Harrington Richardson Commando 300BLK 10.5″ Pistol – Rugged Retro 733-Style AR

Description

The Harrington Richardson Commando 300BLK is a 10.5-inch, 733-style retro AR pistol built by Harrington & Richardson, the historic name now revived by Palmetto State Armory for its line of period-correct AR clones. It pairs a dedicated .300 Blackout barrel with an M16A2-pattern lower, a C7-style upper and a slim adjustable blade, so it looks like an old Commando but feeds a cartridge built for short barrels.

Harrington Richardson Commando 300BLK Overview

5-inch tube. 300 Blackout instead. That round was designed to burn efficiently in short barrels and to run through standard AR magazines, so the gun keeps its classic Commando profile while delivering a heavier 110 to 125 grain bullet at useful velocity inside 200 yards. 56 build. Barrel construction is 4150 chrome moly vanadium steel with a Parkerized finish and a 1:8 twist, which stabilizes common supersonic loads and most heavy subsonic projectiles. 30 caliber pitch, and wears an A2-style flash hider.

Retro Styling With a Practical Cartridge

The upper is a C7-style receiver with feed ramps, combining the fixed carry handle and A2 rear sight with brass deflector and forward assist. Up front you get a rifle-height front sight base, the round six-hole carbine handguard and a pistol-length gas system. The bolt carrier is a full-auto profile unit with a Carpenter 158 steel bolt, and the trigger is a standard mil-spec group with the usual gritty but predictable pull.

Nothing here is exotic, which is the point: replacement parts are cheap and easy to find, and the whole package should feel familiar to anyone who has handled an issued M16A2 or early carbine.

The HAR-15 Blade and Pistol Configuration

In place of a stock, the buffer tube carries the H&R HAR-15 adjustable blade, a pistol stabilizing brace shaped to echo the old CAR-15 sliding stock. Regulation of braces has changed several times in recent years, and the 2023 ATF brace rule was vacated by a federal court in 2024, but the area remains active. 5-inch barrel unless you have an approved ATF Form 1 or Form 4, because that would create a short-barreled rifle regulated under the NFA.

Weight as configured is about 6 pounds, so it is a big handgun on paper and is best run from a sling.

Shooting the .300 Blackout

Supersonic 110 to 125 grain loads are the everyday choice here and should cycle reliably through the pistol-length gas system. Heavy subsonic ammunition is quieter and is the reason many people buy a Blackout, but it only delivers that benefit through a suppressor, and suppressors are NFA items that require an approved ATF Form 4 and state legality. Some subsonic loads may not cycle a pistol gas system unsuppressed. Expect more muzzle blast than a 16-inch rifle, and expect ammunition to cost noticeably more per round than bulk 5.56 or 9mm.

Safety Note on Mixed Magazines

The .300 Blackout feeds from ordinary AR-15 magazines, which is convenient but creates a well-known hazard. A .300 Blackout round can chamber in a 5.56 rifle and fire with catastrophic results. If you own both calibers, mark your Blackout magazines clearly, store ammunition separately, and never mix them in the same range bag. The dedicated roll mark on this lower helps, but it is not a substitute for good habits.

Optics and Upgrades

The fixed carry handle limits optic choices. A carry-handle mount will hold a red dot, but it sits high above the bore, so many owners simply enjoy the A2 irons as designed. Because the barrel is not chrome lined, clean it after shooting corrosive surplus or in wet weather. The six-hole handguard gets warm during fast strings, so a simple glove is worth packing for training classes.

State Laws and Ownership

AR-style pistols are restricted or banned in several states, including California, New York, New Jersey, Connecticut, Maryland, Massachusetts, Illinois and Washington, and some states also limit magazine capacity to 10 or 15 rounds. Local rules on braced pistols, threaded barrels and carry can differ from state rules, so confirm what applies where you live before ordering. Your receiving dealer can refuse a transfer that does not comply.

Specifications

• Manufacturer: Harrington & Richardson (Palmetto State Armory)
• Model: Commando 733-style pistol, PSA SKU HR51655203194
• UPC: 810141222687
• Caliber: .300 Blackout
• Barrel: 10.5 inch 4150 CMV, Parkerized, not chrome lined
• Twist: 1:8
• Muzzle: 5/8×24 thread with A2-style flash hider
• Gas system: pistol length, rifle-height front sight base
• Upper: C7-style with feed ramps and carry handle
• Lower: forged 7075-T6, M16A2 pattern, marked 300BLK
• Handguard: carbine six-hole round
• Bolt carrier: full-auto profile, Carpenter 158 bolt
• Trigger: mil-spec single stage
• Brace: H&R HAR-15 adjustable blade on carbine tube
• Weight: about 6 lb as configured
• Magazine: one 30-round AR-15 magazine (per distributor listing)

Before You Buy

Federal law requires that handguns, including AR-style pistols, be transferred through a licensed dealer to buyers 21 or older who pass a background check. Check your state rules on AR pistols, braces and magazine capacity, and budget for .300 Blackout ammunition, which costs more than 5.56.

Who It Is For

The Harrington Richardson Commando 300BLK is a great fit for collectors of retro AR clones who want a Commando look in a cartridge that actually suits a short barrel, and shooters planning a future suppressor host.

Buy the Harrington Richardson Commando 300BLK at MAG5 Firearms

MAG5 Firearms is a family-owned FFL in Collegeville, Pennsylvania. Order the Harrington Richardson Commando 300BLK online and ship it to your local FFL dealer, or browse our full selection of firearms for more pistols. For factory details, visit Harrington & Richardson.