98Z5V

That's on the money, for a 20" rifle gas gun with a 0.750 gas block journal diameter. 0.093"~0.096 is where you want to be on that barrel config. Make sure your gas tube ends (in the upper receiver) right in the middle of the cam pin cutout. That Stag I played with last week was good on gas tube length.

You guys should see how they do it in Korea...

That vid doesn't help anything, but it shows the round getting out of your gun. Side shot vid of the ejection port would have been better. I just worked on a Stag 20" rifle gas barrel, over the last two weekends, for my gun pusher. The gas port was too small. It was a carbine stocked setup, and had recoil system problems, too, but that shouldn't be your case. If you want to eliminate any guesswork on the recoil spring, use an Armalite EA-1095 spring or a Sprinco Red spring. Then, you'll know for certain that the recoil spring isn't the issue. Check your gas port diameter, and come back with what it measures. Use numbered drill bits, and use the shank of the bit to measure - not the drilling end.

@Cinders, can you get this done? Post the pic of the overall gun.

That must have been a severely fucked up PSA receiver, if only lapping the forward edge brought you from 2.5" to under an inch. Shows what they're putting out. I've never had a 2.5" group out of any Aero M5 set that I've built - never lapped one of them - and I have a pile of them now.

You are building a "regular gun" and you're using some serious Race Gun parts. I wish you luck.

Remington 870 shotguns?... yeah, that's PSA now. All your AAC suppressors? PSA owns them now. Let's just hope that PSA doesn't fuk up the warranty on AAC suppressors, and make it like their own PSA PA-10 "lifetime warranties..."

I don't think they're going under anytime soon, but if they do, they TAKE OUT alot of the market... Because... Here's the PSA piece of the Remington Bust-Up... JJE Capital Holdings LLC acquires DPMS, H&R, Stormlake, AAC and Parker brands JJE Capital Holdings IS PSA...

Absolutely. You can't blame the gas port diameter - or the gas port location -of the barrel that you're producing... On the specs that the COMPANY THAT BOUGHT YOU... ...told you to do... DC Machine can make a good barrel. They just need to do it outside of what PSA tells them to do. Kinda HARD to do that, though, when PSA owns your barrel-making company... The only reason any PSA barrels have any problems is because PSA is telling DC Machine the specs to machine them to. It's not because DC Machine sucks. PSA just doesn't know what the fuk they're doing... They own the company (DC Machine), so they don't care who's reputation they're dragging down...

Someone needs to skool those fuckers, hard. Because DC Machime - the barrel makers for PSA - are OWNED by PSA... Someone needs to make those fuckers smart - because PSA doesn't listen to feedback. PSA gives zero shiits about customer feedback. Over YEARS of information. If you have a hand in that, Matt - fix them. Because they're tragically fucked up. Fix their ceahp-as$ recoil systems, too. You HAVE TO SPEND MONEY TO MAKE MONEY. "Cheap" doesn't mean "Reliable." PSA doesn't get that. Never did, and doubt they ever will.

Looking forward to it - after this, I actually miss him... His design never gained traction - but it least it had a goal, a purpose, and a direction. Purpose, Motivation, and Direction. The 3 things you need to provide as a Leader, to your subordinates. Always. This clown couldn't explain his way out of a piss-soaked paper bag, for what his intention was for his own damn gun. What a joke.

^^^ Bare minimum, right there, with the spread being 0.093"~0.096". for a 20" rifle gas with a 0.750" journal size. But at least they got that one right to the functional area. Maybe they're learning, something.

Well, they got that one borderline right, at the very bare minimum then. With adjustable gas, if it was mine, I'd straight punch that thing to 0.096", make that 41 clear, and you have no penalty (with adjustable gas). That way, you know it'll always function. Once you upgrade that weakass recoil system that they sent you. You could skip fixing the wrong recoil system in the gun, and just use your adjustable gas block - but that's just putting the band-aid on the wrong cut...

I doubt they got it right. What's the largest (smallest, numerically) bit that DID clear your gas port? The 43, or the 42? Use the shank end of the bit to check the fit, not the drill end of it...

Not based on the drill bit you used, where you mentioned this today in another thread. The drill bit that you stated cleared, was not a 0.093" drill bit... And, 0.093" would be on the small side of the range...

Dave, your numbers are off, by what you stated in the other thread. What you measured wasn't a 0.093" gas port.

I've never ever had to lap an Aero M5 upper to get it to shoot great.

Double tap.

It's going too fast with the suppressor on it - it's overgassed when that can is on that gun. You need more buffer weight in there to slow that thing down, or you need an adjustable gas block to cut that gas back - only when the suppressor is on there. That's exactly what is going on. Most suppressors increase backpressure. Magazines and the interwebz call it "Suppressor Boost."

You have a 20" rifle gas barrel. What you're quoting is for an 18" midlength gas barrel, which should be 0.080"~0.085". Your 20" rifle gas barrel should be 0.092"~0.096", to run right. You have a weak recoil system, because that's WAY cheaper for them to build. They try to compensate for this with a gas port that's too smal, and commonly an AR15 gas tube that's too short. The adjustable gas block isn't on there because the gun is overgassed - it's on there becacuse it's under-recoiled. By the way - PSA used to void your "lifetime warranty" on their own gun, if you put an adjustable gas block on there to "fix" the under-recoiled issues... https://littlemachineshop.com/reference/numberdrillsize.php

I'm just quoting you, Matt, quoting him - so this isn't something you said, but him. Pretty fucking ironic that the information he's looking for has already been published.

They can be pretty cool, until they're not. As long as he's cool, let him stay. They tear up alot of bad things around them, and actually do good. Until they turn into a$sholes...

So, for that original UBR, the built-in extension was 7.000" deep. The UBR 2 setup was made at 7 5/8" deep.

Get an overall pic of the gun from the side. Need to get a general idea of where your eyepiece is in relation to the whole gun.