PSA PA-10 chamber out of spec

[Metal god]

Originally Posted by Gary at PSA

We use PTG gauges to head space all of our bolts and barrels. Yes, our techs did check headspace before installation.

I just received the PTG NoGo gauge from Midway USA 2 day air . The upper FAILED the gauge .

Needless to say , Its going back for refund .

[stagpanther]

This is going to be interesting to see their response.

[Metal god]

This is going to be interesting to see their response.

Maybe not , There was a second email I received from them answering my question of can I still return the upper for a refund which is in post #48 ( not the response just the question ) . They said yes because it was still with in the 30 period . Either way I sent an email asking for the refund and shipping label but that was this afternoon ( end of there day ) so I likely wont get a response until Monday at best .

My guess is they only test a Field gauge and call it good . Which I'm not comfortable with . I considered keeping it so I had everything I needed ( gas block , rail , upper carrier ) if I wanted to buy a new barrel but just decided to be done with it .

[stagpanther]

I just noticed from your picture that you left the ejector and extractor on your bolt when you tested with the shim--you do know that you should remove them when using the gauges?

[Metal god]

I just noticed from your picture that you left the ejector and extractor on your bolt when you tested with the shim--you do know that you should remove them when using the gauges?

Yep and I did address that in the other thread . In a nut shell I did not want to disassemble the bolt in case it had to be returned for repair . I do not have the proper tools to do so and would surely have marked up the bolt . I didn't want anything I may have done to allow them to void my warranty . Not to different then only firing factory ammo . Regardless having the extractor and ejector installed in the bolt does nothing to hinder the results of the bolt closing fully on a NoGo gauge . The reason you want them removed it because they may cause the bolt NOT to close on the gauge resulting in a false reading . In this case the bolt closed completely on both brand NoGo gauges and it should never close on those . There is nothing that having the extractor or ejector still in the bolt would cause the bolt to close on both brand NoGo gauges that they other wise would not have . I'm OK with how I did it and the results I believe it shows .

[stagpanther]

What is the actual length of your no-go gauge? Have you actually charged the carrier and let it fly on the gauge?

[44 AMP]

Have you actually charged the carrier and let it fly on the gauge?

Why would he? That's not the way to use a headspace gauge. In fact, this is the first time I have ever heard anyone suggest doing that.

Letting the bolt "fly" forward under spring pressure risks damaging the rifle, and the gauge, AND giving a false reading.

Metal god, IF your gauge and their gauge are the same, and they get a pass and you get a fail on the same barrel, logic says someone isn't doing something right.

You sound like you are doing things right, we expect and assume a manufacturer does its tests right, but with opposite results, you can't both be right.

Just for personal satisfaction, I would have a competent 3rd party do the check as well. With their gauges, and with yours, if possible.

If I'm doing it wrong, and somebody shows me I'm doing it wrong. I say, "dang! I did not know that..." and learn to do it right. But if I'm a company, selling products to the public, and I believe my people are doing it right, and someone isn't, I need to know that, so I can fix it.

Simplest would be just sending it back and getting something else or your money back and be done with it.

Best would be finding out who is in error and fixing it.

Good Luck

[Metal god]

Have you actually charged the carrier and let it fly on the gauge?

Why would he ?

The question was asked likely for the same reason given . If I were doing that I would likely be damaging the bolt and do it enough I would likely start getting false readings .

I don’t let the BCG fly home on any of the gauges . I remove the upper from the lower , place the gauge in the chamber and slowly push the carrier foward until it stops then from the butt of the carrier I try the force it closed with the palm of my hand .

I once used a light rubber malet to tap it closed but it turns out that’s not needed . The bolt is closing on the NoGo gauges with firm pressure with my palm on butt of the carrier .

I have not measured the gauges but they operate correctly with fully assembled bolts on 3 other 308 rifles and the fact it fails two different brand gauges would seem reasonable to me the gauges are not the issue .

Metal god, IF your gauge and their gauge are the same, and they get a pass and you get a fail on the same barrel, logic says someone isn't doing something right.

I agree however Gary has not said that it passed any specific gauge . Meaning he has not said "we use PTG gauges and it passed our NoGo gauge" He only states they use PTG gauges and it passed . I know one can think that's the same thing but it's not . I still contend and this is just my opinion . It only passes there field gauge and not there NoGo or maybe they don't even test a NoGo knowing a field gauge pass is all that is really needed .

[stagpanther]

Why would he? That's not the way to use a headspace gauge. In fact, this is the first time I have ever heard anyone suggest doing that.

I didn't suggest he do that--I asked the question specifically because he was using the gauge with the extractor and ejector--as well as a shim--still attached to the bolt face. The gauges will not work properly, nor were they ever intended to--with the extractor and ejector still integral to the bolt. Because of the inherent resistance to the extractor people sometimes (incorrectly) force the bolt--including dropping the charged carrier.

This thread has crossed into the absurd zone--I'm out.

[Metal god]

This thread has crossed into the absurd zone--I'm out.

Not sure where you get absurd but maybe you don't have many conversations with people . If we were all face to face this "conversation would be over in about 20 min but because it's on line through the written word where people can talk on the own time . It's seems to drag on and be incomplete at times .

All I've been doing is having a conversation with" friends " in between responses from the manufacture . That's how I view these forums . You clearly view them differently .

However I understand how I'm doing it wrong , can you explain how a bolt will close on a NoGo gauge the way I'm doing it and not close on that same chamber when done "correctly" ? I mean does the chamber grow or the gauge get smaller the way I'm doing it ? The gauges eject freely with no binding of the bolt lugs just as if I were ejecting a case . If I had to mortar the gauges out then maybe my way is giving me false readings and If I did have to mortar them out I'd likely be ok with the headspace .

I've already explained why the bolt needs to be stripped the way I understand it . Maybe you can explain how you believe a bolt can close and freely eject on a NoGo gauge that is properly spec'd regardless of how you test it ? .

[zeke]

https://www.youtube.com/watch?v=VvI97DVQS70

https://www.youtube.com/watch?v=-LgBEIzBQTY

https://www.youtube.com/watch?v=_jIqlIdUCco

https://www.forsterproducts.com/pdf/...structions.pdf

It would not appear that a no-go gage relates to max sammi chamber dimension. It would also appear that forcing a gage into place may wear the gage surface/bolt/chamber contact surface. Am not a gunsmith, but the included links are from manufacturers, including PSA.

[Metal god]

You all have convinced me , I’m taking it to a gunsmith today .

[ed308]

I always thought if the bolt closes on the NOGO gauge, it doesn't necessarily mean the rifle is unsafe. But does indicates you need to check with the Field gauge to determine is the firearm is safe to shoot. The Field gauge is the absolute maximum headspace. If a bolt closes fully on the Field gauge then the firearm is not safe to shoot. If the bolt closes with slight resistance with the NOGO gauge, then it's still within spec.

[bfoosh006]

FWIW... The PTG Go, NoGo gauges are used in both the .308 and longer 7.62x51 milspec chamber.

".308 Winchester


22 - 243 Win, 243 Win, 260 Rem, 270 - 08, 270 – 308 Win, 338 Federal, 338 Federal CIP, 338 - 08, 338 - 358 Win, 358 Win, 6.5mm Panther, 6.5mm - 08, 7mm - 08 Rem, 7mm – 308 Win, 7.62mm NATO, 7.62mm x51

And PTG also says to remove the ejector and extractor.

And..

The .308 Winchester chamber headspace is between 1.630 and 1.6340 inches (SAAMI Info). The 7.62x51mm NATO is between 1.6355 and 1.6405 inches.

[44 AMP]

Sounds to me like you're doing it correctly. It's been a long time and I'm just going from memory and my experience with GI M16s in the 70s, but that's how we were trained to do it.

Upper off the lower (or hinged open), gauge in the chamber, push the bolt carrier by hand until it stops. Firm push but no hammering, tapping or hard shove. If I remember correctly the gauges we had had relief cuts in the base to clear the extractor and ejector, so we didn't have to remove them from the bolt for an accurate reading.

If the bolt carrier stuck out past the end of the upper, on the go gauge, it was bad. If it DIDN'T stick out on the No-Go and field gauge, it was bad (the other way).

I would expect the same to be true with the AR 10 series, but I'm not an expert on them. Am interested to hear what the gunsmith says. Do let us know, and yes, to me its just a friendly conversation, also, and I agree, if I could see what you were doing, we'd save a lot of typing!

[Metal god]

Im at the range now and brought the PA-10 with me .

Federal 150gr power shok measures
1.616 before firing and 1.626 after . That is 10 shots but 2 of the 10 only grew .009

In contrast , same ammo in my Ruger precision rifle measured
1.616 before and 1.618 after .

The PA-10 fails the gauge and the Ruger passes it . That can clearly be seen in there respective fire formed cases .

I’ve only fired those 10 shots in the PA-10 and not going to shoot any more today . I will say the cases are coming out way better looking with no tool marks compared to the last barrel . This one has a much smoother chamber . I also do not see any bloating at the web at this time .

EDIT

Got home and checked a few things . The fire formed cases measure .003 longer then the PTG brand gauge PSA uses to check there headspace .

Oh and anther interesting tid bit . I buy all my once fired LC brass from the range I shot at today . The military uses are ranges and the primers are still crimped in . Want to guess what those measure ? 1.626 to 1.627

After all the measuring and comparing I've done . I have no doubt that PSA has there barrels/chambers cut to 7.62x51 NATO specs and are stamping them 308 Winchester .

[zeke]

Given PSA's previously reported problems with too tight of chambers, the chamber appears to be cut for reliability. Another item is that measuring the datum on semi autos may not be accurately reflective of of the chambers datum as semi's can "stretch" brass on extraction. Likely the camber is cut longer, just not to the extent you are measuring from the brass.


If memory serves, Federal commercial brass has the shortest shoulder datum have measured yet.

[Bart B.]

The .308 Winchester chamber headspace is between 1.630 and 1.6340 inches (SAAMI Info). The 7.62x51mm NATO is between 1.6355 and 1.6405 inches.

Compare those chamber dimensions to that of the ammunition:

http://forums.thecmp.org/showthread.php?t=146769

Compare case to chamber differences to see how case head clearance to bolt face when round fires will sometimes be a crush fit if the bolt closes full into battery. And several thousandths clearance with maximum chambers and minimum ammo.

[Metal god]

Another item is that measuring the datum on semi autos may not be accurately reflective of of the chambers datum as semi's can "stretch" brass on extraction.

I agree but all 10 cases pretty much came out the same . When that happens I consider those measurements representative of the head space and bump my shoulders .003 for semi auto's and have never had an issue with my sized cases chambering . I had some light loads , think they were PMC . That gave me very erratic head to datum measurements . I how ever have had relatively consistent measurements when measuring higher pressure full power loads regardless if fired in a bolt gun or semi auto .

Originally Posted by Me

After all the measuring and comparing I've done . I have no doubt that PSA has there barrels/chambers cut to 7.62x51 NATO specs and are stamping them 308 Winchester .

Originally Posted by in link from BartB

SAAMI .308 Winchester:
GO: 1.630 in.
NO-GO: 1.634 in.
FIELD: 1.638 in.

FN FAL:
GO: 1.6325 in. (FN & Brit/commonwealth. Canadian is 1.6315 in.)
NO-GO: 1.638 in.
FIELD: 1.640 in.

7.62 NATO (M14 US MILSPEC):
GO: 1.6355 in.
NO-GO: 1.638 in.
FIELD: 1.6445 in.

Originally Posted by a poster in the link

Ok you missed it again, both 308 WIN and 7.62 NATO are the same period. The headspace specifications for the cartridges are SAMMI 1.627- 1.634, NATO 1.628-1.634. The only reason NATO went to the larger chamber was for battlefield reliability,

Ok just so I understand , is the NATO chamber cut larger ? You have guys posting specs that say yes and others that say NO PERIOD then add they went to a larger chamber ???? It's like saying , They are the same but not really . So is she pregnant or not ?

[Metal god]

Originally Posted by stagpanther

This thread has crossed into the absurd zone--I'm out.

No it hadn't , but it's about to right now .

I've decided to keep the upper

Err Wait What ???? Hang on a sec , hear me out . No I'm not happy with it , well the headspace aspects of it I'm not , in fact quite disappointed really . How ever I've been doing some research into getting another upper from another manufacture or building one from the ground up . Most that I see with similar designs minus the poor headspace are well above the cost of this one and building one out from scratch would be pricy as well .

So my thinking is if I keep what I have and just replace the barrel and bolt in the very near future it will only cost me is another $300-ish dollars . The fact I already have the upper , M-lock rail , gas block , carrier , charging handle etc . Means I don't need to buy all that stuff to build another and based on my research so far I can't get all that for the price I have into this complete upper now . $350 is all I'm out so far , not including the PTG gauge lol .

By keeping it , I'm well on my way to having the proper set up rather then starting from scratch .

So Stag , you're right this thread did get into the absurd

I'm not sorry for starting the thread or all the back and forth with you all . I've never bought a firearm or it's critical components that were so out of spec before and really did not know the best way to process it in my mind . I enjoyed you all helping me through it ( yep even you stag ) it really helped me work through this process . IMO PSA is knowingly sending sub par to boarder line dangerous products out that will eventually have serious headspace issues in likely under 10k rounds as the lugs wear some . Which we all know does not take long in a semi auto . Although I'll try not to bad mouth there PA-10 line I will be strongly discouraging anyone from buying them at this time . They are BARELY worth buying haha

Thanks again for all your help .
MG

[stagpanther]

Well, I'm stepping back in and first let me apologize, I was really reacting to a poster who was insinuating that I was advocating that you do something that could place you and the gun in jeopardy--I was not.

That said, based on my experience of having built dozens of both AR 15 and AR 10's (and I still consider myself as having just basic knowledge; like the more you know the more you know that you don't know)--what I've learned is that it's not enough to simply find out something is wrong and start throwing parts at it to see if the issue goes away, but in my case I have a compulsion to find out definitively why something is wrong and then logically arrive at a fix. What is compelling about your situation is that the manufacturer has twice said your upper is compliant, and you have asserted that it is not--plus provided evidence of cartridge cases that appear to have been on the verge of potential catastrophic failure.

[ed308]

So my thinking is if I keep what I have and just replace the barrel and bolt in the very near future it will only cost me is another $300-ish dollars . The fact I already have the upper , M-lock rail , gas block , carrier , charging handle etc . Means I don't need to buy all that stuff to build another and based on my research so far I can't get all that for the price I have into this complete upper now . $350 is all I'm out so far , not including the PTG gauge lol.

If replacing items, replace the barrel first and see if your bolt works with the new barrel. It probably will work.

[Metal god]

What is compelling about your situation is that the manufacturer has twice said your upper is compliant, and you have asserted that it is not--plus provided evidence of cartridge cases that appear to have been on the verge of potential catastrophic failure.

For the most part correct . They did confirm the first barrel was out of spec and replaced it . This appears to be true based on the condition of the cases fired in the second test with the "repaired" upper . Based on how the second set of cases looked after firing it appears to me there is defiantly a different barrel installed . I believe the headspace is generally the same as the first barrel .

Not sure how much any of you read that other thread I linked where I talked about those tool marks . In that thread it was noted that the Winchester cases weighed 30gr less then the Federal cases . Usually I'd say case weight does not effect much when comparing it to others . How ever when the difference is 20 or 30gr . It's a clear indication of a thinner or thicker walled case depending which way you're looking at it . IMHO the excessive headspace of this rifle and the thin walls of the 156gr Win cases is a bad combination to be working together . I just don't think those Winchester cases can handle the extra growth under pressure this chamber creates .

I'll will be hand loading almost exclusively for this upper until I replace the barrel . I've done some preliminary measuring and it looks like I'll need to size cases for this rifle .005 to .006 longer then I do for any of my other 308 rifles and that will be setting the shoulders back .004 . Needless to say these cartridges will not fit any of my other 308's . Now I do have some proprietary loads for my other rifles but that mostly has to do with COAL , not case headspace . I do have two match plinking loads that shoot well in all my 308's but those will have a head clearance in this upper of .007+ rather then the .002 or .003 they have in the others . I'm not going to stretch that brass out by shooting it in this upper .

I bought some once fired LC-15 cases when I was at the range that measure pretty much what my fired cases from this rifle measure . This means I should be working this new brass less and it should work out fine . I started prepping it out today ( deprimed and wet tumbled ) and it's drying now . I also ordered some 147gr projectiles this afternoon for this rifle . I only have match bullets that I shoot in my other 308's and I don't feel like wasting them on this upper right now

If replacing items, replace the barrel first and see if your bolt works with the new barrel. It probably will work.

Yes , I'll do that first and I still plan to take it to a gunsmith , just haven't got to it yet . Maybe Mon or Tues because I'll be in the area of the smith I plan to take it to . Also now that I'm keeping it I'll be less reluctant to pull the barrel and strip the bolt .

Oh and FWIW PSA did send me a return shipping label to return the upper if I want . So they are still willing to take it back but for reasons described in my last post I will not be returning it . Thought I should at least mention that and that it is my choice to keep it rather then them not honoring there warranty .

[stagpanther]

Send it back for a refund--unless you are sure you know what the problem is and that it can be easily fixed. Otherwise, you are assuming responsibility for any other problem that might happen IMO.

[zeke]

The only way have found to have a common load for all my 308's is to use a sb die set to minimum base/shoulder datum. Have 2 target rifles with minimal base to shoulder datum, and another one that with tight chamber dia. Along with several semi's with much looser chambers.

Have not found the win 308 brass to be "weak" in any manner, but it is easier to determine the expansion ring. The case volume does noticeably affect velocity's.

None of my shorter 1::10 in twists shoot the 147/150 grainers very accurately.