One Horse Express Rifle with Atrius FRS

Factory-built 16-inch AR-15 with a single-side Atrius Forced Reset Selector fitted, timed, and tested by One Horse.

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Key Highlights

•Factory-installed Atrius Single Side FRS with Safe, Semi, and Super Semi positions
•16-inch SOCOM-profile 5.56 barrel with mid-length gas
•15-inch M-LOK handguard and standard AR-15 accessory interfaces

Specifications

Price: $999
Weight: 7 lb 2.2 oz
Calibers: 5.56x45mm, .223 Rem
Rail Type: mlok
Best For: range training home defense

Capability Profile

0-10 Scale Across 8 Axes

Compatibility Tags

family: modern-riflefamily: ar-patterntrigger: ar-fcgcaliber: 556interface: picatinny-tophandguard: mlokbarrel: longthread: 1/2x28mag-type: stanagreceiver-pattern: ar-15

Overview

The One Horse Express is a 16-inch 5.56 AR-15 built around a factory-installed Atrius Single Side Forced Reset Selector. One Horse fits, times, and tests the selector as part of the complete rifle. Its three selector positions are Safe, Semi, and Super Semi.

The rifle uses a SOCOM-profile barrel with a 1:8 twist, mid-length gas, 1/2x28 muzzle threads, and an A2 muzzle device. A 15-inch Express M-LOK handguard leaves room for a light, sling mount, and support-hand accessories. The flat top accepts common Picatinny optics, and the rifle feeds from standard AR-15 magazines.

The Breek Arms Warhammer MOD2 charging handle, THRiL RTG grip, THRiL CCS stock, and 30-round magazine ship with the rifle. The factory FRS setup is the reason to choose this model over a standard value-tier AR: the selector arrives installed and timed instead of leaving that work to the buyer.

Key Features

Factory-installed Atrius Single Side Forced Reset Selector
Safe, Semi, and Super Semi selector positions
16-inch SOCOM-profile 5.56 NATO barrel with 1:8 twist
Mid-length direct-impingement gas system
15-inch Express M-LOK handguard with Picatinny top rail
Breek Arms Warhammer MOD2 ambidextrous charging handle
THRiL RTG grip and adjustable THRiL CCS stock
1/2x28 muzzle threads with A2 muzzle device

Pros

+Atrius FRS arrives fitted, timed, and tested in the complete rifle
+Mid-length gas and 16-inch barrel retain familiar AR-15 handling and ballistics
+M-LOK, Picatinny, STANAG, and 1/2x28 interfaces support common AR accessories
+Ambidextrous charging handle ships installed

Cons

−Single-side selector is less flexible than the optional ambidextrous Atrius version
−No sights or optic are listed with the base rifle
−Forced-reset legality and transfer eligibility vary by jurisdiction