Pa-10 reliability upgrade help

[MDWeaponry]

33 minutes ago, 98Z5V said:

No, it's not the same as the Armalite AR-10 Carbine recoil system, nowhere close.

7.000" internal depth receiver extensions are AR15 parts, adapted to fit .308ARs.  The major adaptation is a shorter (2.500") carbine buffer and whatever spring whatever manufacturer tells you is their "AR-10 Carbine Spring" - which will end up being bullshiit...

Armalite AR-10 Carbine system was developed with a 3.250" Carbine buffer with three tungsten weights in it (aluminum body), and it weighs 5.4oz.  The Armalite AR-10 Carbine Receiver extension is 7 5/8" internal depth - proper length extension for a 3.250" buffer.  The spring is the Armalite EA1095, and they use the same spring in both Rifle recoil systems and Carbine recoil systems, and it works like a champ. 

Armalite developed this AR-10 Carbine Recoil system, before they developed the AR15 Carbine recoil system.  With the shorter BCG- length in the AR15, they realized that they wanted to use the same buffer body (3.250"), but with steel weights in it instead of tungsten - giving it a weight of 3.0 oz.  That was the AR15 carbine buffer, developed first, as the most important part of the recoil system. Next was, what receiver extension length will that need?  7.000" internal depth carbine receiver extension (official Armalite AR15 Carbine Receiver Extension depth is 6 15/16"...).  After that, they developed a proper AR15 carbine recoil spring...

The AR-10 Carbine Recoil System is far different than using AR15 receiver extensions, 2.500" buffer that you can only get a max weight of 3.8oz with the aluminum bodies, and a garbage spring, probably from an AR15 as well...

My $0.02...

Alright thanks for the information. I’ll order the armalite stuff next week. Now is it safe to assume if I use the quarters mentioned earlier as a temp fix for the recoil assembly, I won’t damage my lower testing it out a bit this weekend?  My receivers are sloppy enough as it is, I don’t need the gun beating itself to death on top of it. 

[98Z5V]

11 minutes ago, MDWeaponry said:

Alright thanks for the information. I’ll order the armalite stuff next week. Now is it safe to assume if I use the quarters mentioned earlier as a temp fix for the recoil assembly, I won’t damage my lower testing it out a bit this weekend?  My receivers are sloppy enough as it is, I don’t need the gun beating itself to death on top of it. 

Shoot it a couple times.  Pull the trigger on it 3 or 4 times,  separate the upper and lower - see if your BCG hit your lower receiver.  You'll know right away if it did - you'll see the impact marks at about 4 o'clock and 8 o'clock.  If it hit, pull the buffer and spring, drop 2 quarters down the tube, reinstall buffer and spring.

If your measurements were right on the money, it won't hit - which is a massive improvement for the PA-10.

[shooterrex]

If Armalite's web site says they are out of the extension kits call them they usually will make you a kit.

[MDWeaponry]

Alright thanks guys. I’ll make sure to take some high tech gunsmithing quarters with me to the range this weekend haha. 

[MDWeaponry]

Okay so it’s not reliability related, but here’s a piece I made out of brass to act as an accuwedge. It wraps around the rear takedown lug. It takes up All the play in the rear, and eliminated 95 percent of the play up front as well. It will last forever, It doesn’t compress, and it will never break apart or jam the action up since it’s stuck around the lug.

[MDWeaponry]

Okay so I decided to take the buffer tube off and file a notch so it can screw in one more turn, and I noticed that even though this lower was considered a gen 2, it seems to be the new gen 3 profile. It has extra clearance cutouts in the buffer tube area. Interesting.

[MDWeaponry]

Just tried the buffer In the tube with no spring and slid the bolt back. There’s no way this thing will hit the receiver even without quarters. I’m sure it’s gonna kick like a mule, but they must be getting the system worked out. I’ll probably still get the armalite tube in the future though just to know for a fact it’s correct 

[98Z5V]

On 8/24/2019 at 1:20 PM, MDWeaponry said:

 but they must be getting the system worked out.

They're not working out any of the problems that their platform has - they're masking the symptoms and hiding evidence of a screwed up design. 

I'm just tossing that out there, so the naysayers can try to counter it.  PSA is spending money covering up problems instead of implementing solutions.

No other lower receiver on the market needs these "PSA Fixes" that they've made up for their awesome new Gen 3...   They say the notches in the lower are to accommodate all the various designs of BCGs...  All those BCGs weren't beating up other lowers... Just PSA parts beating up PSA parts... 

[MDWeaponry]

3 hours ago, 98Z5V said:

They're not working out any of the problems that their platform has - they're masking the symptoms and hiding evidence of a screwed up design. 

I'm just tossing that out there, so the naysayers can try to counter it.  PSA is spending money covering up problems instead of implementing solutions.

No other lower receiver on the market needs these "PSA Fixes" that they've made up for their awesome new Gen 3...   They say the notches in the lower are to accommodate all the various designs of BCGs...  All those BCGs weren't beating up other lowers... Just PSA parts beating up PSA parts... 

 

I completely agree, they may have solved the issue of the bolt beating the receiver up but it wasn’t the proper way to do it. It’s kinda liked they patched a hole with duct tape.

I had a chance to get some rounds down range earlier today, it functioned without any failures for the 40 rounds I put through it, but it kicks way harder then it should for a .308 and the shells are ejecting between 1 and 2 o clock.

Accuracy was pretty decent for the price, about 1-1.5 moa with a basic trigger and an unexperienced scope user behind it (my first rifle with a scope and my first time shooting at 100+ yards).

after sighting it in at 100, I was able to hit clay pigeons at about 150- 175 yards. I hit 8 pigeons with 10 shots and I’m almost certain the two I missed were due to my lack of experience and probably flinching in anticipation of a mule kicking me in the shoulder.

i didn’t attempt any further shots. 

So from my experience today, I need the armalite buffer system, a muzzle break, and possibly an adjustable gas block to tame it down a bit.

for the price I can’t complain but when I can afford it, it will be getting some upgrades.

[RedRiverII]

Funny the differences of experience with the same rifle from the same company.  Original gear and my rifle spit the brass at 4-5 o'clock. Yes a mule kicking sumnagun.  I'm changing the spring and buffer to suggested configuration by 98Z5V.  I'll go to the range tomorrow with two types of ammo.  First experience I shot Fed. GMMK 168's.  MagTech M80 and Fed MGGK.  Wish I had a different muzzle device,  gotta dig through the pile once again and see if I can find one.  I'm holding off on an adjustable gas valve.  I don't plan on shooting suppressed.

[98Z5V]

18 hours ago, MDWeaponry said:

So from my experience today, I need the armalite buffer system, a muzzle break, and possibly an adjustable gas block to tame it down a bit.

You shooting a carbine recoil system or rifle recoil system?  What kind of buttstock is on there?  Fixed buttstock like an A1 or A2, or is it a collapsible stock?

Disregard - I went back through the post and saw the pics.

So, yes, you need the Armalite AR-10 Carbine Recoil System - this one is cheaper than possibly attempting to piece together everything:

Armalite AR10REKIT01 is the part number.

https://www.armalite.com/product/ar10rekit01-6-position-receiver-extension-kit/

Now, this is especially important, right here.  For PSA to get a 20" rifle gas system barrel to even perform and cycle with that superlight recoil system that they put in it, the HAD to make that gas port in the barrel undersized.  You need to take that gas block off the barrel, and verify the gas port diameter - I'll be you need to drill that port UP in diameter, because it's gonna be too small.

Next, where does your gas tube end, inside the upper receiver?  Is should end directly in the center of the cam pin cutout in the upper, which is that half-moon looking cutout space in the upper, the space needed for the cam pin to rotate and lock the bolt in the barrel when cycling.

See if you can get a pic of that put up - a pic straight down into the upper receiver, BCG removed.  Straight down over the end of the gas tube.

Don't make your Armalite Order yet - you'll probably need to add an AR-10 rifle gas tube to the order... 

Edited August 27, 2019 by 98Z5V

[98Z5V]

P.S.   You don't necessarily need a brake on the end of that barrel.  You'll have to get the recoil and gas systems working correctly before you can make that determination.  Don't spend the money on the brake right now, as it needs spent in other areas first.  Hope that makes sense.

[98Z5V]

2 hours ago, 98Z5V said:

Next, where does your gas tube end, inside the upper receiver?  Is should end directly in the center of the cam pin cutout in the upper, which is that half-moon looking cutout space in the upper, the space needed for the cam pin to rotate and lock the bolt in the barrel when cycling.

See if you can get a pic of that put up - a pic straight down into the upper receiver, BCG removed.  Straight down over the end of the gas tube.

Don't make your Armalite Order yet - you'll probably need to add an AR-10 rifle gas tube to the order... 

Here's exactly what I'm talking about - it should look exactly like this, right here - this is what proper gas tube length looks like, which is direct reference on proper drilling of the (common) gas port positions, to work with common gas tube lengths:

[MDWeaponry]

3 hours ago, 98Z5V said:

You shooting a carbine recoil system or rifle recoil system?  What kind of buttstock is on there?  Fixed buttstock like an A1 or A2, or is it a collapsible stock?

Disregard - I went back through the post and saw the pics.

So, yes, you need the Armalite AR-10 Carbine Recoil System - this one is cheaper than possibly attempting to piece together everything:

Armalite AR10REKIT01 is the part number.

https://www.armalite.com/product/ar10rekit01-6-position-receiver-extension-kit/

Now, this is especially important, right here.  For PSA to get a 20" rifle gas system barrel to even perform and cycle with that superlight recoil system that they put in it, the HAD to make that gas port in the barrel undersized.  You need to take that gas block off the barrel, and verify the gas port diameter - I'll be you need to drill that port UP in diameter, because it's gonna be too small.

Next, where does your gas tube end, inside the upper receiver?  Is should end directly in the center of the cam pin cutout in the upper, which is that half-moon looking cutout space in the upper, the space needed for the cam pin to rotate and lock the bolt in the barrel when cycling.

See if you can get a pic of that put up - a pic straight down into the upper receiver, BCG removed.  Straight down over the end of the gas tube.

Don't make your Armalite Order yet - you'll probably need to add an AR-10 rifle gas tube to the order... 

 

Okay so it looks like I’m gonna need that new tube as well. I will be getting a new barrel likely from criterion so I may go that route rather then drilling this one unless it’s pretty simple, I just wouldn’t want to screw it up.

also I’m getting ejector smear/stamping on the cases, some mild cratering of the primers on good ammo, and pretty bad cratering on cheap primers and I even have a couple pierced primers. Not sure if it’s the gun or if it was the cheap ammo that is responsible.

 

[98Z5V]

Those ejector smears are leaving some pretty serious edges on them.  You wouldn't even be able to put that used brass into a reloading die, unless you filed that stuff down first - it wouldn't go into a reloading shell holder all the way.  Been through that.  That's from a square ejector face, and the bolt trying to unlock too soon (both of those things).  Bolt trying to unlock too soon is a "timing" issue.  That can be a recoil system that's too light, or a gas system that's too strong - or both.  Or, third option - some SERIOUSLY hot loads...   Recoil systems and gas systems absolutely must be balanced, to function properly.

These aren't race guns.  Race guns have their place, with ultralight parts, small gas ports, adjustable gas blocks, etc.  Race guns also run ONE load through them, for competition use, and it's either a tailored load for that specific gun, or all that gun's ultralight parts are made for a specific factory load... 

I just talked about those kinds of ejector smears, recently, and I've been through it myself, with some .338 Lapua Magnum ammo...

 

Edited August 27, 2019 by 98Z5V

[98Z5V]

51 minutes ago, MDWeaponry said:

I will be getting a new barrel likely from criterion

Look at Ballistic Advantage as well. I have one .308 Win Criterion barrel, and it's badass, but it was from 2010.  Most of my stuff recently has been BA, with a few Faxon Match barrels mixed in.  All of my BA barrels have exceeded my expectations.  Hit the banner for then at the top of every page.  I'm not advertising for them, but last Jan I had someone from BA tell me about a new barrel they were making, and I called the shop right away  - the poor lady that answered the phone had no idea what I was talking about, and couldn't find the barrel.  After a 10-minute hold on the phone, she came back on, stated they weren't even in full production, definitely not announced (and they had no pricing on them), but that the person she talked to said I could have one if I wanted it.  I just gave her credit card info...   It arrived 4 days WITH a pinned gas block and gas tube, at 40% lower than they "announced" the barrel at more than a month later...  I pulled that barrel for about $150 shipped, with the pinned gas block and gas tube.  This is the barrel:

https://ballisticadvantage.com/16-inch-65-grendel-spr-mid-ss-premium-barrel.html

With less than 30 rounds through it total, I put it out to 500 yards - zero cleaning, zero "barrel break-in BS" - not even a patch through the barrel during firing (I did bore-snake it before I installed it). I just shot it, straight.  At 500 yards, it layed in a group that was 5" high and 7" wide.

Based in what I've experienced from Ballistic Advantage, they will be my go-to barrel from the get-go, on any build.  That was a brand new barrel that did that, "unseasoned" and whatever.  It definitely wasn't "broken in" yet...  

Here's the thread on the gun:

 

Here's the thread on the initial range report - there's lots of other chaos in this thread, too...  

With the ungodly customer service I've had from them, the incredible hookup on that brand new production barrel, pre-production, and the results I've had from them - they will always be my go-to first, for a barrel.  If they don't make it or can't/won't make it, but Faxon does - I'll jump right on that Faxon and not even think about it twice.  Those are my companies, and they've proven it to me.  My 12.5" Grendel barrel is a Faxon - and the performance from that thing blows my mind...  My $0.02...

Edited August 27, 2019 by 98Z5V

[MDWeaponry]

So basically the consensus on the ejector smears would be to fix my recoil system and lightly chamfer/bezel the ejector pin faceand go from there? 

That’s a nice group at 500 yards! I’ll check out your threads here shortly. 

I was actually looking at ballistic advantages but then I started seeing horror stories of ruptured cases and some other stuff so I started looking elsewhere, maybe I need to put some more thought into it and reconsider ballistic advantage. How does the ballistic advantage compare to the faxon and criterion accuracy wise? I only have the funds to do it once but I could spring for something a bit more costly the first time if it will cut the group size down a good bit.

[98Z5V]

41 minutes ago, MDWeaponry said:

So basically the consensus on the ejector smears would be to fix my recoil system and lightly chamfer/bezel the ejector pin faceand go from there? 

That’s a nice group at 500 yards! I’ll check out your threads here shortly. 

I was actually looking at ballistic advantages but then I started seeing horror stories of ruptured cases and some other stuff so I started looking elsewhere, maybe I need to put some more thought into it and reconsider ballistic advantage. How does the ballistic advantage compare to the faxon and criterion accuracy wise? I only have the funds to do it once but I could spring for something a bit more costly the first time if it will cut the group size down a good bit.

I'm responding in colors...  Your color I highlighted, my colored answer...

Show a pic of that ejector face, first.  It's square, I guarantee that.  Something caused that, the the square ejector was the reason, but there were alot of other contributing factors that made that square-faced ejector eat that brass up like that - that's as bad as I've seen, on my own stuff before, and I had to file that shiit out of the brass in order to use it again.  You do need to address the recoil system, and that will make you address the shortcomings in the gas system, afterwards.  Building a fully functional gun, that doesn't kick the shiit out of you (a proper recoil system for a .308AR, with a balanced gas system for a .308 AR), is the number one goal.  After that, and after shooting it - you move to smaller things that suit your preference - like brakes and what-not. If the recoil system is proper, and handles the weight/mass of a .308AR BCG and the power of a .308 Win cartridge cycling, and the gas system is balanced to that - then a .308AR is one soft-shooting rifle.  Any .308 Win bolt gun that you pick up will impart more felt recoil on you than any AR-platform should...

That pic of that gun above is the best, recent accuracy that I can state about Ballistic Advantage - can't even say enough about it.  Brand new barrel, 16" 6.5 Grendel, going so-damn-near MOA at 500 yards - right out of the gate.  Not even a seasoned or broken in barrel. They make great barrels, or I wouldn't have done that.  All that lateral dispersion was probably me, too, with the 7" wide on that group.  That group you saw had 12 rounds through a brand new barrel to zero a scope.  Then it had 10 rounds through it to confirm zero - all at 100 yards.  It then went straight to 500 yards.

I'll be testing a new caliber (to me), on a new Ballistic Advantage barrel, very soon. Results will certainly be posted. I went with the BA barrel based on my experience with them so far. They've never let me down.

I've never heard anything like that about BA barrels.  Links to what you're talking about, in reference to that, would be awesome.  I've never, ever had issues like that from any of the BA barrels that I have.  Not even close.

One Criterion barrel, a match barrel from Fulton Armory, 18.5" .308 Win Barrel, 1:10" twist, Fulton's "Hybrid Chamber" - it's a Match Grade barrel from Fulton Armory, made by Criterion from 2010 .  It's just as badass as the BA "Premium Series" and Faxon "Match" barrels that I have in .308 Win (and alot more of the BA Premium barrels I have in other calibers).  They're all good.  There's a reason I've gone with the BA Premium barrels recently, though - I have enough of them to say that they do not let me down, in the least, any caliber, and always surprise me with what they're capable of.  Had I had more Criterions?  yeah, maybe.  More Faxons?  I'll always go to Faxon, if they have a profile or combo that BA doesn't - and I want it.  The Criterion is great - but I don't look at them first anymore, with the quality that BA and Faxon put out.  I have no reason to. 

Testing groups on paper at 100 yards, looking for something that's super tiny with a 3-rd or 5-rd group...  I don't believe that's "accuracy" per se.  Too many factors.  Get that thing out at some distance, and see what it does.  Get some wind involved, and some distance.  500 is my minimum distance, after zeroing at 100 yards - I almost always set up scoped rifles for 100 yard zero, with few exceptions.   See what that thing does at distance, IMHO.  That will tell you more about accuracy than anything else.  This brand new 16" Grendel barrel from BA just put down 12 rounds to re-zero a scope that I took off another rifle to shoot the basic build, then I put another 10 rounds in a mouth-sized space on an ISPC plate - then I took it straight to 500 yards.  5" x 7" group. I'll take that all day long, from a brand new barrel.  That tells more about the barrel than anything else.  They definitely don't make bad barrels, or that wouldn't have happened.  Consider it with confidence.  I have no doubts, anymore.   

Edited August 27, 2019 by 98Z5V

[MDWeaponry]

So I got a chance to shoot it again this week. Took it to 500 yards. Now this is my first time ever shooting 500 yards or even anything over 200 but I’m actually very surprised with the accuracy. I did notice a tendency for the shots to rise as the barrel heated. 

All shots marked .308 were out of the pa-10. The bottom two unmarked shots were mine as well. 

This is a 10 inch plate. Not bad for my first time at that distance.

[MDWeaponry]

So I took it out again today. 750 yards verified with rangefinder. I didn’t have any match ammo, so I decided to just have some fun and see what happens after my family/friends shot their rifles. 7 shots out of 20 on target using aguilla .308 and military surplus 7.62x51. 10 of each. Wind was heavy to the right so I it was about 2.5 moa of correction for wind drift. 7th shot isn’t circled but is located bottom right of target. This is a 10 inch steel plate. Considering it’s a 500 dollar rifle shooting the cheapest ammo there is I think I got a hummer. This is my second time shooting long distance. First time was my last post. I’d say I’m doing pretty decent for a newbie, and the rifles doing really well especially considering the cost. This is still the factory rifle setup as well, I haven’t changed the buffer assembly, trigger, or anything yet.

[Armed Eye Doc]

Nice shooting regardless of the rifle. 

[98Z5V]

That's a pretty damn great job, with that ammo, at 750 yards - well done.   It's tough to get a 150-ish grain projectile out that far, with no wind, let along 2.5 MOA wind hold.  Well done.

[Cliff R]

I'm up to 4 PA-10 builds at this point with zero function issues with any of them. 

Among the first was the rifle pictured below.  I didn't try to run any of them with the 6 position stock and buffer system PA supplied, all of them got A2 stocks and the buffer/spring shown.

I did all this WAY before finding this sight, so pretty much it's like the blind squirrel who found a nut.  I've ran half a dozen factory and Military loads thru the one in the pic, which is my personal weapon and taken out West every Fall Elk hunting.  It's a 14.7" barrel (released only once by PA far as I know) as I'm been looking for them to do that again and to date haven't seen any made available.

I settled on 175 grain Barnes bullets back by 42 grains of Varget (going from memory here) or something close to that.  I throws the brass very consistently and no witness marks showing that it needs any shimming or other buffer system or gas feed hole modifications.

As far as accuracy goes it's better it's very acceptable for this type of weapon.   100 yard groups will go under an 1" and 300 yard groups fired like I'm hunting with it hover around 3-5" without much effort from me.  It doesn't do as well with a some of the commercial ammo, sort of liked Winchester 150 grain soft points but not very fond of some Fusion loads I ran thru it.  It actually shot just a tad better with some old 150 grain Sierra bullets I had left over from reloading for my 30-06 back in the 80's-90's pushed by some pretty old IMR-4320 in new Winchester cases, but I settled on the heavier Barnes bullets since it's pretty much a dedicated out West hunting rifle.

Just my experience with this platform.  I'm not completely sure where I sourced the buffer and buffer spring for the A2 stock conversion but I'll look into that a little further and see if I can find out what they are and where I sourced them from?.........Cliff

 

[98Z5V]

Won't matter much where they came from, Cliff - .308AR rifle buffers (DPMS-based and Armalite-based) are 5.200" long and weigh 5.4oz.    The rifle receiver extension is 9 11/16" internal depth - it's the same extension used in AR15 rifle-stocked guns.   Companies don't mess that up too often, but we've seen one or two here that didn't hit those numbers.  It's an oddity, not common. 

[Cliff R]

Good to know.  I found a receipt listing them as DPMS LR-308 Rifle Buffer part number 308-BS-11 and DPMS LR-308 Buffer Spring 308-BS-10B.  Also found this photo from a range day.  I have a photo someplace at 300 yards as well and will put it up here if I can locate it........