Brownells 75th Anniversary - A Shooting Heritage

Replica of the Original AR-15 Prototype

From 308 to 5.56

Step into the Wayback Machine and go back to the beginning of the AR-15 with our BRN-PROTO® - a faithful replica of the Eugene Stoner's very first AR-15 prototype. If you're an AR-15 aficionado or collector, the BRN-PROTO® is a rifle you should not be without! Based on AR-15 Serial Number One, the Brownells' BRN-PROTO® sports a wealth of unique, historically-accurate features you will not see on later AR-15 / M16 models.

First, the BRN-PROTO® has the distinctive trigger-like charging handle on top of the receiver, under the carry handle, just like the early AR-10 models (remember, the AR-15 was developed second.). It has the uncluttered “slick-side” upper receiver of the early rifles and stock, handguard, and pistol grip of brown reinforced polymer that replicates the look - but not the weaknesses - of the original fiberglass furniture. If the round cross-section handguard looks oversized, that's because it is. Just as the original was a "borrowed" AR-10 'guard, it's actually lifted from our BRN-10 .308 rifles!

Model: BRN-PROTO® Overview

The BRN-PROTO AR-15 gives you the looks and functionality of the original without the drawbacks. It is constructed of the latest materials using the latest manufacturing techniques, so you have an robust rifle that's ready to put a LOT of rounds down range. Internal dimensions conform to modern "mil-spec" standards, so the BRN-PROTO® is compatible with off-the-shelf upgrade and replacement parts.

  • Chambered for modern 5.56x45mm NATO (.223 Remington compatible) ammunition
  • Robust forged/machined 7075 T6 aluminum receivers
  • Matte gray anodizing
  • 20" barrel with 1-12" rifling
  • Rifle-length gas tube
  • Chrome-plated bolt / carrier group
  • Includes:
    • One (1) 25rd Magazine
    • One (1) GI Operations Manual
    • One (1) Chamber Flag

Own the BRN-PROTO® rifle from Brownells.

Rifle Details:

Action Type:

Direct Impingement

Barrel Length:


Twist Rate:



5.56 mm NATO


Anodized Matte Gray

Front Sight:




Magazine Included:

25rd Magazine


Duckbill Flash Hider

Rear Sight:


Stock Material:



6lbs 11oz

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Model: BRN-PROTO® Details

Lower Receiver: The BRN-PROTO® uses the BRN-601 slabside lower receiver with matte gray anodizing.

Upper Receiver: The matte gray anodized upper is slickside, without a forward assist or shell deflector.

Note: The lower features a faux buffer tube retaining roll pin

Charging Handle: The BRN-PROTO® has the distinctive trigger-style charging handle in the top of the receiver, under the carry handle, just like the first AR-15 prototypes.

Front Sight Base & Handguards: The front sight base mirrors that found on AR-15 Serial No. 1. The handguards are the same as used on the BRN-10A, just like the first AR-15 borrowed handguards from the earlier AR-10.

Flash Hider: Original style duckbill 3-prong flash hider installed with split washer, just like the first rifles.

Sights: M16A1 rear and front sights.

Bolt Carrier Group: Chrome M16 bolt carrier assembly. 9310 tool steel bolt is particle inspected and test fired with 10 rounds. 8620 steel carrier, with gas key screws properly torqued & staked.

Magazine: Comes with original-style 25-round magazine, exclusive to Brownells.

Pistol Grip: Brownells M16A1 brown pistol grip.

Manual: A reprint of "The M16A1 Rifle: Operation & Preventative Maintenance," the famous comic-book-style Army manual by cartoonist and graphic artist Will Eisner. First issued in 1969.

Model: BRN-PROTO® Aditional Images

BRN-Proto Forward Right BRN-Proto Backward Left BRN-Proto Ejection Side BRN-Proto Back Side BRN-Proto Flash Hider BRN-Proto Buttstock Type D BRN-Proto Buttstock And Grip BRN-Proto Ejection Side Detail BRN-Proto Pistol Grip Detail BRN-Proto Upper Reciever No Forward Assist BRN-Proto Trigger-Style Charging Handle Detail BRN-Proto Dust Port Cover Detail BRN-Proto Non-Retained Pin Detail BRN-Proto Handguard Detail BRN-Proto Handguard BRN-Proto Handguard And Front Sight Detail BRN-Proto Front Sight Detail

Click Image Above To Open Expanded View

BRN-Proto Forward Right Thumbnail
BRN-Proto Backward Left Thumbnail
BRN-Proto Ejection Side Thumbnail
BRN-Proto Back Side Thumbnail
BRN-Proto Flash Hider Thumbnail
BRN-Proto Buttstock Type D Thumbnail
BRN-Proto Buttstock And Grip Thumbnail
BRN-Proto Ejection Side Detail Thumbnail
BRN-Proto Pistol Grip Detail Thumbnail
BRN-Proto Upper Reciever No Forward Assist Thumbnail
BRN-Proto Trigger-Style Charging Handle Detail Thumbnail
BRN-Proto Dust Port Cover Detail Thumbnail
BRN-Proto Non-Retained Pin Detail Thumbnail
BRN-Proto Handguard Detail Thumbnail
BRN-Proto Handguard Thumbnail
BRN-Proto Handguard And Front Sight Detail Thumbnail
BRN-Proto Front Sight Detail Thumbnail
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