BCM Blem Upper Receiver Is In Stock

[montana]

The inside diameter of the receiver extension is undersized. I.e., out of spec. They say so on their website.

Here is what is stated: Inside Diameter for barrel extension slightly undersized for a tighter fit to the barrel and a more accurate rifle. Please use a heat gun or hair dryer to warm up threaded bore of receiver if barrel extension is too tight.) The BCG channel is also smaller for a tighter and straighter fit..

So in your assessment, "a part that is highly manufactured to perform better" is out of spec if it doesn't meet the sloppy fit of +- mil spec TDP. OK, I'll give that to you. JP parts are also out of spec.

I just want others to understand it is better than mil spec, not a gimmick or for cultist as you have ascertained...

Carry on...