98Z5V

You don't have an extraction issue - leave the two o-rings in there. Don't mess with them just yet. Lube. How much lube was on the BCG and internals of the upper receiver when you fired this rifle? Did you break down the BCG, remove the bolt, lube the gas rings on the bolt tail? How many rounds total down the barrel so far? You need to be able to shoot enough to seal the gas block to the barrel, gas tube to the gas block, with carbon fouling - to create a total gas seal there. If you were running this gun dry, that will be a painful process. This sounds like a gas problem... Rifle recoil system - that hardly ever gets screwed up, by any manufacturer. Worth looking into the buffer length, though. 5.200" is the length for the .308AR buffers, 5.900" is the length you'll see if an AR15 buffer was accidentally put in there - which could create this issue...

Only if it's a race gun. It's a mistake on their part on the gas port sizing. 16" rifle-gas in a .308 is a tough one to pull off. When they made them for Fulton Armory, the spec given to them was 0.105" - and they built what was ordered. Fulton barrels functioned fine.

@dubya, if you want, I'll buy your LaRue MBT2S triggers from you. JB Matt went to order the flat LaRue yesterday. He got an email stated there was a backorder, so he called them. The person he talked to stated that he hadn't even seen one yet, and they have 1,000 orders already logged for it. His wait time would be at least 10 weeks. He changed over to the traditional MBT2S, and it arrives next week. Just an update on the flatties...

That's comparing a 4.5lb combined pull (SSA, G2S, LaRue, many others) to a 3.5lb combined pull (SSA-E). Of course it's going to feel different. That extra pound costs money, when dealing with quality triggers (as all these are). Don't do it, brother. It's not worth (1) waiting for a sale to get it close to the price of the LaRue, and (2) it's not a better trigger than the LaRue. The LaRue is smoother than the G2S. I'm not saying the G2S is a bad trigger, not at all. The LaRue is better, and cheaper. Of note, I do have all triggers I've referenced in this post, and many more.

That's what I'm thinking, here... You might be sorely disappointed, Pat. Written reviews - not many: https://www.gradreports.com/colleges/sonoran-desert-institute Here is a Google page to some video reviews- some that I watched a year or so ago weren't that good... https://www.google.com/search?q=Sonoran+Desert+Institute+reviews&client=firefox-b-1-d&source=lnms&tbm=vid&sa=X&ved=0ahUKEwi6vYGlpabhAhXrwFQKHcm9DJMQ_AUIEygA&biw=1238&bih=572

My plan is working...

Sweet!

I've seen some stuff on them - and their radio ads play here. From what I looked up, it's nothing spectacular. I'll dig up some specific examples when I get home tonight…

Backdrop, backdrop, backdrop. That's all I cn say on that one. We've got it here, so I'm down with it. JBMatt will win, not matter what, and we already know what - especially shooting at an orange clay. He'll smoke it. Like, 10x better than any of us mortals can do it. The only issue I see here is with the 200 yard thing. Who it THAT GUY that's 150 yards downrange with the hand-tosser, hoping he can get it 50 yards?.... I'm not volunteering for that one...

Get after it, and see how it does - if it solves your problem, make sure to state that. I watched that video, that Matt linked, originally, before I made my posts in this thread. The only reason I'd think that's not a good idea is because it will support your barrel-to-receiver contact surface - except for the width of that cut in the shim. If you get some weird barrel harmonics, weird shot groups, stringing, whatever - suspect that thing first. It's worth a shot, literally, or many - in your circumstance. Give it a try. Let us know how it does. Who knows, it might be perfect. If that is a success, it negates all the people that say you have to "true" the upper receiver in order to have perfect, square contact between the upper and the flange. If you can prove that theory down, it would be EPIC against that practice. WAY EPIC. Personally, I'd like to see that. Too many people say you cannot possibly have an accurate AR unless you true the upper receiver, and "glue" the barrel in place - if you don't = never gonna be accurate. I've never trued one yet, not glued one yet, and I have some that are quite accurate. This test would seal the deal.

Your gunsmith isn't as well versed on ARs. ARs need a completely different kind of "gunsmith." AR15s don't count. This big-frame is a completely different animal, with all the variations (3 major), then all the screwed up aftermarket "manufacturers" that don't know what they're doing. This isn't common "gunsmith" territory.

I've stayed out of this, but that's not gonna work here. Barrel nut shims are plentiful, but the work on the outboard side of the flange, before the barrel nut goes on, and they're only for timing of the barrel nut. That won't work here. You can't get a barrel nut shim onto the other side of the flange, to take up slack between the flange and the upper receiver - unless you remove the pin. It's not going on backwards, on the barrel, to take up that slack, unless the pin comes out. You can DO THAT, because the pin doesn't go into the threaded part of the barrel - common misconception. That pin doesn't lock the extension onto the barrel, like alot of people believe it does. If you want to do that, pull the pin, install a 0.006" shim, and reinstall the pin. Done deal. OP, if you're seriously trusting your measurements, and you're a serious 55/10-thou out on that gap, then either deepen the channel in the upper by 55/10-thou, or sand the back of the pin by 55/10-thou. Neither one is going to cause you any headspace issues, or bolt locking issues. If it was me, I'd cut the upper, and be done with it.

Unless this is a brand new projectile from Hornady - they don't make a .308 projectile in the 140gr ELD-M variety. Have they not updated their website?

You talking about that sniper in the tree, brother? He's right here:

Another example of a piece of greatness with a March birthday - why am I not surprised... Happy Birfday, Mack!

That's a WHOLE LOT OF dwell time, too. Big difference than what's being discussed here.

I'm not offended - I think I'm proud!...

You bought TWO...

I swear, my two ex-wives were easier...

Now I have to buy them?! You need some new shoes, too, honey?...

Mine isn't - and your bedroom in Casa De Pain is open...

Okay, I'll take that. You need a scope level, then,since this is give-and take... I won't stop nagging until I see one on your rifle. Brace yourself for "bitchy-voice..."

Now you're engaging in Age-Discrimination, just because you're younger. This is why we can't have nice things...

Why are you always bringin' up old stuff?!