98Z5V

Oh, that gas tube is WAY TOO FUCKING LONG. I'll confirm that right now. That RRA LAR-8 gas tube. In a DPMS-based weapon. That possibly has a barrel with a gas port in the Armalite AR-10 Carbine gas system location. I'll confirm that for you.

Nope. That's definitely not what I mean.

When exactly was I "slamming your setup?" When was that, again? You need to understand something, and fast. You come here looking for information, help for your problem. We'll give you that. If you're a dickhead, you won't get help. We don't work like that, here - and that's what you need to understand. If you get all defensive, butthurt, and pissed off, that's on you. You stated information, we ask for more information, you get defensive - and you can just go. Bye. You haven't even made an intro yet, and told anyone here about yourself - we're a community. Not your information slaves. We owe you nothing. If we have information that you need - we don't HAVE to give it to you. Do you understand that? Drop your attitude. Go make an intro - and before you do, read this:

You've pieced everything together from a bunch of different manufacturers, on a platform that has no set standard. The reason I asked about your recoil system is for future issues down the road - as recoil system problems are quite common on this platform, that has no standard to follow. Any monkey off the street can make parts, "custom parts" and bullshiit parts - and we see it all. I asked that question, for YOUR benefit - to head off problems down the road, once THIS problem is solved. I hope you can understand that.

You're lucky - I was going to tell you to fuk off.

You might need an Armalite AR-10 Carbine gas tube here - that all depends on where X-Caliber placed the gas port in this barrel. They're not well known for great gas port diameters, either, so you might want to measure the diameter of the gas port while you've got this thing apart- especially on a 20" midlength system. This is quite the combination of parts, no two from the same manufacturer. What's your recoil system look like, for parts?...

You're gonna need those two quarters, then. No more, no less, to make that out-of-spec receiver extension work. Keep 'em in there.

You're good with that. RIfle extension is good, too.

Okay. Update the thread with your pic of your gun.

You're full of education lessons here. Do you know the exact length of that RRA gas tube, end to end? If not, can you find those dimensions? I'm not aware that they use proprietary gas tubes in their LAR-8 .308 ARs, but they might. If you don't know that length, and can't find that length, do you have the capability to remove the gas tube and measure it? That will be the only way to figure out what's going on here. The cam pin cutout appears to be in the normal location, without measurements. What is this "thing" on your gas tube in this pic? What is that, that's rubbing against the inside of your upper?

Pics, man. Take a picture of the upper, looking down into it, so we can see how far that gas tube extends into the upper. Also, what brand if midlength gas tube did you use on it? There's a definite solution, here. Get the pics in here. Why X-Caliber is using a midlength gas system on a 20" barrel boggles my mind.

Fuckin' SOLD OUT QUICK! I send the contingent of asian hookers to your work address, right? Last time I sent them to the house, that was bad, I remember...

Damn, nuke that pic.

I love how he's announcing parts arrival, and everything is plural...

I have two "long .308 Win barrels" - one is 18" and the other is 18.5". There's no need to go with a 20" for any kind of increase in accuracy or velocity, because any increase you'd see would be negligible. I do have a 20" barrel on a .260 Remington gun, only because that was the shortest I could find, without waiting for a custom barrel.

Well, that would be the key point here. "Properly set up AR buffer system" is not what he's working with.

It should be 7 5/8" internal depth, and 7 3/4" internal depth is 1/8" too much. That's 0.1250". One quarter is 0.069" thick. You need both of them - but you better verify the length of your buffer - it must be 3.250" long.

Measure the internal depth of the receiver extension, please.

I. AM. IN!!!

It's been "inserted." I'm not gonna say where, when, or what, but it's been "inserted." You get to deal with it now.

Concur - COMPLETELY! You think the biggest thing is the gas port - and I agree with that. Now I'm about to go South on you... I think the biggest thing to START with is a recoil system that will handle the pressure and power of these bigger cartridges. First. If your recoil system isn't gonna handle it, then you compromise everywhere else to make it work... 5.4oz buffer, minimum, if you're going crazy on a load, but optimum at that weight for normal charges, for the Big Frame AR, just to start with... You have to have a spring that's matched to that, too. Hell, the entire system was designed around that principle. Once you've got that - it's all about dwell time and pressure - which is all about gas system length and gas port diameter. I wish I could work in your shop, brother. Even on a vacation. We could fuk some shiit up. So many companies these days are literally "cheaping out" and building the cheapest buffers they can (means, tungsten and stainless is expensive, compared to steel and aluminum), so they "under-recoil" these things, and come up with a screwed up spring to "kinda" make it work. Directly downstream of that is making their gas ports right - or not. They often don't. People bitch, and think they need an adjustable gas block to tame down this vicious over-gassed .308 Win AR round... and here we go. It was never over-gassed. It was always "under-recoiled" because it was cheaper to build that way...

Yeah, compared to a $3,200 optic, when it does everything you stated you need - it won't hurt to try at all.

You don't need that much scope, then. You'll be fine with this one: https://www.primaryarms.com/primary-arms-4-14x44mm-riflescope-acss-hud-dmr-308-223-reticle-pa4-14xffp308 I run that scope to 845 yards on a .308 bolt gun with BORING repeatability, regularly. I run that same scope on two 5.56 guns, heavy loads, and do the same. I run the same version of that scope, in mil-dot only, on a 6.5 Grendel gun, and a 25/45 gun, and get out to the same distance.