Vermonter

Thank for your reply! After trying the buffer tube on other rifles and taking some measurements the problem does indeed look like the lower is out of spec. I reached out to the vendor, and interestingly enough they say the manufacturer is no longer producing them, even though I bought these about two months ago. They have offered me a full refund, and are working to make things right. I asked if this was a known quality issue, and am awaiting a response to that answer. I have also asked if they offer any other 80 percent lowers in .308 to simply swap them out. Again, I'm awaiting an answer. I'll pass along more information as I have it.

Correct. The design of the UTG buffer tube is a machined shoulder. According to the instructions you torqe the tube to spec and you're done if memory serves me correctly. I do have other buffer tubes that I can try. In the next few days if time permits I'll see how other ones fit. As a note I actually called the Leapers/UTG customer service line and spoke with a rep. To the best of the knowledge of the guy I talked to, and the person he confered with they aren't aware of other people experencing the same problem.

Okay. Here are a couple of pictures. From looking at it I'd say the bore for the detent is at a slight angle.

Howdy folks. I'm new to the world of working with AR platform rifles. I have built several AR 15's with various 80 percent lowers with no real problems so far. I decided to work on a DPMS pattern LR 308 build using a forged 80% lower from Rightobear. My question is this. I purchased a complete upper from Bear Creek Arsenal with a 16 inch barrel along with a basic A2 stock kit from UTG. I've used the A2 style stock kit from UTG on a AR 15 build I did with very good luck, and was happy with the results. When I assembled the rifle, the buffer tube shoulders out and tightens well before the lip of the buffer tube has a chance to catch and retain the detent pin. If I simply remove the detent and spring, with a bit of patience I can retain the spring and buffer, simply close the upper and lower and all seems well. I have not attempted to fire the rifle yet, from what I can tell every function seems fine, the magazine seems fine, the bolt catch seems to function fine, and all features of the BCG appear to be A-Ok. Am I missing something? Am I making some kind of rookie error? From what I've been told and researched the .308 builds can be a bit more fussy thank working with the AR-15, is that a correct thought? Thank you in advance for input!