The USR™ Upper Standard Receiver is a precision machined upper with a special proprietary bore that is ultra smooth with a roughness average in micro inches of 16, as opposed to standard bored or milled uppers that are 32-63, or higher.  This reduces bolt carrier friction and creates a much smoother operation. Barrel nut threads, bore and barrel extension surfaces are all machined in one operation so that they are perfectly concentric and perpendicular to the barrel and fixing assembly.

Specification:

• Material: Billet 7075-T6 Aluminum
• Finish: Milspec Type3, Class2 Deep Black Hardcoat Anodize.
• Super smooth Bore.
• M4 Feedramps as standard.
• Made in the USA.
• Stripped Weight 7.0oz (197g).

ITAR Notice:
This product is manufactured in the USA by LANTAC USA LLC for sale within the USA only.
Export of the commodities described herein is strictly prohibited without a valid export license issued by the U.S. Department of State, Office of Defense Trade Controls, prescribed in the International Traffic in Arms Regulation (ITAR), Title 22, Code of Federal Regulations, Parts 120-130.