Davidson Defense Ronin Competition 18-inch Rifle-Gas 1:7.5 6mm ARC AR-15 Freefloat ML Handguard Rifle Full Build Kit

Ronin Competition 18-inch Rifle-Gas 1:7.5 6mm ARC AR-15 Freefloat M-LOK Rifle Full Build Kit

The Ronin Competition is a 6mm ARC AR-15 Full Build Kit built around an 18-inch rifle-length gas platform. The kit centers on an 18-inch government profile 41V50 CrMoV steel barrel with a nitride finish, 5R rifling, 1:7.5 twist rate, and 5/8x24 thread pitch, paired with a GI birdcage flash hider and a black crush washer. A micro low-profile steel gas block at 0.750 diameter and a rifle-length stainless steel gas tube are included on the front end. The USA-made slick side billet aluminum upper receiver features an anti-rotation cutout, paired with a 15-inch ACE Series freefloat M-LOK handguard in black. A complete 6.5 Grendel II bolt carrier group with QPQ nitride finish and a Mil-Spec M4 charging handle complete the upper side. The lower hardware includes a complete Mil-Spec AR-15 lower parts kit, a Mil-Spec heavy-duty 6-position aluminum carbine buffer tube, a standard 3 oz carbine buffer, a standard carbine recoil spring, a Mil-Spec M16 end plate, and a Mil-Spec AR-15 castle nut. The Special Operations adjustable AR-15 stock rounds out the kit. Lower receiver not included.

Key Features

• 18-inch government profile 41V50 CrMoV steel barrel, nitride finish, 5R rifling, 1:7.5 twist, 5/8x24 thread pitch, 6mm ARC
• Rifle-length gas system
• Rifle-length stainless steel gas tube
• Micro low-profile steel gas block, 0.750
• GI birdcage flash hider, 5/8x24, black crush washer included
• USA-made slick side billet aluminum upper receiver, anti-rotation cutout
• 15-inch ACE Series freefloat M-LOK handguard, black
• Complete 6.5 Grendel II bolt carrier group, QPQ nitride finish
• Mil-Spec M4 charging handle
• Complete Mil-Spec AR-15 lower parts kit
• Mil-Spec heavy-duty 6-position aluminum carbine buffer tube
• Standard carbine buffer, 3 oz
• Standard carbine recoil spring
• Mil-Spec M16 end plate
• Mil-Spec AR-15 castle nut
• Special Operations adjustable AR-15 stock

Perfect For

• Builders sourcing a complete 6mm ARC AR-15 full build kit with an 18-inch 41V50 CrMoV nitride barrel with 5R rifling, USA-made slick side billet upper with anti-rotation cutout, 6.5 Grendel II QPQ nitride BCG, 15-inch ACE Series freefloat M-LOK handguard, and Special Operations adjustable stock already included, pairing it with their own lower receiver
• Shooters building an 18-inch rifle-gas 6mm ARC platform who want the 6.5 Grendel II BCG, charging handle, complete lower parts kit, and Special Operations adjustable stock covered in one kit with a USA-made slick side billet upper and 5R rifled nitride barrel
• AR-15 builders who want a 6mm ARC full build kit with a 5R rifled 41V50 CrMoV nitride barrel, USA-made slick side billet upper with anti-rotation cutout, and a Special Operations adjustable stock without sourcing components separately

Barrel and Muzzle Device

The 18-inch government profile barrel is chambered in 6mm ARC and constructed from 41V50 CrMoV steel with a nitride finish and 5R rifling. The twist rate is 1:7.5 and the thread pitch is 5/8x24, which matches the included GI birdcage flash hider. A black crush washer, a micro low-profile steel gas block at 0.750 diameter, and a rifle-length stainless steel gas tube cover the front end gas configuration on this rifle-length platform.

Upper Receiver and Handguard

The USA-made slick side billet aluminum upper receiver features an anti-rotation cutout and removes the forward assist housing from the upper receiver body for a clean exterior profile. The 15-inch ACE Series freefloat M-LOK handguard is black with M-LOK attachment points along the body for accessory mounting. These two components define the exterior structure of the upper assembly on this AR-15 platform.

Bolt Carrier Group and Charging Handle

The complete 6.5 Grendel II bolt carrier group carries a QPQ nitride finish and is compatible with the 6mm ARC platform. A Mil-Spec M4 charging handle is included to complete the upper component set.

Lower Parts Kit and Buffer System

The complete Mil-Spec AR-15 lower parts kit covers the internal lower receiver components. The buffer system includes a Mil-Spec heavy-duty 6-position aluminum carbine buffer tube, a standard 3 oz carbine buffer, a standard carbine recoil spring, a Mil-Spec M16 end plate, and a Mil-Spec AR-15 castle nut. The Special Operations adjustable AR-15 stock pairs with the included Mil-Spec carbine buffer tube and covers the rear stock interface for this build.

Follow safe handling and manufacturer instructions. Ensure compliance with all applicable federal, state, and local laws. Lower receiver not included. Verify compatibility with your specific 6mm ARC lower receiver before use.