02-02-2022, 12:32 PM
When ever possible, I've gone to BCM and their "scratch and dent sale" for uppers. THey are a good, tight fit. On some, I've had to freeze the barrel and heat the receiver ( carefully !!! ) to get them together. BUT, when everything returns to room temp, it is a SOLID lockup. Some, I could just get started and then used the barrelt nut to pull 'em on in. Still, a very tight fit. Also, I have not yet seen a BCM upper receiver that needed to be trued, but i"ve not seen any other supplier that wasn't a little off. If you can find it, there was an article in G&A by Patrick Sweeney about accurizing AR's and he states that he was amazed at the difference truing up a receiver made. Note, this only applies to forged receivers, billet will start off good ( just not as strong ).