First Look: Brownells BRN-601 Upper Receiver

Perfect for your retro-themed AR-15.

posted on November 7, 2023
Brownells 601 upper

Brownells is re-introducing the historical and retro styled BRN-601 upper receiver for AR-15 pattern rifles.

The BRN-601 is a detailed and accurate replica of the vintage upper receiver found on the first AR-15 pattern rifle adopted during the early 1960s. It has a period-correct, gray-anodized “slickside” fixed carry handle upper receiver with a 20-inch-long pencil barrel that has the original, slower 1:12-inch twist rate. The muzzle is topped with the vintage “duckbill” three-prong flash hider. Brownells has also included a vintage styled “slickside” chrome M-16 profile bolt carrier group (BCG) that is machined from 9310 alloy steel. This upper receiver also sports a set of olive drab polymer traditional “triangular” AR-15 handguards found on M-16s during the 1960s and '70s prior to the M16-A2 upgrades. The green color mimics the original vintage upper receivers that had their handguards painted by hand.

The 1:12-inch-twist-rate barrel was originally intended to stabilize 55-grain projectiles, and ammunition with this bullet weight is ideal for the BRN-601. Unlike the original bolt carrier group, the BRN-601’s carrier group comes with modern firing pin, modern gas key screws and a properly staked gas key for added safety and reliability.

Brownells BRN 601 Specifications:

  • Upper Receiver: Slickside fixed carry handle
  • Barrel Length: 20 inches
  • Barrel Twist: 1:12-inches
  • Chamber: 5.56 NATO
  • Sights: 5 position front sight, original rear sight adjustable for windage only
  • Finish: Matte gray anodizing (original style)
  • Flash Hider: Three-prong duckbill

Vintage Colt 601 upper receivers are extremely collectable and no longer easily found, so the BRN-601 is ideal for AR-15 fans who want an affordable and accurate replica of the original for their “retro” AR build. This modern produced complete upper receiver has a starting retail price of $899. To learn more, visit


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