Description
The Rock River Arms LAR-BT3 X-1 308 Win is a billet large frame AR built for accuracy and guaranteed to 1 MOA at 100 yards. An 18 inch cryogenically treated fluted stainless barrel, a 17 inch free float M-LOK rail and a two stage Ultra Match varmint trigger are what get it there.
Billet Receivers and a Match Barrel
Both receivers are RRA’s own LAR-BT3 billet units rather than forgings, machined to fit each other more precisely than a standard mil-spec pairing. On a rifle sold with an accuracy guarantee, that fit matters as much as the barrel does.
The barrel is 18 inches of fluted stainless with a 1:10 twist, cryogenically treated to relieve machining stress. Cryo treatment is why a barrel this light holds its point of impact through a string of shots instead of walking as it heats.
Rock River Arms LAR-BT3 X-1 308 Trigger and Gas System
The trigger is RRA’s two stage Ultra Match varmint unit, which takes up cleanly and breaks without creep. It is the same trigger Rock River puts in its dedicated varmint rifles and is a large part of why the accuracy guarantee is realistic rather than marketing.
A low profile gas block runs a mid-length gas system, which is the right length for an 18 inch .308 barrel. Mid-length spreads the pressure curve out and reduces bolt velocity, so the rifle runs softer and the parts last longer.
Handguard, Muzzle and Furniture
The handguard is RRA’s 17 inch lightweight free float rail with M-LOK slots, which runs almost to the muzzle brake and leaves room to mount a bipod well forward for stability. Nothing you attach touches the barrel.
An RRA Hunter muzzle brake sits on 5/8-24 threads. The stock is the RRA Operator CAR six position unit and the grip is Hogue rubber, both chosen for shooting from field positions rather than only from a bench.
Specifications
- Manufacturer: Rock River Arms
- Model: LAR-BT3 X-Series X-1
- Item Number: XBT31751B.V1
- Caliber: .308 Win. / 7.62×51 NATO chamber
- Action: Direct impingement semi-automatic
- Capacity: 20+1
- Barrel: 18 in. fluted stainless, 1:10 twist, cryogenically treated
- Muzzle device: RRA Hunter brake, 5/8-24
- Gas system: Mid-length with low profile gas block
- Trigger: RRA two stage Ultra Match varmint
- Handguard: RRA 17 in. lightweight free float M-LOK
- Receivers: RRA LAR-BT3 billet upper and lower
- Stock: RRA Operator CAR, six position
- Grip: Hogue rubber
- Weight: 9.5 lbs.
- Overall length: 40.5 in.
- Accuracy: 1 MOA at 100 yards
- Includes: One magazine, case, extended charging handle latch, manual and warranty
- UPC: 842834108435
Ammunition and Range
Match loads in 168 and 175 grain are where a 1:10 twist .308 does its best work, and an 18 inch barrel gives up very little to a 20 inch one. For hunting, 150 to 165 grain soft points cover deer, hog and black bear comfortably inside 300 yards.
Why Buyers Choose the Rock River Arms LAR-BT3 X-1 308
The Rock River Arms LAR-BT3 X-1 308 arrives finished. Billet receivers, a cryo treated match barrel, a two stage trigger and a 17 inch free float rail are all already on the gun, and it ships in a case with an accuracy guarantee behind it.
Who Should Buy It
Precision shooters who want a semi-automatic, hunters after deer and hog with a fast second shot, and anyone who would otherwise buy a base AR-10 and spend the difference upgrading it.
Be realistic about the trade-offs. Nine and a half pounds before optics is real weight, .308 ammunition costs more than 5.56, and no optic, rings or bases are included. The muzzle brake is effective and correspondingly loud beside you.
Full factory specifications are published by Rock River Arms. Compare the rest of the RRA line in our firearms selection.
Every firearm we list ships to your chosen FFL and is transferred there after a background check.
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