Looking for another AR to add to the lineup as a dedicated go-to rifle. Home defense, classes, and potentially scenarios where it will be run hard in training. In the past, many times a decade or more ago, I've seen SME's such as @DocGKR recommend manufacturers such as Colt, BCM, LaRue, and LMT. I am curious where this all stands in 2022. I seem to remember some complaints of BCM barrels having substandard accuracy and flaking chrome lining on an ar15 forum, and I do remember on this forum circa 2014 or so there were some gripes with Daniel Defense QC issues. In said thread, DocGKR stated: "Which vendors have contracts with government entities and use the TDP--that is a good clue..."
As far as I know, only Colt is able to use the TDP in the manufacture of their commercial rifles, and FN is not allowed to even produce their commercial ARs in the same plant as their military contract rifles using the TDP. I know Daniel Defense does have some contracts for barrels for the URGI (maybe uppers? not sure) and for sure rails. I was looking at the Daniel Defense M4A1 with the RIS II rail, even as I know quad rails have fallen out of favor. I've seen people often say that today's Colts are not on the same level as they were a decade ago. Other than a recall on some trigger groups I haven't heard of any issues, but as I understand it most of the parts are outsourced now and don't have the same inspection markings they did back when they were the primary supplier of M4s for the military.
Apparently LMT uses semi-auto carriers and carbine weight buffers in their commercial rifles, not sure if that's a detriment or not. I know KAC is also looked highly upon in general, but I'm not interested in the proprietary parts, not to mention they're not in stock anywhere.
My rule of thumb is what manufacturers' rifles hold up best in high round count classes and similar scenarios where they get run hard. I haven't been to carbine classes recently, if anyone has been able to make any observations at some, I'd appreciate any data as well as from any SME's that happen to see this thread.
Thank you.