Ruger AR-556 MPR 450 Bushmaster 18.63″ 5+1

Ruger AR‑556 MPR (.450 Bushmaster, 18.63″ Barrel, 5+1)

Specifications

• Caliber: .450 Bushmaster (9.48 mm / .452″)
• Barrel: 18.63″ cold-hammer-forged 4140 chrome-moly with 5R rifling, 1:16 twist, threaded 11/16″–24 and equipped with Ruger’s radial-port muzzle brake
• Gas System: Carbine-length direct impingement
• Receiver & Handguard: Forged 7075-T6 upper, free-float 15″ M-LOK handguard with full-length Picatinny
• Stock & Grip: Magpul six-position MOE SL stock + pistol grip
• Bolt: Super-alloy bolt with tapered lugs for .450 case head
• Trigger: Ruger Elite 452 two-stage trigger (~4.5 lb)
• Capacity: 5+1 with included steel magazine; can fit ~8 rnd in a 20-rd GI mag
• Weight: ~7.4 lb empty; overall length adjustable from ~35.6″–38.9″; LOP 11.1″–14.4″
• Finish: Type III hard-coat anodized receiver and nitride barrel

Performance & Use

• Recoil & Handling: Despite powerful recoil energy (~22 ft‑lb, akin to 7mm Magnum), the brake and weight make it manageable .
• Accuracy: Typically 3–4 MOA with factory ammo; sub-MOA possible with premium rounds and bench rest (e.g., .837″ at 65 yd) .
• Reliable Feed & Function: Tested flawlessly with steel-cased and brass commercial .450 Bushmaster rounds; bolt carrier functions like AR-15 variants but with reinforced bolt/lug design
• Effective Hunting Cartridge: Ideal for medium game (hogs, deer) inside ~200 yd; some states legal for straight-wall cartridges in shotgun seasons.

Highlights & Advantages

• Big-Bore Power: Delivers .45‑70 level energy with AR platform convenience
• Built Rugged: Quality bolt upgrades and robust construction built for the larger cartridge .
• Recoil Mitigation: Effective brake and weight help control heavy-kicking rounds .
• Accessory Ready: Full-length rails for optics; suppressor-ready barrel threading