Rock River Arms LAR-BT9G CAR A4 — 9mm Luger, 16" Threaded Barrel, Black — Aluminum Receiver, RRA 6-Position Tactical Carbine Stock, Hogue® Rubber Grip, Right-Hand (BT91850 | UPC 842834125203)
A pistol-caliber carbine that feels like your favorite AR. The Rock River Arms LAR-BT9G CAR A4 delivers dependable 9mm Luger performance in a familiar AR-15 style package with a 16" threaded barrel, rugged black aluminum receiver set, an adjustable RRA 6-Position Tactical Carbine Stock, and a grippy Hogue® rubber pistol grip. Purpose-built for training, PCC competition, home defense, and range use, model BT91850 runs soft, points fast, and accepts common AR-pattern accessories so you can set it up exactly how you shoot.
Why Choose the LAR-BT9G CAR A4 9mm
Low Recoil, Fast Follow-Ups: 9×19 reduces muzzle rise and fatigue for tight splits and quicker transitions on steel or paper.
16" Threaded Barrel: Optimized for velocity and controllability; factory threading (verify pitch) supports brakes, comps, and suppressor mounts where legal.
AR-Style Controls: Familiar manual of arms streamlines training—great crossover for shooters who already run 5.56 carbines.
Adjustable Fit: The RRA 6-position stock dials in length of pull for body armor, layers, or different shooters.
Confident Grip: Hogue® rubber overmold provides traction in rain, sweat, or gloves for consistent trigger press and control.
Rock River Build Quality: Tight receiver fit, tuned system, and clean assembly for reliable cycling across popular 9mm loads.
Key Features & Specs
Model: LAR-BT9G CAR A4
Part Number: BT91850
UPC: 842834125203
Caliber: 9mm Luger (9×19)
Barrel: 16", threaded muzzle (verify thread pitch; commonly 1/2×28 or 1/2×36 for 9mm)
Receivers: Black aluminum upper & lower
Stock: RRA Tactical Carbine, 6-position adjustable, black polymer
Grip: Hogue® rubber overmold, black
Handguard: Free-float/rail style may vary by lot—M-LOK® ready on most current models*
Sights: Optic-ready; add irons or a red dot to preference
Orientation: Right-hand
Finish: Black throughout
Capacity: Accepts PCC magazines per configuration (verify pattern and included mags with retailer)
*Always confirm the current handguard pattern, trigger, and muzzle device with your retailer.
Performance You’ll Notice
Flatter Tracking Dot: Soft 9mm impulse helps you keep the reticle on target through strings and movement.
Tight Practical Accuracy: Free-float handguard + quality barrel support repeatable groups from 10 to 100 yards.
Economical Training: 9mm ammo stretches practice budgets while preserving AR-style handling and manipulation skills.
Ideal Use Cases
USPSA PCC / Steel: Light recoil, quick handling, and accessory flexibility for match day success.
Home Defense: Manageable blast and controllability with modern defensive 9mm loads; tailor with a light and red dot.
Range & Training: Perfect for carbine fundamentals, new shooters, and high-rep drills without centerfire rifle costs.
Ranch/Truck Gun: Durable finish and simple controls for everyday utility.
Smart Setup Ideas
Optics: Micro red dot for speed, or a compact 1× prism with etched reticle for daylight-bright precision.
Muzzle Device: Comp or brake to trim movement further; always re-zero after installation and verify thread pitch.
White Light & Sling: Mount a compact light at 3/9 o’clock; add a two-point QD sling for stability and transitions.
Magazines: Use quality PCC mags matched to your rifle’s mag interface; label and rotate to maintain spring health.
Best Practices (Non-Instructional)
Zero at 15–25 yards for typical PCC distances; confirm holds at 50–100 yards.
Ammo Testing: Try 115–147gr; many PCCs feel soft and shoot flat with 124–147gr.
Torque & Witness: Torque optic and M-LOK® hardware to spec; paint-pen witness marks simplify quick checks.
Keep It Lubed: PCC systems run best with a properly lubricated bolt/BCG, especially on long range days.
Care & Maintenance
Bore & Chamber: Clean carbon regularly; 9mm can be dirtier than .223.
Feed System: Inspect feed ramp and mags for debris; replace worn springs/followers as needed.
Hardware Audit: Re-verify optic, handguard, and muzzle-device fasteners after initial break-in.
Safety & Compliance
Know and follow all federal, state, and local laws regarding firearm features, magazine capacity, suppressor use, and transportation. Always verify the firearm is unloaded before maintenance or storage, and use proper eye/ear protection.
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Rock River Arms LAR-BT9G CAR A4 — 9mm Luger, 16" Threaded Barrel, Black Aluminum Receiver, RRA 6-Position Tactical Carbine Stock, Hogue Rubber Grip, Right-Hand (BT91850 | 842834125203): a soft-shooting, AR-familiar PCC that’s easy to control, easy to accessorize, and built for training, competition, and confident everyday carry-over to the range.
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