SOFR Precision Upper 18” 6mm ARC

Description

Uppers are Built within 2-4 Business Days after Ordering. You will receive tracking information when the Upper is shipped.

Overt Industries SOFR Precision Upper - 18" 6MM ARC - Suppressor Dedicated

Overt Industries 18" 6MM ARC 416R Stainless Steel - 1/7.5 with 3R Rifling - Suppressor Dedicated Barrel
Overt Industries Upper Receiver
Overt Industries Nitrided Steel Gas Block & SS Rifle+1 Length Gas Tube
Overt Industries 15" Hard-Line MLOK® Rail System

Overt Industries Reliability: Overt Industries is known for its commitment to quality and innovation. We 100% QC every SOB barrel and ensure that the gas port diameter is within 0.001" of our specification of 0.078". Our suppressor-optimized barrel is no exception, embodying our Hard Use - Zero Sacrifice Ethos.

Assembly Process

This Upper Receiver assembly was properly assembled using Aeroshell 64 on the barrel extension and barrel nut after the threads were properly seasoned. The barrel was also properly dimpled using a BRD Engineering Pro Jig and the gas block set screws were tightened using Rocksett for maximum reliability at high temperatures. The handguard was assembled using Loctite 242 on the rail mounting bolts.

Component Specifications (Please Read)

Precision Series Barrel Specifications

Built from 416R stainless steel and chambered in 6MM Arc, this Precision Series barrel features advanced 3R rifling and a rifle+1 length gas system engineered for dedicated suppressed use. Designed to deliver supreme precision, it offers 1 MOA guarantee with quality match ammunition. The Suppressor Dedicated gas port reduces felt recoil (allowing for easier shot spotting and follow up shots), reduces gas expelled to the shooter’s face - while improving reliability and component longevity by eliminating the harsh cycling associated with over-gassed systems.

Why 3R Rifling? 3-groove (3R) rifling is designed to enhance performance and longevity, offering increased barrel life, improved velocity, and reduced cleaning requirements. Its fewer, wider lands and grooves minimize bullet deformation and fouling, while the odd number of grooves helps distribute stress more evenly on the projectile—often resulting in improved accuracy, particularly in high-velocity applications.

Gas Port Diameter = 0.078

Unlike other companies, we publicly disclose our gas port diameter so you, the end user knows exactly what they are purchasing. As shooters, we were frustrated when companies refused to disclose their gas port diameters and we were left to purchase barrels hoping for a desired result.

Tuning your Buffer System:

Suppressor Dedicated: This barrel is designed for Suppressed use ONLY – We recommend starting a standard carbine buffer system with 3oz carbine buffer to confirm functionality with your specific application. To further tune your rifle’s performance, a Sprinco Blue Spring, H1/H2 Buffer,. Keep in mind that every suppressor has varying back-pressure and buffer system configuration may need to be slightly adjusted for your specific application. The use of the A5 Buffer System is possible when pairing with high back-pressure suppressors, although we have found the carbine buffer system to be very effective for this gas system.

Ammunition - We have tested our 6mm Precision Series Barrels with various commercial loads and confirmed perfect reliability, ranging from lighter 80gr ELD-VT (lower case pressure) to heavier 108gr ELD. Keep in mind that some of the lighter and lower case pressure loads will require the factory 3oz buffer and spring, but you can add buffer weight and spring tension with heavier and higher case pressure loads depending on your specific suppressor application.

We designed our Suppressor Dedicated Barrels for traditional baffle stack suppressors. The Suppressor Dedicated Series is compatible with the vast majority of "reduced back pressure suppressors", but we do not recommend pairing with true Flow-Through suppressors due to the drastic reduction in back pressure.

Our barrels include one gas block set screw dimple located directly under the gas port for enhanced durability and compatibility with industry standard gas blocks.

Length	18″
Weight	40 Oz
Material	416R Stainless Steel
Profile	Heavy Precision
Caliber	6mm ARC
Twist	1/7.5 - 3R Rifling
Muzzle Device Thread	5/8x24
Gas Block Journal	0.750"
Gas System	Rifle+1 Length
Crown	Recessed Target

Note this barrel is optimized for suppressor use and compatibility with the various ammunition on the commercial market. Some ammunition does vary in case pressure, so we always recommend testing prior to purchasing ammunition in bulk.

Overt Industries AR-15 Hard-Line MLOK® Rail System

The Hard-Line MLOK® Rail System was designed with an emphasis on Rigidity, Ruggedness, and Simplicity. 100% Made in the USA, the Hard-Line MLOK® Rail System utilizes a Three Point Mounting System to ensure that the handguard clamps securely to the barrel nut without the possibility of unwanted rotation.

Machined from American sourced 7075 T-6 extruded aluminum, the Hard-Line MLOK® Rail System offers increased strength, rigidity and reduces overall handguard flex by removing often unused MLOK® sections in order to enhance the structure of the rail system. The increase in handguard rigidity reduces handguard flex resulting in a stronger mounting structure for Laser Aiming Devices. We also integrated chamfered serrations to the exterior of the rail system in order to provide maximum grip friction to the end user.

Features: