The Eagle Eye 175gr SMK ammo issues....

Sadly, this ammo and barrel combo didn't like each other.

Clear signs of over-pressure... and pierced primers, ( I can blow air through each case ) the little primer indentation disc wasn't allowed to "pop out". ( You can't see it clearly in the photos )
I will attribute the fact that I didn't have popped primers and those little disc's to a very heavy buffer ( 9.3oz), the added spring weight with the BCG closed from the Tubbs spring and an adjustable gas block... those 3 parts "retarded" the typically violent/ rapid cyclic action of the OEM configuration by just enough milliseconds to allow BCG movement and extraction at a more moderate chamber pressure.

 

[bfoosh006]

"A few questions:

1. You mentioned earlier on seeing that the firing pin retaining cotter spring was bent and you replaced it - ever figure out why that happened?

2. I've read elsewhere that the clamp style gas block is preferable to the set screw style, due to less (or more even) pressure being put on the barrel. Is this only a concern for a true precision rifle and not something to be considered with a "budget" AR?

3. Is it worth buying the gauges to test head space with any new AR? Or only if you're experiencing cycling issues?

4. You've done a lot of ammo testing on different days with different barrels. In your opinion at this point what's the best non-match grade ammo (ie relatively affordable) for this rifle (with stock barrel)?

Thanks! "






1. I think either the cotter key was soft, or the OEM violent cyclic action was messing with it... the new cotter key with the adjustable gas block is fine.



2. I have wonder about this myself... it of course makes sense... but as long as you do not torque the heck out the screws, ( another good reason why you should dimple the barrel, spreading out the force from the tipped screws... ) I would think you are fine. I have seen way to many USGI barrels with their tapered FSB pin hammered in tighter then Heck ( also applying force to the barrel ) .. fire spectacular groups.

Maybe on the 6.5 Creedmoor barrel ( I am strongly considering ) I might use a clamp-on.



3. Always check headspace !!!
I would, at the VERY least, have a gunsmith check it... having to wait a few days for him to do it is far better then the huge volume of propellant gas blowing up in your face.

Also, since various brand parts don't have to follow a guideline.... you could easily have a headspace issue.

On another forum.... I just saw some Tula that had cracked just above the rim, from a bolt action, it had cracked enough that had the rifle been a MSR... it probably would have been a full on KaBoom... the crack was 1/2 the way around the case head... if a MSR .308 had excess headspace, it most certainly would have been a kaboom.

I realize we all want to go shoot it now... but, step back and seriously consider the possible consequences.... you wouldn't drive across the state with a questionable brake job on your car... so don't do it with something 8" from your face, eyes and such.

Cycling issues can be from all sorts of things... not just a headspace issue.



4. Generally speaking... the Fed. 168gr Gold Medal Match fired quite well from all the barrels.... so do consider the FGMM.

As for a less expensive round... the Sanitized DAG did very well from my barrels. YMMV.

I suggest you buy some of all the cheaper surplus and see which round your barrel likes.... that way you will know for sure it is GTG.

( Barrels are like every person you have ever dated... while similar, they are all slightly different .

 

[bfoosh006]

Next weekend.... I will try and sit down and shoot ... slower, more methodical 5rd groups with the various ammos that show promise.

With a clean barrel .... :thumbup:

 

[clandestine]

Have you measured firing pin protrusion?

The bent FPRP can be the result of overgassing where the gas leaks past the bolt tail and slams into the firing pin flange. This drives it rearward like a piston and bends or breaks the FPRP.

Im also not a fan of scraping the bolt tail to remove carbon, nor using tools to scrape carbon as they can reduce the diameter of the botl tail which will allow more gas to blow by.

 

[jr88]

On the shooting with the new barrel. Do you let tour barrel cool off in between those rounds/groups ? No "break-in" procedure ? I can never get more than about 40-50 rounds done in a day with break-in off barrel.

 

[bfoosh006]

Have you measured firing pin protrusion?

The bent FPRP can be the result of overgassing where the gas leaks past the bolt tail and slams into the firing pin flange. This drives it rearward like a piston and bends or breaks the FPRP.

Im also not a fan of scraping the bolt tail to remove carbon, nor using tools to scrape carbon as they can reduce the diameter of the botl tail which will allow more gas to blow by.

I have not measured the firing pin protrusion.
I will add the other OEM barrels showed signs of high pressure with the Eagle Eye ammo as well.