Continuation of Gopher's issues

98Z5V · July 15, 2018

1 hour ago, bfoosh006 said:

And again, "correct" or not ... mine still function fine with a short gas tube.

All I am saying is the short distance from the gas tube into the PSA large frames has made no discernible function issues for me and mine. So, clearly it is working for all my 18", 20", and 22"uppers and 12.5" I helped my friend build.

98Z5V... I would love to get together and spend hours discussing our collective observations and experiences... I am sure you and I could ramble and chatter over the most odd AR issues .

Same here - it would be a riot, for sure... :laffs:

In reference to the stuff I bolded above - your guns are only running because everything else is "right enough." As soon as you toss a gas port in there that's too small, no bueno. Everything turns to shiit. As soon as you throw a stronger (correct) recoil system in there, again, no bueno. Lack of gas pressure is fighting a proper (and not weak) recoil system.

It's exactly why I said this, in that other linked thread:

It's come up that the carrier key sits further back on the 308AR than it does on an AR15 - it's in the exact same place from the front of the carrier back to the front of the key, but that 308AR bolt is alot bigger than an AR15 bolt, and when the bolts are seated in the carrier, in the firing position, that key is further back on a 308AR.

That's issue #1.

Next, Armalite vs. DPMS (and AR15) gas systems. Why Armalite gas tubes are longer than standard AR15 gas tubes (and DPMS_based LR308 parts), I have no idea. Why DPMS uses AR15 gas tube lengths for 308ARs, I have no idea... However, I DO know that Armalite knows their shiit, and they have a scientific, tested, proven reason for making AR-10 gas tubes longer. Whatever reason that is, you can know that it's a good one. Pat Raley could tell us all about it, I'm positive.

That's issue #2.

Next, that carrier key overlaps the end of that protruding gas tube, and it's for an exact distance/measurement. It's THAT WAY so the bolt carrier receives the proper amount of gas, for the proper amount of time, in order to properly cycle the semi-automatic weapon. Once that bolt carrier assembly has made enough rearward travel, it disengages from the end of that gas tube, and the remaining gas is discharged directly into the (now open) upper receiver. It's the excess gas you see coming out of the ejection port when your buddy fires his weapon...

That is issue #3.

Now, that leaves us here - with a gas tube that is NOT the proper length, and it's short by 3/16", that bolt carrier is NOT receiving the proper amount of gas, for the proper amount of time, and it's not fully cycling that bolt carrier assembly with the proper amount of force that it was designed for. It might cycle, but it's NOT going to cycle as it was designed to do... THAT cannot be argued. It's science and math. Done.

It's more than a gas pressure thing,from the power of the round. It's the timing of the gas system that gets completely out of whack. You toss on another out-of-spec dimension somewhere else in the complete operating system, and you have a gun that functions like shiit.

bfoosh006 · July 15, 2018

18 minutes ago, 98Z5V said:

Same here - it would be a riot, for sure...

In reference to the stuff I bolded above - your guns are only running because everything else is "right enough." As soon as you toss a gas port in there that's too small, no bueno. Everything turns to shiit. As soon as you throw a stronger (correct) recoil system in there, again, no bueno. Lack of gas pressure is fighting a proper (and not weak) recoil system.

It's exactly why I said this, in that other linked thread:

Agreed... I would like to know if PSA has changed its "normal" 0versized gas ports... but my April manufactured ones ( rifle length gas ) still had ample gas flow. Enough that I still installed all the fix the " overgassed " issue parts.

And... all the PSA's ran in OEM configuration... and were "overgassed"

What are your thoughts on that "peened" area in Gophers upper ?

98Z5V · July 15, 2018

3 minutes ago, bfoosh006 said:

And... all the PSA's ran in OEM configuration... and were "overgassed"

What are your thoughts on that "peened" area in Gophers upper ?

I think people confused "overgassed" with that weakass recoil system, brother, honestly. Fuk me, that recoil spring I got from Gopher isn't even fit for duty in an AR15, let alone a .308 Win-powered load. The buffer is too damn light (my saying of "not enough a$s to control the mass"), and the receiver extension has too much internal depth, so your BCG crashed into the ears on your lower receiver. What a goatfuck of a recoil system.

On that peening, I can't say from pictures. I need to get that upper in my hands, and Gopher and I will work that out. I'm gonna fix this upper assembly, and he's gonna have a fully functional rifle. I will find out what the hell is going on with this thing, and I will fix it.

I don't think there's a gas leak anywhere - that takes care of itself after about a dozen rounds. Nothing is ever air-tight when you first build it, gas escapes from the gas block and the gas tube (into the gas block). Carbon fouling seals that up pretty quick. I think he's got a gas port issue, and it's too small. Possibly some other issues. If I find some machining issues with that upper, I will be posting it here, letting PSA know about it, and getting Josiah/Jamin involved.

bfoosh006 · July 15, 2018

Tenacity... I hear ya... I went through the same thing with my first PSA's

98Z5V · July 27, 2018

PIcked up Gopher's upper today, and I've been in it all this afternoon. It won't pin to an Aero Precision M5 lower. There are some things I'm seeing right now that are slightly different from the AP M5 stuff, and I'll get all into that. This is gonna be an interesting weekend. :thumbup:

I will pull out the DPMS LR-308 lower and the Matrix Aerospace lower, and the other AP lowers, and be doing some serious upper/lower fitment exercises and comparisons with those other uppers...

Edited July 27, 2018 by 98Z5V

edgecrusher · July 27, 2018

Thought I heard you pining away while we were on the phone, right on!

mley1 · July 27, 2018

This should be very interesting. Thanks for doing the work to find out what's going on with Gophers .308. I looked at my gas tube position in my upper. It too is short. So, I suspect that my recoil system may be very similar, if not the same, as Gophers. I did the mods I did to get it to function because early on I was experiencing the bcg hitting the receiver, the appearance of over gassing.......etc. Same symptoms.

98Z5V · July 27, 2018

Gas port data: PSA Stainless .308 barrel, "midlength" gas system. 0.073" fits, 0.076" does not fit. I'm thinking this gas port is too small, and needs to be around 0.080". That would explain the weaker recoil system that it is shipped with - it's underpowered.

A PSA PA-10 Gen 2 upper receiver will not work on an Aero Precision M5 lower. It won't. You can't close the receivers and pin the rear takedown pin, because the relief cut in the upper (for the bolt catch paddle) hits the bolt catch paddle. It's almost like the relief cut in the upper receiver isn't cut high enough. If you slightly depress the bolt catch, the upper will close on the lower, but you have to tap the takedown pin in there with a small poly hammer. You can only do this if the charging handle is not in the upper. If the charging handle is in the upper, the charging handle makes contact with the Aero M5 lower receiver, and the halves will not close to a point where you can pin them together. If you forced this to happen, you'd bind the charging handle in place, and never be able to hand cycle the weapon via the charging handle. I used the standard PSA charging handle, and a BCM Gunfighter charging handle, same results.

I can't physically try the PSA upper on a Matrix lower - the Matrix I have is the Armalite-type angled cut, so the two will never physically fit together. I forgot about that when I said I was gonna try it.

Moving on to the genuine DPMS LR-308 lower now...

Edited July 27, 2018 by 98Z5V

Gopher · July 27, 2018

I see some time me buying 98Z5V a beer or 10! Thanks again Bro!

98Z5V · July 27, 2018

Baby steps, brother, baby steps... I need to find a gun I've got that this upper is gonna run on!... :laffs: I'm digging that DPMS out now...

Armalite AR-10 Carbine gas tubes are out-of-stock everywhere, and I'm on several email-notification lists right now for them. I've got one here, so that won't slow us down. Gas port size will come up. FSB will get chopped, and re-pinned to the barrel. This thing is gonna run this weekend, even if I have to take two guns completely apart and mount your barrel, charging handle and BCG into an Aero setup to run it. Hopefully, the DPMS lower and PSA upper play well together... :thumbup:

Armed Eye Doc · July 27, 2018

44 minutes ago, Gopher said:

I see some time me buying 98Z5V a beer or 10! Thanks again Bro!

@98Z5V likes Jameson, so I have heard. :thumbup:

98Z5V · July 27, 2018

Jameson likes me, too! Tends to make me slow the next day, though. VERY slow... :lmao:

98Z5V · July 27, 2018

Okay, basic PSA upper, no BCG no charging handle, it damn sure goes into a DPMS lower alot easier, but there's still that interference with the bolt catch paddle. You have to slightly push in on the bottom of the bolt catch (like you were trying to engage it, and lock a bolt to the rear). So, you have to hit the catch a little, and rotate that paddle out of the way of where it's hitting in that cutout on the upper. If you don't, and you were to slam the upper and lower together, it would move that paddle on it's own, anyway. That make any sense, with words only?...

So, here's the deal - when you pivot that bolt catch a little, you're raising the internal part, that would grab the bolt face - its not flat, like it should be, resting on that upper flat surface of the lower receiver. It's not "at rest" and flat, it's raised.

@Gopher,you ever notice that on your PSA lower, brother? Troubles closing and pinning the receivers unless you kicked that thing outta the way a little? If it happened to you, then I'll relieve that area in the upper receiver a little, so it doesn't happen anymore. I don't want to do that, if it's only an issue I'm having, and it doesn't happen to you. Test fit with BCG and CH coming up.

UPDATE: Yeah, BCG and CH in the PSA upper, pinned to the DPMS lower. It pins, just fine - gotta move the bolt catch a smidge. Won't function. Will not. That bolt catch is raised a little, to fit the upper and lower together, and the BCG drags on it, and stops all rearward progress in less than one inch of BCG travel. It won't cycle.

So, a PSA Gen 2 upper will not work on an Aero Precision M5 lower receiver, and it will not work on a DPMS LR-308 lower receiver. It won't even pin down on the AP M5. The only way to make it work on a DPMS LR-308 lower is to either trim down the paddle on your bolt catch, or relieve that shallow area cutout in the PSA upper. No other way.

So. One of two things is happening at PSA. They're using their own proprietary 308 bolt catch, that's shorter than a DPMS LR bolt catch, and shorter than the AP M5 bolt catch... OR... Their Gen 2 lower is different, and it "sits" these standard 308 bolt catches lower in the frame. That would be a big machining difference from those other two samples.

Edited July 27, 2018 by 98Z5V

98Z5V · July 27, 2018

PIcs of what I'm talking about...

First, gas tube is too short. Don't screw yourself on the available gas impulse, take advantage of all that's available, by design (by Eugene Stoner's design). Gas tube should come to the very center of the cam pin cutout in order to do that. You can't do that when the tube is too short.

Second, the gas port in the barrel let 0.073" pass, but 0.076" did not. That gas port needs opened up, it's too small. It needs to be 0.080" minimum, and might go up from there.

Third, the height-over-bore on a .308 AR is higher than on the AR15 guns. The cartridge is larger, the upper receiver is larger, etc. It's a fact. If you were to measure from the center of the bore to the center of the gas tube diameter, the 308AR is a bigger beast than the 15. This is an AR15 midlength gastube. The AR-10 Carbine gas tube has larger bends, and it comes up higher, to account for that increased height-over-bore. When you use an AR15 midlength gastube on these things, you have to "bend" the gas tube to make it work (That info is coming up). This is a picture of the AR15-sized OD on the barrel nut - notice that it doesn't even engage the gas tube. Usually, you have to make sure that barrel nut is precisely aligned, or you can't get your gas tube through one of those teeth. Not on this thing. You could torque that barrel nut to whatever you wanted, and you don't even have to worry about gas tube alignment, at all. Just slap it together.

I'm sure the ID is larger, to fit the larger diameter barrel. I guess this makes it easier to assemble, though, and you can just used an AR15 Armorer's Wrench on it. There's a reason there are .308AR Armorer's wrenches, though - to handle the larger barrel nut. My preference for one of those is PRI. They make the beefiest ones. :thumbup:

Now, sine an AR15 midlength gas tube was used, and it doesn't have the appropriate bends for the larger height-over-bore of a large-frame AR, you have to "tweak it upwards" out of the gas block in order to get it into the upper receiver, and that higher hole in the upper receiver... Based on that, there's alot og carbon buildup - which is gas leakage at the gas block exit...

Pic with flash:

Better pic of the carbon buildup, no flash (but a shiitty, unfocused pic)...

Edited July 27, 2018 by 98Z5V

bfoosh006 · July 27, 2018

1 hour ago, 98Z5V said:

Gas port data: PSA Stainless .308 barrel, "midlength" gas system. 0.073" fits, 0.076" does not fit. I'm thinking this gas port is too small, and needs to be around 0.080". That would explain the weaker recoil system that it is shipped with - it's underpowered.

A PSA PA-10 Gen 2 upper receiver will not work on an Aero Precision M5 lower. It won't. You can't close the receivers and pin the rear takedown pin, because the relief cut in the upper (for the bolt catch paddle) hits the bolt catch paddle. It's almost like the relief cut in the upper receiver isn't cut high enough. If you slightly depress the bolt catch, the upper will close on the lower, but you have to tap the takedown pin in there with a small poly hammer. You can only do this if the charging handle is not in the upper. If the charging handle is in the upper, the charging handle makes contact with the Aero M5 lower receiver, and the halves will not close to a point where you can pin them together. If you forced this to happen, you'd bind the charging handle in place, and never be able to hand cycle the weapon via the charging handle. I used the standard PSA charging handle, and a BCM Gunfighter charging handle, same results.

I can't physically try the PSA upper on a Matrix lower - the Matrix I have is the Armalite-type angled cut, so the two will never physically fit together. I forgot about that when I said I was gonna try it.

Moving on to the genuine DPMS LR-308 lower now...

That gas port size is in line with my PSA's....

98Z5V · July 27, 2018

1 minute ago, bfoosh006 said:

That gas port size is in line with my PSA's....

That doesn't make it right. THink what you want, that's too damn small.

98Z5V · July 27, 2018

That would explain the weaker recoil system that it is shipped with - it's underpowered.

Edited July 27, 2018 by 98Z5V

bfoosh006 · July 27, 2018

1 hour ago, 98Z5V said:

Okay, basic PSA upper, no BCG no charging handle, it damn sure goes into a DPMS lower alot easier, but there's still that interference with the bolt catch paddle. You have to slightly push in on the bottom of the bolt catch (like you were trying to engage it, and lock a bolt to the rear). So, you have to hit the catch a little, and rotate that paddle out of the way of where it's hitting in that cutout on the upper. If you don't, and you were to slam the upper and lower together, it would move that paddle on it's own, anyway. That make any sense, with words only?...

So, here's the deal - when you pivot that bolt catch a little, you're raising the internal part, that would grab the bolt face - its not flat, like it should be, resting on that upper flat surface of the lower receiver. It's not "at rest" and flat, it's raised.

@Gopher,you ever notice that on your PSA lower, brother? Troubles closing and pinning the receivers unless you kicked that thing outta the way a little? If it happened to you, then I'll relieve that area in the upper receiver a little, so it doesn't happen anymore. I don't want to do that, if it's only an issue I'm having, and it doesn't happen to you. Test fit with BCG and CH coming up.

UPDATE: Yeah, BCG and CH in the PSA upper, pinned to the DPMS lower. It pins, just fine - gotta move the bolt catch a smidge. Won't function. Will not. That bolt catch is raised a little, to fit the upper and lower together, and the BCG drags on it, and stops all rearward progress in less than one inch of BCG travel. It won't cycle.

So, a PSA Gen 2 upper will not work on an Aero Precision M5 lower receiver, and it will not work on a DPMS LR-308 lower receiver. It won't even pin down on the AP M5. The only way to make it work on a DPMS LR-308 lower is to either trim down the paddle on your bolt catch, or relieve that shallow area cutout in the PSA upper. No other way.

So. One of two things is happening at PSA. They're using their own proprietary 308 bolt catch, that's shorter than a DPMS LR bolt catch, and shorter than the AP M5 bolt catch... OR... Their Gen 2 lower is different, and it "sits" these standard 308 bolt catches lower in the frame. That would be a big machining difference from those other two samples.

PSA has a bolt catch unlike anyone else's... believe me, I have checked... the nub that engages on the rear of mag follower is huge compared to everyone elses... and If memory serves me right... the pivot pin hole is in a slightly different position.

"Troubles closing and pinning the receivers unless you kicked that thing outta the way a little? " ... never had that issue with any of my 6 complete Gen 2 PSA large frame AR's

Edited July 27, 2018 by bfoosh006

bfoosh006 · July 27, 2018

10 minutes ago, 98Z5V said:

That doesn't make it right. THink what you want, that's too damn small.

Lol... I hear ya... but PSA does a lot of "different" things... so for me and mine, IMHO it is a Ford V. Chevy kind of thing.

And... at the risk of being a PITA... all mine ran in OEM condition ( albeit, over gassed and seriously fast cyclic speed ) ... so yea, the parts do function... is there most likely a better mouse trap... heck yea. But not in the PSA price range.

Interesting on the gas tube to barrel nut position... mine have all been FF'd so no USGI style barrel nut.
If you measure the picatinny rail height, from the bottom of the uppers barrel "hole......and compared to a DPMS upper and Aero...( etc ) ....You are gonna find PSA has a completely different height there as well... that's why no after market FF handguards picatinny rails match the PSA's upper picatinny rail height.... No DPMS high tang / low tang/ ODIN works. after market FF tube.. will match the PSA uppers picatinny rail height. Only the PSA / JL Billet made ones will

Edited July 27, 2018 by bfoosh006

98Z5V · July 27, 2018

Now, moving to upper-to-lower fitment, on the AP M5 lower.

I mentioned it above - the cutout in the upper on the PSA Gen 2 isn't high enough to pin it to an Aero M5 lower, without bolt catch interference. Here's where it hits - and there's some silver aluminum there - I don't think I did that. That might have been from before, when Steve was trying to close his own gun. I'll touch it up, no matter what. It's a fitment issue on the AP M5.

Here's where that leaves you, when trying to close the upper and lower, if you don't move it out of the way...

Never gonna happen, won't ever pin together, if you don't move that bolt catch from what it's interfering on...

Once you kick it out of the way, you're close, on the AP M5... Look CLOSE in this pic at that lower receiver and upper receiver fitment, at the top! Aero M5 will never work on a PSA PA-10 upper, because of that...

This is what your bolt catch looks like, though... you can see that it's already raised - it's not flat against the lower shelf, at rest...

Here's the standard PSA PA-10 charging handle, and how it's clamped down on the top of the upper receiver - and it's nowhere in position to get pinned on the takedown pin.

The BCM Gunfighter was a cutout on the underside of it's charging handle for things like this, but it's not gonna make it either, not with the M5 lower dimensions... It's nowhere near being in a position to pin, in this pic...

98Z5V · July 27, 2018

4 minutes ago, bfoosh006 said:

PSA has a bolt catch unlike anyone else's... believe me, I have checked... the nub that engages on the rear of mag follower is huge compared to everyone elses... and If memory serves me right... the pivot pin hole is in a slightly different position.

"Troubles closing and pinning the receivers unless you kicked that thing outta the way a little? " ... never had that issue with any of my 6 complete Gen 2 PSA large frame AR's

Fanboy it up all you want, brother. The dimensions on this setup have some serious issues. It's completely proprietary, just in frame dimensions. I'd rather fight a combination of trying to make an Armalite lower fit a DPMS upper with RRA guts.

That's just receiver dimensions, I'm talking about. That doesn't even account for functional issues that I'm trying to solve.

You have the connection with PSA - make sure they see this thread. :thumbup:

98Z5V · July 27, 2018

1 hour ago, 98Z5V said:

UPDATE: Yeah, BCG and CH in the PSA upper, pinned to the DPMS lower. It pins, just fine - gotta move the bolt catch a smidge. Won't function. Will not. That bolt catch is raised a little, to fit the upper and lower together, and the BCG drags on it, and stops all rearward progress in less than one inch of BCG travel. It won't cycle.

So, a PSA Gen 2 upper will not work on an Aero Precision M5 lower receiver, and it will not work on a DPMS LR-308 lower receiver. It won't even pin down on the AP M5. The only way to make it work on a DPMS LR-308 lower is to either trim down the paddle on your bolt catch, or relieve that shallow area cutout in the PSA upper. No other way.

So. One of two things is happening at PSA. They're using their own proprietary 308 bolt catch, that's shorter than a DPMS LR bolt catch, and shorter than the AP M5 bolt catch... OR... Their Gen 2 lower is different, and it "sits" these standard 308 bolt catches lower in the frame. That would be a big machining difference from those other two samples.

So, all those pics above were trying to get something functional from the PSA lower and any one of the many AP M5 sets that I have. Fail. That description above ^^^ is the mating to a true DPMS LR-308 lower. It doesn't work...

I have two solutions for Gopher, and I need to hear back from him. I'm fine with either one, but I need to hear from him - there are marks on that upper, and the bolt catch paddle cutout in the upper. It's happened before. I can relieve that, and make it higher, and cerakote that upper. Never know it was worked on.

I'll do that, if he's had that issue before. If he HAS has that issue before, it will affect his rifle function.

Or, the upper is almost apart. I'lljust build that barrel into an AR M5 set, and solve the functional issue in it (gasport size, gas tube, tune it to a real recoil system, etc.)...

98Z5V · July 27, 2018

I have options. Two options, when you look at the above. There is a third option: I will not hesitate to relieve the backside of the bolt stop paddle on my DPMS LR, so it will clear on that PSA upper. That's not gonna bother me a bit, and it'll never affect the structural integrity or strength of a bolt catch. That can be done.

For the record, here's the lower that the PSA upper pins to, but it doesn't function because of that bolt stop cutout in the upper of the PSA... This is one bad bitch...

Edited July 27, 2018 by 98Z5V

bfoosh006 · July 28, 2018

" and there's some silver aluminum there - I don't think I did that."
You didn't do it, that is from the OEM PSA firearm... the paddle top would smack the upper when firing , I ground away some of the inside top on mine to prevent that. FWIW ...My original posts address that.

Wait... that is Gophers Bolt Catch ? "This is what your bolt catch looks like, though... you can see that it's already raised - it's not flat against the lower shelf, at rest.."
The one in your photo isn't even close to every PSA Bolt catch I have.. installed, spare NOS etc...

The photos show the wildly different BC style ... again PSA proprietary
PSA with its wider nub v. KAK / AERO style BC...
PSA on top
KAK no bottom...

98Z5V · July 28, 2018

The concerns of the peening issues in the upper, from previous pics. There's something there, and I said I wanted to get it on my hands and look at it before I commented. Well, there is something there, but it "clearanced itself..."

The BCG hit the upper and removed material from both the upper receiver and the BCG body (aluminum was removed from the upper, steel was marked on the BCG from that...).

It's on the cam pin cutout side of the receiver, which to me, tells me it was a machining operation that displaced metal, causing interference.

I'm no machinist. I'm no AR machinist. I don't know what steps-in-the-operation that things occur, when machining an AR.

I've certainly "machined" before, though. Every operation has an effect. Since this is the first time I've ever seen anything like this, I can only guess.

On other guns, I've not seen this. On this gun, it's here. Do you maching the cam pin cutout before you bore the cylinder for the BCG to ride in? If that's the case, then you'd never see this kind of stuff. However, if you machine the clyinder for the BCG to ride in, then you machine the cam pint cutout (too fast, dull bit, whatever), then you'll create an issue for your self, and the edges around that cam pin cutout will be raised - and create interference.

I can't blame this on the BCG machining, but something DID happen in the machining process in order for this kind of interference to occur, in the first place.

You machinists - you tell me. If you're not a real machinist, well, then... don't need to hear it.

I'd like to hear from @Matt.Cross and @308kiwi on this...

There is mild contact before the cam pin cutout, and there's some pretty decent contact after the cam pin cutout - when you're looking at the forward travel of a BCG...