H&R Model 606

What Was the Original Model 606?

The original Harrington & Richardson Model 606 was produced in the early 1960s as ArmaLite licensed the AR-15 design to multiple manufacturers in an attempt to generate military interest. H&R produced a heavy-barrel variant intended as a squad automatic weapon candidate — the first HBAR AR-15 ever built. Military procurement went elsewhere, and the Model 606 was produced in very limited numbers before the program ended. The rifles that survived became collector pieces, with very few examples known to exist. For sixty years the Model 606 was a mythological object in AR-15 collecting circles, known mostly from photographs and the accounts of the few who had handled one.

H&R Model 606 Specifications

Caliber: 5.56 NATO. Barrel: 20” heavy profile (HBAR), 4150 Chrome Moly Vanadium, chrome-lined, 1:7 twist, 1/2×28 threaded, Parkerized finish. Weight: approximately 9 lbs with bipod. Receiver: forged 7075-T6, gray Type 3 hard coat anodized, slick-side M16-style (no forward assist, no dust cover). Handguard: M16A1 triangular with heat shields. Stock: fixed A1-style. Grip: A1-style. Bipod: M2-style (M14 pattern) pinned at muzzle, included. Sights: A1-style rear aperture and front post.

What Is a “Slick Side” Receiver?

A slick-side receiver is the original AR-15/M16 configuration — no forward assist and no dust cover on the right side of the upper receiver. Early AR-15s and the original M16 did not have a forward assist; the Army added it in the M16A1 after concerns about reliability in Vietnam, despite ArmaLite engineer Eugene Stoner arguing it was unnecessary. The slick-side configuration is correct to the original Model 606 and to early commercial AR-15s of the period. Beyond historical authenticity, the slick-side upper is slightly lighter and cleaner in appearance than the standard forward-assist configuration.

Model 606 vs Standard AR-15: The HBAR Advantage

The Model 606’s heavy-barrel profile is the defining feature that makes it historically significant and practically distinct from standard AR-15s. A heavy barrel has more material around the bore, which absorbs heat more slowly during sustained fire, maintains accuracy longer in rapid-fire strings, and produces a stiffer, more harmonically consistent barrel that benefits precision shooting. The 20-inch length maximizes muzzle velocity with 5.56 NATO ammunition. For buyers who want a historically significant AR-15 that is also a legitimate precision and sustained-fire platform, the Model 606 delivers both in a package that no other production rifle currently replicates.

H&R Heritage: Why PSA Relaunched the Brand

Harrington & Richardson is one of the oldest American firearms manufacturers, founded in 1871 in Worcester, Massachusetts. PSA acquired the H&R brand and has used it to relaunch historically significant American firearms that have been out of production for decades. The Model 606 is the most ambitious H&R relaunch to date — not just a new variant but a faithful recreation of a rifle so rare that most AR-15 collectors have never seen one in person. For collectors and enthusiasts who appreciate American firearms history, the Model 606 represents a genuine opportunity to own a piece of AR-15 heritage that was previously inaccessible.

Related Pages

See the full H&R lineup from PSA, or browse all AR-15 rifles. Explore collector firearms for other historically significant platforms, and visit 5.56 ammunition for load recommendations suited to the Model 606’s 20-inch 1:7 twist barrel.