The Rock River Arms LAR-15M All Terrain Hunter is a semi-automatic rifle chambered in .450 Bushmaster, built on an AR-15 platform with a 16-inch barrel. The .450 Bushmaster makes it legal for straight-wall cartridge states and capable of taking deer and larger game at reasonable distances. 
 

Key Specifications 

• Model: LAR-15M All Terrain Hunter 
• Caliber: .450 Bushmaster 
• Action: Semi-Auto 
• Barrel Length: 16 inches 
• Capacity: 5+1 rounds 
• Trigger: RRA Two-Stage Ultra Match 
• Safety: Safety Selector Switch 
• Overall Length (OAL): 34.50 inches 
• Weight: 6.80 lbs 
• Stock Description: Adjustable RRA Operator CAR 
• Sights: Optic Ready 
• Barrel Twist Rate: 1:24 inches 
   

Detailed Features 

 
The RRA Two-Stage Ultra Match trigger has a distinct first stage take-up followed by a clean second-stage break. It's a noticeably better trigger than a standard mil-spec single-stage, and it makes a practical difference for hunting shots where you're waiting on your target. 
 
The RRA Operator muzzle brake manages .450 Bushmaster recoil well — the cartridge can push hard in a 6.80 lb rifle, and the brake makes follow-up shots less punishing. The adjustable Operator CAR stock takes the rifle from 34.5 inches up several positions to fit larger shooters. 
 
Barrel twist is 1:24, optimized for the heavy, large-diameter projectiles .450 Bushmaster uses. The optic-ready flat-top receiver accepts any standard AR-compatible scope mount. 
 

Usage Scenarios 

 
This rifle is primarily a hunting platform — the .450 Bushmaster covers whitetail and larger game, and the straight-wall cartridge qualifies in states with those regulations. It also works as a range rifle for shooters who like the AR platform in a big-bore configuration.

The RRA LAR-15M in .450 Bushmaster is well-regarded among hunters who need a straight-wall rifle, and the feedback reflects that focus. The RRA Two-Stage Ultra Match trigger gets specific praise — users find the break cleaner and more consistent than the mil-spec triggers on comparable rifles, which matters when you're holding for a clean shot.

Build quality gets positive marks consistently. RRA's machining standards are recognized, and the all-terrain designation holds up in practice — the rifle handles weather and field conditions without complaints.

Recoil from .450 Bushmaster is real, and a few users note that the muzzle brake is necessary rather than optional at this power level. The weight at 6.80 lbs is considered reasonable, though some find it a bit heavy for all-day carries.

The 5+1 capacity is a straightforward trade-off of the larger cartridge on an AR platform — most hunting applications don't need more. Pricing comes up as a consideration; some buyers compare RRA to less expensive options, while others feel the trigger quality alone justifies the cost.

Overall, the sentiment among owners is positive, especially from hunters who prioritize trigger feel and reliability in a straight-wall hunting carbine.