Mass production usually comes at a price. In this case this AR15 forged upper receiver has been manufactured in such a way that the barrel extension boss is out of alignment with the bore. We cut the bore and barrel extension boss on our upper receivers in one operation so that we guarantee concentricity and perpendicularity, meaning the barrel sits properly in the upper receiver and aligns with the Bolt Carrier Group perfectly.
This upper that was purchased by the customer from another company had to be trued before assembly. Unfortunately most gun shops and gun assemblers don't have the ability or knowledge to do this.
