Details
Ronin Competition Left-Handed 16.5-Inch Mid-Gas 1:7 5.56 NATO AR-15 Free-Float M-LOK Handguard Rifle Upper Build Kit
The Ronin Competition Upper Build Kit is built around a 16.5-inch 5.56 NATO barrel machined from 4150 chrome moly vanadium steel in a medium profile, with a mid-length gas system and a Nitride finish. It is paired with a left-handed Black Diamond Series slick-side billet upper receiver and a 15-inch ACE Series free-float M-LOK handguard in black. The left-handed receiver is built for left-side-ejecting configurations, and the slick-side design leaves the receiver sides clean and uncluttered. The medium profile balances weight and stiffness at the front of the rifle, and the 1:7 twist suits a wide range of bullet weights in 5.56 NATO. BCG and charging handle are not included.
Key Features
- 16.5-inch medium profile barrel, 4150 chrome moly vanadium steel, Nitride finish, 1:7 twist, 5.56x45mm NATO
- Mid-length gas system with a micro low-profile steel gas block sized for a .750-inch barrel
- Left-handed Black Diamond Series slick-side billet upper receiver, 6061-T6 aluminum, anodized finish
- 15-inch ACE Series free-float M-LOK handguard, 6061-T6 aluminum, black
- AR-15 A2 GI birdcage flash hider, Manganese Phosphate finish, on 1/2x28 threads with 1/2-inch black crush washer
- BCG and charging handle are not included.
Barrel and Gas System
The 16.5-inch barrel is machined from 4150 chrome moly vanadium steel in a medium profile and finished in Nitride, a surface treatment that adds hardness and corrosion resistance while leaving a clean, matte black look. Its 1:7 twist rate is suited to a wide range of bullet weights in 5.56 NATO. The barrel runs a mid-length gas system through a micro low-profile steel gas block sized for the .750-inch barrel diameter, and the low-profile block helps it sit cleanly beneath a free-float handguard. At the muzzle, 1/2x28 threads carry the included AR-15 A2 GI birdcage flash hider, finished in Manganese Phosphate and secured with the supplied 1/2-inch black crush washer.
Upper Receiver and Handguard
The upper receiver is a left-handed Black Diamond Series slick-side billet unit machined from 6061-T6 aluminum and finished in anodizing, a hard, wear-resistant surface that holds up to regular handling. It is paired with a 15-inch ACE Series free-float M-LOK handguard machined from 6061-T6 aluminum and finished in black. As a free-float design, it leaves the barrel free of handguard contact, and the M-LOK slots give the builder room to mount lights, grips, handstops, and other accessories.
Compatibility
This kit is built for AR-15 lower receivers chambered in 5.56 NATO. A left-handed bolt carrier group is required to match the left-handed upper, and it is not included. Gas tube details, forward assist and ejection port door configuration, and handguard attachment hardware were not supplied with this listing and should be confirmed before purchase. Because the BCG and charging handle are not included, they must be sourced separately to complete the upper.
Follow all manufacturer instructions and safe handling practices.
Ensure compliance with all applicable federal, state, and local laws.
