First Look: Rock River Arms LAR-15M in .450 Bushmaster

posted on March 19, 2020

Rock River Arms recently introduced an AR-15-based carbine chambered in .450 Bushmaster. Developed as a modern sporting firearm, this new entry into RRA's LAR lineup brings dominating short- to mid-range capabilities to America’s shooting enthusiasts.

The RRA LAR-15M .450 Bushmaster brings a new dimension in firepower for modern shooters who prefer to use straight-wall cartridges. Delivering the same 1 MOA at 100 yards accuracy expected from RRA's precision rifles, the .450 Bushmaster has a 16-inch stainless-steel cryo-treated barrel with smooth rifling (1:24-inch twist) and is equipped with an RRA Operator Brake. The RRA two-stage trigger provides a crisp break and is housed inside a RRA winter trigger guard, allowing full dexterity in the field while wearing gloves.

The RRA LAR-15M .450 Bushmaster comes equipped with a six-position Operator CAR stock, an over-molded A2 pistol grip, and a 13-inch extended lightweight free-float handguard that covers a low-profile gas block and a mid-length gas system. The full-length Picatinny top rail allows you to mount the optic system of your choice, while the M-Lok handguard allows for the easy attachment of accessories such as a bipod, a light source or a forward grip. The rifle also includes a sturdy hard plastic, five-round polymer magazine, owner’s manual and warranty.


  • Caliber: .450 Bushmaster
  • Lower Receiver: Forged RRA LAR-15M Multi-Caliber marked
  • Upper Receiver: Forged A4
  • Barrel: 16-Inch Cryo-Treated stainless, 1:24-inch twist, 5/8-32 tpi thread
  • Muzzle: RRA Operator brake
  • Gas Block: Low-Profile gas block, mid-length gas system
  • Trigger: RRA Two-Stage / RRA Winter triggerguard
  • Safety: RRA standard
  • Handguard: RRA 13-Inch lightweight, freefloat, M-Lok compatible
  • Buttstock: RRA Operator CAR stock
  • Pistol Grip: RRA overmolded A2 grip
  • Weight (w/empty magazine): 6 pounds, 13 ounces
  • Length: 37.5-Inches extended
  • Includes: One magazine, RRA case, manual, and RRA limited lifetime warranty


MSRP on the RRA LAR-15M .450 Bushmaster is $1,100, and more information is available at


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