6point7Cummins

Good point. Thanks.

What's the problem with mix matching brands? For example CMMG lower with Aero upper?

Alright. Ordered rifle length buffer, spring, and new rifle ext. tube. Is making uppers from scratch parts (buying blank upper then adding barrel, bcg, gas block, hand rail, barrel but, etc) really that much more difficult for .308 variants? Do you all recommend buying complete upper or piece mealing? I do not want another mechanical failure. Are there any particulars to be aware of (I see a lot of bolts will come matched with barrels).

Yeah, I was looking just at the DPMS .308 section. I see it now. I'm retarded.

Sounds like the guy that put all this together really knew what he was doing... I'm gonna call Luth and see which extension it needs then order the correct buffer/spring. Thanks for the help. What I got also from these responses, the gas system length won't matter when purchasing the upper? Or do I need to make sure its rifle length to match recoil system?

Okay, correct me if I am wrong, but this buffer and spring combo appears to be carbine length...looks like the right buffer for a .308 also. I just need to make sure I get a carbine length gas system on my upper, right?

I looked at that chart and I'm lost. How do you know which one you need. There aren't any measurements. My extension tube is 9 5/8" deep. Here a pic

98Z5V, great info. Much appreciated. I'm guessing since this is a LR308 based lower, I'd be dealing with the carbine setups, shorter buffer like you said in a standard extension? I'll check the lengths on my buffer and spring. I have a feeling they are wrong.

Thanks Survival Shop. How can I know if I have correct buffer and spring? Should I just buy another? Is there something specific I should look for when buying one?

Thank you! Why does it "pain" you if you don't mind me asking? I was looking at uppers build by Ground Zero Precision. I think they use Aero Precision uppers... https://www.groundzeroprecision.com/collections/ar-10-lr-308-ar-large-bore-variant-upper-receivers/products/custom-ultra-match-ballistic-advantage-aero-precision-6-5-creedmoor-ar-upper-receiver-complete

Hello all, I purchased a built .308 upper, used, several years back (mistake No. 1). I then had a local FFL who claimed to be a manufacturer, who apparently knew nothing about .308s, build my lower (mistake No. 2). The weapon had a serious malfunction basically rendering the upper a hunk of garbage. Oh well...the builder reimbursed me for the money spent on the upper. Now I am ready to purchase an upper, from a reputable manufacturer. My question is, how do I know how to properly match an upper to my lower? The builder does not recall which parts he used, LR308 vs. Armalite. He "thought" Ar-10. Is it really crucial that the lower parts type match the upper or more crucial the upper is made from all matching parts? ive included some pictures of my lower. The last picture shows damage to buffer tube threads (only damage sustained to the lower). The buffer still threads just fine. Thanks for any help you guys can offer... .