Contemplating a New Build, Receiver Sets?

[Rifleman_04]

BCM still has those $50 blem upper receivers. I got one and it came assembled and a very small almost unnoticeable scratch on it.

I snagged two of those and couldn’t see any blem.

One was fine but the other wouldn’t allow any empty magazine to seat even with the bolt locked to the rear on any lower I tried including Colt and LMT lowers.

Blem isn’t always cosmetic I guess.