Rock River Arms BLK2142 LAR-15M RRAGE 300 AAC Blackout 30+1 10.50″ Black Threaded Barrel, M-LOK Handguard, Black Aluminum Picatinny Rail Receiver, Black Polymer SB Tactical SBA3 Brace, Black A2 Grip

The Rock River Arms BLK2142 LAR-15M RRAGE in 300 AAC Blackout is a purpose-built tactical pistol that delivers subsonic and supersonic performance from a compact 10.50-inch platform. Chambered in 300 AAC Blackout with a 30+1 magazine capacity, this rifle features a black threaded barrel for suppressor attachment, a low-profile gas block, a 7.25-inch M-LOK free-float handguard, and a SB Tactical SBA3 pistol brace. The black aluminum Picatinny receiver and A2 grip complete the package. At $1155.48, this Rock River Arms BLK2142 LAR-15M RRAGE 300 AAC Blackout 30+1 10.50-inch black threaded barrel, M-LOK handguard, black aluminum Picatinny rail receiver, black polymer SB Tactical SBA3 brace, black A2 grip is ready for duty.

Manufacturer	Rock River Arms
Model	BLK2142 LAR-15M RRAGE
Material	Black Aluminum (receiver), Black Polymer (brace/grip), Steel (barrel)
Compatibility	300 AAC Blackout ammunition, AR-15 lower parts (per manufacturer specs)
Finish	Black anodized aluminum, black polymer, black oxide barrel
Weight	Approximately 6.2 lbs (unloaded, per manufacturer specs)
Condition	New

Key Features

• 10.50-inch Threaded Barrel: Why it matters – This length optimizes 300 AAC Blackout ballistics for both subsonic and supersonic loads, and the 1:8 twist stabilizes heavy match bullets. The threaded muzzle (5/8×24) accepts suppressors or an A2 flash hider directly.
• SB Tactical SBA3 Adjustable Brace: Why it matters – The SBA3 uses a carbine buffer tube and provides a stable, adjustable cheek weld for rapid target transitions while staying legally compliant as a pistol brace. It collapses and extends without tools.
• 7.25-inch M-LOK Free-Float Handguard: Why it matters – Free-floating eliminates barrel contact, preserving accuracy potential. M-LOK slots allow direct attachment of rails, bipods, and lights without adding weight or bulk.
• Low-Profile Gas Block: Why it matters – Keeps the handguard diameter slim and allows for suppressor clearance. The block is pinned to the barrel for positive gas seal and reliability under rapid fire.
• Single-Stage Trigger: Why it matters – A clean, consistent break at approximately 5.5 lbs aids speed without sacrificing precision. The single-stage design is predictable for defensive or competition use.

Who It’s For

This build targets shooters who want a compact 300 BLK pistol for home defense, truck gun, or suppressed plinking. If you run subsonic loads with a suppressor and need a reliable, accurate platform under 30 inches overall, the RRAGE fits. It also suits shooters who prefer a pistol brace over an SBR tax stamp, and want M-LOK compatibility for accessories.

Pros & Cons

• Pros: Factory-built reliability; 30+1 magazine capacity; SB Tactical brace included; threaded barrel accepts standard suppressors; M-LOK handguard for modularity.
• Cons: The single-stage trigger is not upgradeable without replacing the entire fire control group. Some shooters prefer a two-stage for precision work. Also, the 10.5-inch barrel produces more muzzle blast with supersonic loads compared to longer barrels.

Comparison vs. Competitors

Feature	Rock River Arms BLK2142	Zev Technologies OZ9C	Geissele Super Duty 10.3″
Caliber	300 AAC Blackout	9mm	5.56 NATO
Barrel Length	10.50″	4.5″	10.3″
Brace/Stock	SB Tactical SBA3	None (pistol frame)	B5 Systems (stock)
Handguard	7.25″ M-LOK	Integrated	12″ M-LOK
Trigger	Single-stage	Flat-face	Geissele SSA-E two-stage
MSRP	$1,155	$1,699	$1,899
Best For	Suppressed 300 BLK, home defense	Concealed carry, competition	Duty rifle, precision

FAQ

What is the twist rate on the barrel?

Per Rock River Arms specs, the barrel has a 1:8 twist, optimized for 300 AAC Blackout bullets from 110 to 220 grains.

Can I mount a suppressor directly?

Yes. The barrel is threaded 5/8×24. You can attach a direct-thread suppressor or use a muzzle device with compatible threading.

Is this considered a pistol or a rifle?

It ships as a pistol with an SB Tactical SBA3 brace, not a stock. Check your state laws before adding a vertical foregrip.

Does it come with a magazine?

Yes. One 30-round magazine is included, along with a manual and warranty info.

Last updated: April 2026. According to NSSF data, 300 AAC Blackout accounts for over 12% of AR-style pistol sales in the US, making this caliber a solid choice for compact builds.

✓ Nationwide delivery (all 50 states) ✓ Ships 1-2 business days ✓ 30-day returns ✓ Secure checkout

Browse more in 300 Blackout Pistols or AR-15 Pistols.