Thanks for a great explanation marine6680!
Well, I guess I have a lot to learn. For some reason, I thought BCM test fired every assembled rifle as well as check for a tight fit. I found that dealers and distributors do not test fire the rifles they assemble nor do they disclose they are assembling the rifle configuration that may be listed on their website or on GunBroker. Which by the sounds of it is no big deal....
Also, I found a video made a couple of years ago with Larry Vickers interviewing Paul Buffoni and at the 3:15 mark it shows the uppers being test fired.
https://youtu.be/JPLRUZbK_6I
So I wonder if some of BCM vendors are better than others on trying to find a tight fit? Any recommendations on BCM vendor list?
http://bravocompanymfg.com/support/where_to_buy.php