This is actually a Palmetto PA-10, but the issue seems to be generic to the Stoner design, so posting here since I suspect this sub-forum has more views.

Palmetto PA-10.

I removed the barrel nut three times as I was doing inspections and other adjustments.

Each time, the barrel nut came off the gun with a lot of binding, and damage to the barrel nut.

This pic shows what the barrel nut looked like when I removed for the third time. On each removal, there were bits of aluminum from the barrel nut left behind in the barrel nut. This third time seems the worst.



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Next pic shows the barrel mounted in the receiver. Is this index-pin standing-proud too far, and contacting the barrel nut, and shearing the point off the threads of the nut?



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Here is a pic of the barrel mounted in the receiver after the third removal of the barrel nut. Notice that the threads on the receiver are completely undamaged.

I should also mention that I separately mounted a replacement barrel nut, JL Billet part #JLB-308-BN16, and I experienced the same sort of binding and damage to the nut.

All the pics you see above however are the Palmetto barrel nut.

I'm pretty sure its the index-pin standing proud that is causing the problem. But, I'm fairly new to wrenching on AR-type guns. Figured I would make inquiry before breaking out the dremel, and shortening the index-pin.

The barrel nut is aluminum correct? And yeah, the indexing pin is definitely sitting to high which is causing this problem.

I'd send id back to PSA with a note about the pin.

I wouldn't trust that barrel nut to hold on to a .22 LR cal receiver. And yes, as others have said, pin is too long.

Thanks for the observation about the pin.

I'm not "sending back" anything to PSA. Those guys talk a good talk in the forums about customer service. If people are really patient or really outspoken, PSA even sometimes gets stuff right when customers have an issue after the purchase. Send out a replacement. It's easier than admitting that they sent out a whole pallet with the same issue. When it comes to the fine points of assembly, let's be real, they're just slapping the stuff together and sending it.

Thanks for helping me confirm that the parts are not playing nicely with each other, and its not just me not getting it on the mechanical side.

Index pin above the thread minor diameter is going to wreck the nut, for sure.

It's an inspection point for every upper I build.

If it were me, I'd shave down the pin, get a new nut, and keep rolling. Don't forget to dress the top of the shaved pin to remove any burrs.

...and in direct answer regarding the material of the barrel nut, yes... it is aluminum.

Someone asked:

I beat on the pin and down she went.

I have concerns that she'll just migrate back up.

Can I yank it out and then fill the hole with JB Weld and beat it back in to hope it will stay put?

The theory that the pin is moving around seems to be supported by the fact that the worst damage to the barrel nut didn't occur until the THIRD time I removed the nut.

I'd run the pin down until it touched the barrel but you can still remove it [barrel] measure the depth, remove the pin, red loctite on it and drive it down until you get your depth, check barrel fit and removal, remove the barrel, clean the threads, barrel and anything else that got loctite on it, let it sit for a day or two to set well and then install barrel and nut, make sure you have no loctite anywhere on threads of nut or threads.

I just tried yanking the pin out with a pair of needle-nose vise grips.

She aint coming out that way. BTW, that pin is hard metal.
Put a divot in the tip of the cheap vise trip pliers.

So, banged it back down as deep as I could get it.
Probably won't chew up the barrel nut during install.
Fully expect it to migrate back out and chew the nut some more on next removal.

Glad you got it squared away but I doubt if it backs out any if it's that tight.

Just out of curiosity, why are you having to remove your barrel nut so often?

Tap the pin back down, install a new barrel nut and you really shouldn't need to worry about it again until the barrel is shot out (unless you're constantly switching upper receivers or rails).

Three times isn't really that often.

But since you asked:

I expect an AR15 to hold the 10 ring on a service rifle target. This one always walks shots vertically with no real rhyme or reason. It will shoot in one location for a while, then next thing you know, its out the bottom in the 8 ring. Then back into center. Then out the top in the 8 ring. It doesn't just walk to one spot and stay there while the barrel is hot. I've been shooting service rifle competitively for about a quarter of a century. I hold pretty damn hard - especially prone. I don't shoot 8's... or if I do, I call the shot there because I know it when I do it. Now that we can shoot scopes on service rifle, there are no longer any mystery corner-shots or such. I've tried a completely different scope and mount. Same thing good 10-ring windage, random 8-ring wandering for elevation.

So, I'm pretty well certain its the gun, and not me, or the scope.

First time I took it apart was just to inspect. See what's under there. Looked OK, so I put it back together, and made sure the barrel nut was good and tight.

Still shooting 8's.

Second time, I actually removed the barrel from the receiver to look at things more closely.

Still shooting 8's.
Someone suggested running a lapping tool on the receiver face (although it didn't show any evidence of needing lapping)
Got a lapping tool

Third time, pulled the barrel and the nose of the lapping tool was so damn tight trying to go into the receiver, that the only way it was going to go in would be if I bashed it in with a heavy hammer. I decided that would be risking much, and for very uncertain reward.

So, here we are.

I'm going to replace the entire Palmetto bolt/carrier group with a new ToolCraft BCG. Something else is going on with this gun that I've never seen before. The bolt is getting eaten-up by the receiver extension. At 700 rounds the bolt lugs all look like hell. I can't say I know why ate-up locking lugs would only throw elevation shots. But, I'm hoping that simply replacing the BCG will make a positive difference.

I've got a whole other big thread going about this gun in the AR-10 subforum.
https://www.ar15.com/forums/t_3_121/738374_Palmetto-PA-10-rifle-length-upper-ejection-issues-rough-workmanship-accuracy-improvements.html

https://www.ar15.com/forums/t_3_121/738374_Palmetto-PA-10-rifle-length-upper-ejection-issues-rough-workmanship-accuracy-improvements.html

Here's what the Palmetto bolt looks like after 700 rounds.

While I had the barrel out of the receiver this time, I also used a pointy dremel bit with an abrasive stone-tip (just the bit by itself by hand - not even mounted in the rotary tool) to try to de-burr the lugs on the barrel extension where the lugs have been chewing on the Palmetto bolt.

Also you could peen it.

My pa10 is starting to show signs of the bolt getting beat up too. I was told it may be out of time.

Btw, how can a man get into doing those nra shooting matches? I'm in northern nc.

The "out of time" suggestion is always on the table whenever there is an issue of bolts that aren't locking right. Very hard to pin that down from my perspective.

Highpower rifle competition for service rifle and match rifle is a really big deal in northern NC. Butner/Creedmoor is the place.
Club is "North State Shooting Club" - shoots at the National Guard range (out to 1000 yards) at Butner.
The season is mostly March - October.
See http://www.northstateshootingclub.com/pdfs/2020/2020matchschedule.pdf

I will be there for the "CMP Cup" week for sure.
See http://thecmp.org/competitions/cmp-travel-games/eastern-games/
Electronic targets are great.

Otherwise, Butner range uses targets that are driven by (go up and down for scoring) electric motors. Which helps on the fatigue issue on a long hot day.

Got it all put back together now.

Gave the bore the bizniss with some JB while I had it off the rifle.

Torqued the original nut (the ate-up one) to 55 foot pounds.

Installed the new ToolCraft bolt/carrier group. Small-diameter firing pin, double ejectors. Less and less of this rifle is still Palmetto. Sure hope that Palmetto barrel extension doesn't eat up that new bolt. Headspace measured out at 1.634". That's about where it was at with the Palmetto bolt. I know that's a little on the long side (Forster No-Go gage is 1.634"). I could tell the 1.634 gage closed tight. Should have known better than to try to get it to swallow the 1.635" gage. Man, that thing stuck in there like a sumbitch at partial batttery. Mortar/pogo was no-go. Had lay the big rubber mallet against the ear of the charging handle and wail on the rubber mallet with a four-pound sledge to get it to open up. I gotta stop doing that. But I just HAD TO KNOW. Now I know what I knew before I pulled that stunt. It aint gonna swallow a 1.635.

So yeah, 1.630 is the "perfect" headspace for .308. I doubt 0.004" is the cause of the up-down stringing. But, who really knows.

Still need to put the scope and sling back on. I'll do that, and shoot a pic in the morning when the light in the room is a little better.

Taking it to the range in a couple of days. Sure hope it at least cycles with the new bolt.

Tagged, a lot of good info in this thread.  Ive got 400rds on my bolt and it's starting to show wear signs on the back side of the  bolt.

Ive since then changed to a rifle buffer and spring and got a seekins adjustable block.  Maybe that problem will go away.  I'm getting real tight groups with my hand loads.

I hope you can correct the wear issues on the bolt as I'm watching to see what the cause is.

Below is the Dremel bit I used to de-burr the locking lugs on my barrel extension.

I used only my fingers to "drive" the bit. I did not install the bit actually in the motorized rotary tool.

I spent about 45 minutes, while watching TV, going over the radius-edge of each lug of the barrel extension.

Prior to the de-burring job, the lugs on the barrel extension would "grab" bits of Q-Tip cotton when cleaning the lugs. Now, the lugs do not grab any cotton.

I went back to the old thread and I'm re-posting the pic of the lugs of the barrel extension as it appeared some months BEFORE last night's adjustment with the dremel bit.

Link

My bolt looks ok at 400rds, there is one nick On the front you can see to the left, the rest are perfect.

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The back is a different story,  there are multiple wear spots on them that i can't get a good picture of.  Let me see if i can get some.

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At this rd count this amount of wear is unacceptable. I already had a smith find that the no-go closes on the rifle which is also unacceptable. I feel at 700+ my bolt may look like yours. Unless the heavy buffer,  and adjustable block have corrected the issue. Range Time will tell.

Use a fresh barrel nut, torque it, and forget it.

Buffer kit

buffer is 5.6 oz

And a seekins gas block. 3.5 turns out. I must say,  I've only fired a few rds after the stock change.  Most of the damage occured with the factory set up.

And that may be why these bolts are prematurely wearing.

Edit:  What i meant by this was the factory set up causing the issue. Lol...

Only a hundred or two rounds on mine and the bolt only shows a little normal finish wear. No problem with cycling changed the stock to full rifle 308 rifle buffer on a mid length barrel to get a little less recoil but pretty happy with the gun so far. Carrier dinging the bottom receiver buffer threads just a little but the rails are not cut back to stop that like some carriers are.

Did you change to rifle stock at first? Or is the 200rds on the oem stock. Mine had zero issues with carrier over travel.

I've used the Magpul UBR stock on my gun from the very beginning.

DPMS LR-308 carbine buffer spring.

KAK 5.3 ounce carbine buffer.

Now that there is a "Generation 3" PA-10, it bears mention that my gun is built on the Generation 2 version.

I have read that the Generation 3 furnishes a Toolcraft bolt.

I have no idea where PSA sourced their BCG parts for the Generation 2. With mine the extractor was a complete disaster of fail-to-eject. I replaced the extractor on the Generation 2 bolt with an extractor assembly from Fulton Armory.  Once I made that swap, all extraction problems ceased. I also added a rifle-length gas tube for the Fulton "Titan" line. This gave me more protrusion of the gas tube into the receiver. Since I made several of the changes at once to address failure-to-extract, I really dont' know whether replacing only the extractor would have made the difference. I replaced the extractor and the gas tube at the same time.

Note that the original PSA gas tube protrudes into the receiver (and therefore also into the gas key) much less than the Fulton gas tube.

Original PSA gas tube:



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Fulton "Titan" rifle-length gas tube:



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Comparison of Palmetto and Fulton extractors.
Palmetto used two springs (and no insert) and a donut - weak tension and not very "grippy" claw
Fulton uses one spring with polymer insert and a donut - very good  tension and mucy more "grippy" claw
(note that the ToolCraft bolt I will be using tomorrow has a fairly stiff spring, and a donut, but no polymer insert - not pictured here)

Is it possible that the longer gas tube is just long enough to prevent the BCG from fully locking up in the receiver extension, leading to the wear you encountered on the rear of the lugs? Running it with the supplied gas tube after the ejector swap would have been a useful analysis step.

There is no evidence that the mouth of the gas tube is impinging the gas key. That carrier moves with enough energy to darn near chop your finger off. Certainly after so many hundred rounds, the mouth would show damage if fire/aft impact were occurring.

Heading to the range with it in an hour.

By filling the gas key with more tube, you are reducing the gas key volume, which causes the pressure to stay higher and accelerate the BCG to a faster speed than the shorter tube.. Further, the tube staying engaged in the key for that longer distance causes the pressure to be maintained longer than with the shorter tube, keeping the BCG speed up for longer.

I really would recommend giving the original gas tube a shot. If it doesn't run then go back to what you had. If it does run and you see the other issues resolved then it's a win. You should be able to swap the gas tube in the field with just a few hand tools.

Range report.

TLDR version - Accuracy still sucks. Rifle is junk.

I fired prone all shots today.
Beautiful conditions. Light overcast, which is perfect lighting conditions for this type of shooting.

I fired at four targets. I'll post pics of three of the targets below. No point in posting the target I used to re-establish zero, and on which I was cranking sight knobs. I had to come down about two minutes from what I thought was my correct zero.

You may care to know that the targets for the 13-shot and 10-shot groups are correct reduced targets for 200 yards to simulate the 600 yard NRA highpower rifle target. The Shoot-N-C centers very closely approximate the correct location of the scoring rings for that target. The aiming-black area of each target is approximately 13-inch diameter.

All firing from prone, sling-supported position.

I normally like to test accuracy by shooting 10-shot groups.

First target has 13 shots because I concluded that my zero was actually off by a couple scope clicks (1/10 mil - same as 1/3 MOA per click). Group is pretty much all over the place. I called one shot low, and two shots left. I called one shot "loose" - no call really - but you know when you shoot one of those that it could land anywhere - which it did out to the right in the 7 ring. Otherwise, all shots broke solid center. I shot the extra three shots in this group because it was already such a mess, I wanted to see where two clicks left would put me.

Second target is a 5-shot group. I fired this on a different bank of targets,a and also after making the aforesaid two-click adjustment. This actually gave me some hope that maybe that first mess of a target was just me. I could live with this kind of accuracy.

Third target is 10 shots. This target was right next to the nice 5-shot target, and was fired immediatly after that 5-shot target. Again, we've got shots pretty much all over the place. First two shots were high 8's. Each called a good center shot. After that, the hits just danced around wherever. That, despite me calling the shots good. I definitely had my position and trigger control established by the time I was on this third target.

The gun ran fine with the new ToolCraft BCG. The bolt seems to have weathered the day without being chewed-up like the Palmetto bolt.

But, accuracy just suck.

Only three things could be happening here.
1. Maybe the ammo is terrible - I doubt that. I've always said that if you shoot a good bullet through a good barrel, you will get good results shooting at service rifle targets. Things like choice of casing, or primer, or powder tend to matter very little compared to the major factors of "good bullet and good barrel."
2. Maybe I just can't shoot this rifle, even though its a slightly large version of the same rifle which I can consistently shoot high master scores (97%+) on a 200-yard range. So I doubt its the shooter.
3. Maybe its something about the rifle - who knows what. I suspect its simply the barrel. Like I said, "A good bullet through a good barrel..."

At this point, I'm going with "bad barrel" as the major reason this rifle can barely hold the 8-ring on an NRA highpower rifle prone target.

The cost of a replacement barrel is really not the issue at this point. Unfortunately, I live in goddamfugkingVirginia, and this gun is about to be BANNED by the asswipes who just took over our government.

I'm not gonna spend money on a new barrel I can't legally shoot.

The new laws will go into effect July 1. I'll decide what to do about this gun sometime between now and then.

TARGET 1


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TARGET 2


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TARGET 3

Well,  i guess it's pointless since your minds made up.... or i hope not but the local governments helped make it up for you,  burr that's a different story.   But i disagree,  my rifle was getting 2" groups with smk 168 fgmm cartridges.  I switched to hornady. And worked up a 165gr. sst with varget and got 5 shot groups like this at 100yds.  Are you just using a basic plicking load?

Attached File


This was the same target with a few tenths a grain difference before setting the seating depth.

I believe you can get that barrel to shoot with a little load development.
Attached File

I wouldn’t describe any load built on a 168SMK A “plinking load.”

What i mean is... for instance my brother wanted a few hundred loads just for shooting.  So i loaded him some similar to the gmm load at 41.5 gr, on a 168gr smk just to hit the range one afternoon.

Maybe give the eld a try,  you may get better results.  There's a lot of good different bullets other than the smk.

I hear ya

But I’m not optimistic. Considering the origin of this barrel, and the low price paid, the adage, “You get what you pay for” looms on this effort.

I’ve got some Federal Gold Medal, and some Lake City M852. Even have a box of “white box” long-range that was issued to the Navy team shortly before the Navy quit most support for rifle teams. Might as well try it as medicine on a patient that badly needs a cure.

Weather for the range supposed to be very nice today. Even if the Palmetto gun still sucks, it will be a fine day to be outdoors.

I have an spr build that shot like that with a colt govt barrel

once i upgraded the set up to a LaRue barrel and a vltor upper receiver, it became much more capable of moa groups

Yeah,  you'r right.  I plan on a criterion barrel in the future,  and that sucks but it's the truth the barrels just aren't that good. Any time at the range is a good day.

Yeah, it’s probably a dowel pin. Those are pretty hard.

All those alignment pins should be a press fit in the extension. A thou of press is pretty difficult to overcome on something that small. If it seated, it’s going to stay put.

Nothing's been passed or signed yet, load up everybody's inboxes. Sux we're stuck with so much blue, but there's too many moderate districts for that crap to pass unimpeded, no matter how much "Coonman" wants to play it up.

On your situation, I'd try a different powder, I've had forgiving powder ranges showing good accuracy with RE-15 from 150-168gr bullets.  Tac just might not be your solution for this rifle.

I've shot IMR-4895, Varget, and TAC in this rifle.

Same behavior with each.

I happen to have a lot of ammo loaded with TAC right now, so that's why I'm shooting it in the recent tests.

I've shot various flavors of surplus ammunition though it too. Mostly Santa Barbara. Same deal. Big groups. Wandering elevation mostly the problem. But not adequate for windage either.

Little range report.

I shot the PA-10 with Federal Gold Medal 168. I’d say it shot the FGM a little bit better than my TAC 41.1 / 168SMK.
But not by much. Definitely not enough to commend the Palmetto barrel. I’ll post a couple of those targets shortly.

But first, I want to show y’all something about that TAC handload of mine fired from a different rifle. Again, all firing at 200 yards, prone, sling-support only.

DPMS LR-308-T, unmodified except Geissele trigger and the UBR buttstock. Service rifle sling not shown in this pic.



This pic shows the 10-shot target. I bracketed the actual target with a paper target that is the correct 600-yard-reduced-for-200, and the Shoot-N-C target that has appeared in some of the previous target pics I’ve posted.

This is the kind of accuracy to which I’m accustomed, and which I require of any rifle I will use in competition. The two lowest shots, were called low when fired. No crazy off-call shots like the PA-10 routinely sends. The TAC load wasn’t “developed” for that rifle unless roughly matching 41.5 IMR4895 velocity constitutes “development.”



Some folks have commented that I should look at the load. “Develop” a load that the gun likes. Sometimes it really is the load. I get that concept.

Can we agree that sometimes the barrel (or something else with the gun) is the root of the problem, and not the ammunition? I truly believe it’s THE GUN in the case of the PA-10.

Here are the two targets I fired today with the PA-10, using Federal Gold Medal ammo with 168-grain bullet