Harrington & Richardson Retro DOE Features The H&R Retro DOE 9mm Pistol is styled after the original Dept. of Energy SMG and while it s compatible with all Colt style magazines ASC and Metalform magazines are recommended for best function. A 4150 chrome moly vanadium barrel with a 1:10 twist rate and nitride finish delivers durability and consistent accuracy while the slickside 9mm upper receiver maintains the clean authentic profile of the original design. The DOE/M231 handguard includes heat shields protecting the shooter s support hand during extended strings of fire. For collectors who want an authentic retro profile without sacrificing modern reliability the Harrington & Richardson Retro DOE s slickside upper and period-correct handguard deliver that genuine look. This pistol features the H&R HAR-15 adjustable pistol brace that keeps the retro build compliant while maintaining the classic aesthetic the DOE platform is known for. An A2 style pistol grip and carry handle iron sights round out the retro-correct ergonomics while a manual safety and mil-spec trigger keep operation straightforward and familiar. A thread protector ships with the pistol covering the 5/8x24 threaded muzzle until the shooter adds a suppressor or other muzzle device. For shooters who want a period-correct AR pistol platform with genuine retro details the Retro DOE delivers that authenticity in a modern compliant package. Harrington & Richardson Retro DOE Specifications Manufacturer: Harrington & Richardson Model: Retro DOE Type: AR Pistol Caliber: 9mm NATO Capacity: 20 Rounds Color: Black Action: Semi-Automatic Striker Fired Barrel Length: 7.5 in Barrel Material: 4150 Chrome Moly Vanadium Barrel Finish: Nitride Barrel Profile: Lightweight Twist Rate: 1:10 Threaded Barrel: Yes Thread Pattern: 5/8x24 Muzzle: Thread Protector Receiver Description: Slickside 9mm Upper Handguard: DOE/M231 with Heat Shields Grip: A2 Style Stock Description: H&R HAR-15 Adjustable Pistol Brace Sights: Carry Handle Iron Sights Trigger: Mil-Spec Safety: Manual Finish: Black Anodized Included Magazines: 1 Magazine Available At: GrabAGun