808chx.irradicator

Found it. The title of the post is "LR-308 won't cycle. Please help so I don't have to pay my gunsmith any more money" posted by Mrj209. In that post is where I learned about really lubing it up and opening up the gas port diameter in the barrel. You were actually the one to mention it.

@98Z5V Um, how do you do that? Kinda new to forums so... let me look

ok, as per my Frankford Arsenal calipers, the gas port diameter in the barrel is 0.075" hopefully that clears up my numbers confusion.

@98Z5V Ok, I just put her back together today and don't want to tear her apart and take pics to answer these questions so I'll do my best. The gas block journal size on the barrel is 0.875, and that's the size of the internal diameter of the BA non-adjustable gas block. The gas port diameter IN the barrel is...actually let me go take a pic

@98Z5V The gas tube, spring, and buffer are all Armalite. Buffer weighing in at 5.35oz. The gas port on the barrel is .0750. In reading up on this in other posts its mentioned that the port size should be between .085-.095. But before I go doing that I think I'm gonna run the rest of the box and the 2 others I have with it well lubed first to see what happens.

Ran into something else. Don't know if it's important or not but thought I'd show it anyway. In inspecting the spent casings further I noticed 2 vertical scratches and between the scratches at the case opening its flattened out. The picture doesn't really show it very well, but in person its noticeable. My first guess would be the feed ramps? I'm sure the collective knowledge on this forum will know a lot more about this than me. I've built 'many' ar15's with practically no issues, so this is a first for me, but was expected in reading up on building 308's.

Also here's some pics of the buffer tube ID and the gas tube looking in from magwell.

Some recreated pics to show what I was dealing with at the range. After every fired shot this would happen. The case would fall back in when locking the bolt to the rear, and then I tip the rifle to get it out, load another one and so on.

@jtallen83 Thanks, that's what I've decided to do. "expect her to be a little tight to start" 😂😂😂 yah... I been looking for some 308 gauges but I guess they're a hot item, hard to find those damn Clymers

@dpeteIf I had go/no-go gauges I'd do it myself but for right now I'm not thinking it's the headspace...but we'll see 🤷‍♂️

@98Z5VSorry, Winchester brand. You know, the white box with red lettering and cowboy on it. They look like old stock cause the casings were really discolored, like they could've been previously fired. Yeah I believe the components are good, just need to figure out what the issue is. But on the good side my first 3 shots out of this rifle were really good, 2 rounds right on top of each other and the 3rd just right a bit, all fitting under a nickel and that was with a crappy 1-6 scope at 100 yds. So I have high hopes.

@edgecrusher At the time I bought the barrel no JP or Fulton bolts were available so I didn't get that option with Criterion. I purchased the complete bcg from Fulton separately and have reached out to Criterion about maybe sending it to them for headspacing, but haven't heard back from them. Since they sell Fulton bolts on their site I thought it wouldn't be a problem. I was thinking maybe I'll use a little Flitz and polish the lugs on the bolt and extension to see if that'd help??

@98Z5VThanks for the responses/help. Ammo? The only kind I could find, Win. 7.62x51 149 grain M80 fmj. I agree with the carbon fouling over loctite as far as sealing the gas system. I've torn the rifle all apart to check things out but I think I'll put it back together and lube the hell out of the bcg and see what happens.

I've read some of the posts on this issue already but thought I'd check with everyone first before acting. First off let me give you the components in question: 22" Criterion hvy hybrid barrel, non-adjustable Ballistic Advantage gas block, rifle length Rosco gas tube, Fulton Armory bcg, Aero Precision enhanced upper and M5 billet lower, rifle length tube (don't remember who from) and the Armalite buffer and spring. The gas port on the barrel is .075", the gas tube is half way down the cutout, the internal depth of the tube is 9 3/4", spring length is 13 1/2", and buffer is 5 1/4" at 5.35 oz. If it matters I'm running the LaRue mbt trigger. So my issues are that it'll fire, but won't eject the case properly, and the bolt won't lock back at all. Its as if it's under gassed. I've only fired 12 rounds through it so far, and thats feeding the rounds in individually. After reading up on this my guesses are that possibly the gas port needs to be opened to at l east .085 - .090, or that maybe I'm running the wrong buffer tube length. I mean, if the port size is .0750 maybe I should be running a carbine system? I've also read that maybe I need to run it extremely wet, which I haven't done. The fulton bcg fit to the criterion extension is REALLY tight! Sometimes I really have to pull hard on the charging handle to get that thing out of battery. Any thoughts? I'd rather try the carbine length tube first before drilling the barrel to see if that does anything. Well, I guess first I'd like to try lubing the hell out of the bcg and see if that does anyting. Open to any suggestions! Thanks

@LR308Shootin@45 I wish I could recommend something, but at this point there's none to be had anywhere on this island!