LANTAC USR FORGED UPPER RECEIVER BLK

Description

The Lantac USR Upper Standard Receiver is aimed at builders who want a stripped upper machined to tighter internal geometry than a standard mil-spec forging allows. The bore of this receiver is finished to a roughness average of 16 microinches — roughly half the surface roughness of a conventionally bored or milled upper, which typically runs between 32 and 63 microinches. That smoother bore surface reduces friction along the full travel of the bolt carrier, translating directly into a slicker cycling feel and less wear at the contact points over time.

Lantac machines the barrel nut threads, receiver bore, and barrel extension seating surface in a single operation. Running those cuts without re-chucking the workpiece keeps them concentric and perpendicular to one another, which means a barrel installed into this upper sits in proper alignment without relying on the assembler to dial out any off-axis deviation. That geometric accuracy matters for headspace consistency and long-term barrel fit.

Construction is 7075-T6 aluminum, the same alloy grade used in mil-spec receivers, finished in a Milspec Type III, Class 2 deep black hardcoat anodize. Type III hardcoat is the harder of the two common anodize grades and holds up better to the kind of abrasive contact an upper sees from repeated assembly and disassembly cycles. M4 feed ramps are cut as standard, providing the extended ramp geometry that aids reliable feeding in a wide range of ammunition profiles. Stripped weight is 7.0 oz. The receiver is manufactured in the United States by Lantac USA.