I have two BCM builds and they are are of the utmost quality. I slapped a MOE handguard set on the 11.5" and it was tighter than on another build I made a while ago with a 16" barrel from a different manufacturer which had some wiggle. Both BCM's have been flawless with the BCM bolt carriers.
how much would it cost to build a BCM like that?
Looking at BCM's website, 16" midlength recce upper reciever group with DD handguard is running $895.00, but there are better options for handguards out there.
Example; DD lite 12" weighs 15.3 oz
VTAC Alpha 11" weighs 10.17 oz.
On the BCM 16" midlength Recce upper receiver group page they list an upper with the alpha handguard for $749.00
(See this link