Upper Receiver Question

[Rascally]

BCM mentions that the barrel extension is slightly smaller to give a tighter barrel to receiver fit, for better accuracy with their receiver (BCM4-UR-M4). Does BCM also square (lap) the front of the barrel extension for the same purpose? If not, will they do it upon request with a purchase of said receiver?

[markm]

You mean where the carrier hits?

[Slippers]

You mean where the carrier hits?

I think he means the front of the receiver, where the barrel extension flange sits between the receiver and the barrel nut. I highly doubt they lap it before they anodize it, but since BCM is cutting the receiver forging instead of sourcing it out, it's pretty safe to say it's going to be flat and concentric with the bore.

[markm]

Yeah... I've heard of truing up the receiver, but never the extension.

[Rascally]

In lieu of knowing the actual name for it, I was trying to use their (BCM) own terminology at http://www.bravocompanyusa.com/BCM-Upper-Receiver-assembly-M4-Flat-Top-p/bcm4-ur-m4.htm wherein they say "(Inside Diameter for barrel extension slightly undersized for a tighter fit to the barrel and a more accurate rifle.)" If it's incorrect then I guess I apologize for using the wrong phrase. Now...I wonder if I could maybe get an answer? I would prefer to try to know for sure before spending the money.

Thank you for any answers.

[Iraqgunz]

No they will not do custom stuff like that and I don't think its needed.

[Rascally]

Thank you for your time to answer, Iraqguns. I guess my search continues.