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OPTION DETAILS
GAS BLOCK: Standard or Adjustable. Adjustable is a great option if you are using a suppressor or just want to fine tune your system.
MUZZLE DEVICE: Standard A2 Flash Hider or Competition Muzzle Brake. Muzzle Brakes are for recoil reduction. The baffles and ports are milled larger to drive pressure up and to keep the muzzle down more effectively.


LEFT HAND Bolt Carrier Group: BCG is Optional. Select Nitride if you need a BCG to complete Upper . All our BCGs are M16 Profile, Properly Staked Gas Key, MP Tested, 8620 Carrier, 9310 Bolt. Nitride is a surface hardening process that creates a tough and slick surface.
Experience the versatile downrange performance of Hornady's advanced 6mm ARC cartridge, optimized completely for southpaw marksmen. The PRO2A Left Hand 16" 6mm ARC Mid-Length Non-Reciprocating (NR) Side Charging Upper Assembly delivers clean, efficient control. By coupling a mirrored left-eject port layout with an intuitive left-side charging handle, this upper keeps hot brass and escaping blowback gases completely out of your peripheral line of sight. The non-reciprocating cocking handle stays fully stationary during cycling, ensuring it never strikes bulky target optics or gear. Built around a standard compliance-friendly 16-inch barrel and tuned with a smooth mid-length gas system, this premium upper drops natively onto any Mil-Spec AR-15 lower receiver to anchor a highly precise, soft-recoiling distance setup. Proudly 100% designed, machined, and hand-assembled in the USA.
| Receiver | Gibbz Arms G4 LEFT HANDED Non Reciprocating Side Charging Billet Aluminum Receiver with Gen 2 Handle, M4 Feed Ramps, Type III Hardcoat Anodized Black |
|---|---|
| Barrel Material & Profile | 16 Inch Profile, 4150 Chrome Moly Vanadium Steel, Medium Profile Contour, Melonite Treated |
| Caliber | 6mm ARC (Advanced Rifle Cartridge) |
| Twist Rate | 1:7.5 Twist (Optimized for high-BC precision projectiles) |
| Gas Operating Block | Mid-Length System, Low-Profile Gas Block Machined from 4140 Steel, Stainless Steel Gas Tube |
| Muzzle Device Config | Standard 5/8-24 Thread Pitch, A2 Flash Hider with Crush Washer |
| Handguard | 12" Slim Profile Free-Float M-LOK Rail, Machined from 6061-T6 Aluminum |
| Manufacturing Origin | 100% Made in the USA with Pro2A Tactical Lifetime Factory Warranty |
Left-handed marksmen who want to match the low drop and high ballistic consistency of larger calibers while utilizing a lightweight, small-frame AR-15 platform rely on the 6mm ARC configuration for flat tournament strings.
Coyote, varmint, and medium-game hunters operating across wide clearings choose this layout. The left-eject mechanism guarantees that quick follow-up shots can be executed cleanly without unburnt powder or spent brass crossing the shooter's visual line of sight.
Shooters running bulky thermal scopes, night-vision frames, or wide low-power variable optics (LPVOs) prefer side-charging setups. The left-side charging handle clears the wide undersides of scope mounts, protecting knuckles from scrape damage.
| SKU | P2ALNR6ARCGAX12MID16-TK |
|---|---|
| Barrel Length | 16 inch |
| Rifle Caliber | 6mm ARC |
| Manufacturer | Pro2A Tactical |