Steyr ACR
Steyr Mannlicher · Assault Rifle · Prototype · 1989
Also known as: Steyr Advanced Combat Rifle, Steyr ACR Flechette Rifle
Overview
The Steyr ACR is an Austrian prototype bullpup assault rifle developed by Steyr Mannlicher in 1989 as a contender in the U.S. Army's Advanced Combat Rifle (ACR) program. It fired a unique 1.5mm fin-stabilised flechette dart packed inside a synthetic, plastic-cased telescoped cartridge, launched at roughly 1,450 m/s for an exceptionally flat trajectory. A rising-chamber breech driven by an annular gas piston around the barrel handled feeding and ejection. The program sought a 100 percent improvement in hit probability over the M16A2; when no candidate reached that goal, the ACR effort was terminated and the rifle never entered production.
Specifications
| Weight (empty) | 3230 g (113.9 oz) |
| Overall Length | 780 mm (30.71") |
| Barrel Length | 541 mm (21.30") |
| Action Type | Gas Operated |
| Firing Mechanism | Striker Fired |
| Trigger Type | Single Action |
| Magazine Capacity | 24 rounds |
| Magazine Type | Detachable Box |
| Muzzle Velocity | 1450 m/s (4757 fps) |
| Muzzle Energy | 694 J (512 ft·lbf) |
| Effective Range | 600 m (656 yd) |
| Rate of Fire | 1200 rpm |
| Barrel Rifling | Smoothbore |
| Frame Material | Polymer |
| Barrel Material | Steel |
| Stock Material | Polymer |
| Finish | Matte Black |
Calibers
- 1.5mm Steyr Flechette · primary — also known as Steyr ACR flechette, Steyr SCF (Synthetic Cased Flechette)
Features
- Firing modes: Semi Automatic, Burst 3
- Feed systems: Detachable Box Magazine
- Safety mechanisms: Manual Safety
- Features: Bullpup Layout, Rising Chamber Breech, Annular Gas Piston, Synthetic Cased Telescoped Ammunition, Flechette Projectile, Translucent Magazine, Integral Optical Sight
Service history
Operators
- United States Army (trials only) · adopted 1989 · as ACR candidate
Production
Production years: 1989-1990
Only a small number of prototype/trials examples were built for the U.S. Army ACR program; never mass-produced.
Origin
Country of origin: Austria
Designer: Steyr Mannlicher
Discontinued: 1990
Notes
The cartridge is variously described as a Synthetic Cased Flechette (SCF) round; the flechette is about 1.5 mm in diameter, roughly 41 mm long and weighs about 0.66 g (10 grains). Because the projectile is a smoothbore-launched dart, the barrel is unrifled.
Background
The ACR program of the late 1980s pitted Steyr's flechette rifle against caseless (Heckler & Koch), duplex (Colt) and flechette (AAI) designs. None of the four candidates achieved the demanded 100 percent improvement in hit probability over the M16A2, and the U.S. Army shelved the entire effort, leaving the Steyr ACR a museum-bound curiosity.