Description
The Harrington Richardson 635 9mm Pistol is a 10.5-inch retro AR pistol styled after the Colt 9mm SMG of the 1980s, the boxy, slick-sided carbine famously carried by federal agencies and police units. Harrington & Richardson, the historic brand now revived by Palmetto State Armory, builds it as a semi-automatic, blowback-operated pistol that runs on Colt-pattern stick magazines.
Harrington Richardson 635 9mm Pistol Overview
56 rifle with an adapter. The upper is a slickside 9mm receiver with no forward assist, just like the original SMG, and the lower is a dedicated 9mm unit that accepts Colt-style magazines directly. Operation is straight blowback through a heavy 9mm carrier, so there is no gas tube to clean. 5-inch barrel is 4150 chrome moly vanadium steel in a lightweight profile with a nitride finish, a 1:10 twist and 1/2×28 threads wearing a 9mm A1 birdcage.
Furniture is the round six-hole carbine handguard, an A2-style grip and the H&R HAR-15 adjustable blade on the buffer tube.
Colt-Pattern Magazines
This pistol feeds from Colt SMG-style magazines, not Glock magazines. H&R notes compatibility with all Colt-style magazines and recommends ASC and Metalform for reliability. Spare magazines are widely available and reasonably priced, but quality varies, so buy from known makers and test each one. Distributor listings differ on the factory magazine, with some showing a 32-round magazine and the maker listing a 20-round one, so confirm what is in the box if capacity matters to you or to your state law.
How Blowback Feels
Blowback 9mm carbines and pistols are simple and reliable, but they recoil differently from a gas-operated AR. The heavy bolt slams forward and back, producing a sharper, more mechanical push than the 9mm cartridge alone would suggest. It is still very manageable and far softer than a short 5.56 pistol, with much less muzzle blast. Standard pressure 115 and 124 grain ammunition is the best starting point. Some owners add a heavier buffer to tame bolt speed, which is a reasonable tune for high round counts.
The HAR-15 Blade
The HAR-15 is an adjustable pistol stabilizing blade shaped to echo the sliding CAR-15 stock. Brace rules have shifted in recent years, and the 2023 ATF brace rule was vacated by a federal court in 2024, but the subject remains active. Do not fit a true stock to this 10.5-inch barrel unless you hold an approved ATF Form 1 or Form 4, because that creates a short-barreled rifle under the NFA. Threaded muzzles also make this a natural suppressor host, and suppressors require their own approved Form 4 and state legality.
Sights and Optics
The fixed carry handle with A1-style rear sight is part of the look, and with 9mm trajectories the irons are perfectly practical out to 50 or 75 yards. A carry-handle mount can hold a small red dot, though it sits high over the bore. Most buyers keep it as built and enjoy the old-school sight picture.
Practical Use and Care
With cheap 9mm ammunition, mild report and fast handling, this is a fun range pistol and a capable close-range defensive gun where legal. Blowback actions throw more carbon into the receiver than gas guns, so clean the bolt face and trigger area regularly. The barrel is not chrome lined but the nitride treatment resists wear and corrosion well.
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 many states cap magazine capacity at 10 or 15 rounds. Local rules on braced pistols and threaded barrels 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: Retro 635 pistol, SKU HR51655158977
- UPC: 810141220928
- Caliber: 9mm Luger
- Action: semi-automatic blowback
- Barrel: 10.5 inch lightweight 4150 CMV, nitride
- Twist: 1:10
- Muzzle: 9mm A1 birdcage, 1/2×28 thread
- Upper: slickside 9mm with carry handle
- Lower: dedicated 9mm, Colt SMG-pattern magazines
- Handguard: carbine six-hole
- Brace: H&R HAR-15 adjustable blade
- Grip: A2 style
- Trigger: mil-spec
- Finish: black anodized
- Magazine: one included (20 or 32 rounds depending on source)
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 buy quality Colt-pattern magazines rather than Glock-pattern ones.
Who It Is For
The Harrington Richardson 635 9mm Pistol is a great fit for retro AR collectors and range shooters who want the look of the classic Colt SMG with cheap 9mm ammunition and mild report.
Buy the Harrington Richardson 635 9mm Pistol at MAG5 Firearms
MAG5 Firearms is a family-owned FFL in Collegeville, Pennsylvania. Order the Harrington Richardson 635 9mm Pistol 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.
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