Steyr ACR
Encyclopedia
The Steyr ACR was a prototype flechette
-firing assault rifle
built for the US Army's Advanced Combat Rifle
program of 1989/90. Although the Steyr
design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better than the M16A2, the baseline for a successful ACR weapon.
, although it is rounder and the barrel is covered for almost its entire length, as opposed to the AUG where much of the barrel was exposed. Like the AUG the ACR is a bullpup
design with the 24-round magazine located quite close to the buttstock of the gun. The stock was "split" from the magazine forward to a location just below the sights to open for cleaning. An optical sight was included as a standard feature.
The Steyr employed a unique system to cycle through ammunition: instead of driving rounds forward into the chamber and being held in place by a locking bolt, the entire chamber traveled vertically the width of the round. After firing the gases "blew" the chamber vertically downward where a new round was forced into the chamber from the rear, forcing the old round out an ejection port ahead of the magazine. Springs then raised the chamber back into position where it was locked into a fixed block. The firing pin was fixed above the chamber, entering through a small hole and striking the ring of primer to fire. The chamber was normally held in the "down" position, the trigger releasing it to allow the springs to drive it upward and fire.
packaged in a telescoped arrangement with propellant packed around the projectile. The case of the ammunition was made of a light weight translucent plastic instead of conventional brass making the rounds weigh less than half the weight of standard 5.56x45mm NATO ammunition.
Flechette
A flechette is a pointed steel projectile, with a vaned tail for stable flight. The name comes from French , "little arrow" or "dart", and sometimes retains the acute accent in English: fléchette.-Bulk and artillery use:...
-firing assault rifle
Assault rifle
An assault rifle is a selective fire rifle that uses an intermediate cartridge and a detachable magazine. Assault rifles are the standard infantry weapons in most modern armies...
built for the US Army's Advanced Combat Rifle
Advanced Combat Rifle
The Advanced Combat Rifle was a United States Army program to find a replacement for the M16 assault rifle. The program's total cost is approximately US$300 million...
program of 1989/90. Although the Steyr
Steyr Mannlicher
Steyr Mannlicher is a firearms manufacturer based in the city of Steyr, Austria. Originally a part of the Steyr-Daimler-Puch manufacturing conglomerate, it became independent when the conglomerate was broken in 1990.-History:...
design proved effective, as did most of the weapons submitted, the entire ACR program ended with none of the entrants achieving performance 100% better than the M16A2, the baseline for a successful ACR weapon.
Design
The Steyr ACR has some superficial resemblance to the Steyr AUGSteyr AUG
The AUG is an Austrian bullpup 5.56mm assault rifle, designed in the early 1970s by Steyr Mannlicher GmbH & Co KG . The AUG was adopted by the Austrian Army as the StG 77 in 1977, where it replaced the 7.62mm StG 58 automatic rifle...
, although it is rounder and the barrel is covered for almost its entire length, as opposed to the AUG where much of the barrel was exposed. Like the AUG the ACR is a bullpup
Bullpup
Bullpups are firearm configurations in which the action is located behind the trigger group and alongside the shooter's face, so there is no wasted space for the buttstock as in conventional designs. This permits a shorter firearm length for the same barrel length for improved maneuverability, and...
design with the 24-round magazine located quite close to the buttstock of the gun. The stock was "split" from the magazine forward to a location just below the sights to open for cleaning. An optical sight was included as a standard feature.
The Steyr employed a unique system to cycle through ammunition: instead of driving rounds forward into the chamber and being held in place by a locking bolt, the entire chamber traveled vertically the width of the round. After firing the gases "blew" the chamber vertically downward where a new round was forced into the chamber from the rear, forcing the old round out an ejection port ahead of the magazine. Springs then raised the chamber back into position where it was locked into a fixed block. The firing pin was fixed above the chamber, entering through a small hole and striking the ring of primer to fire. The chamber was normally held in the "down" position, the trigger releasing it to allow the springs to drive it upward and fire.
Ammunition
The Steyr ACR's rounds consist of a carbon steel flechette for a projectile that used a four part spindle sabotSabot
A sabot is a device used in a firearm or cannon to fire a projectile, such as a bullet, that is smaller than the bore diameter, or which must be held in a precise position. The term is also applied to a battery stub case, a device used similarly to make a small electrical battery usable in a...
packaged in a telescoped arrangement with propellant packed around the projectile. The case of the ammunition was made of a light weight translucent plastic instead of conventional brass making the rounds weigh less than half the weight of standard 5.56x45mm NATO ammunition.
Performance
During testing the weapon performed well, and only two problems were identified. One was that the plastic cases had varying strengths, which has some effect on the ballistics. This was considered to be a fairly minor problem, one they expected could be solved through better materials and quality control. The other issue was somewhat more difficult to solve; when the sabots left the barrel they were still going quite fast, and presented a danger to other soldiers as well as to the shooter if they bounced off the ground when firing prone.Rifle
See also
- Colt ACRColt ACRThe Colt ACR was Colt's entry in the U.S. DoD Advanced Combat Rifle program, which concluded with the result that none of the entrants achieved enough of an improvement over the M16 to be worth the cost....
- HK ACRHeckler & Koch G11The Heckler & Koch G11 is a non-production prototype assault rifle developed during the late 1960s, 1970s and 1980s by Gesellschaft für Hülsenlose Gewehrsysteme , a conglomeration of companies headed by firearm manufacturer Heckler & Koch , Dynamit Nobel The Heckler & Koch G11 is a non-production...
- Special Purpose Individual WeaponSpecial Purpose Individual WeaponThe Special Purpose Individual Weapon was a long-running United States Army program to develop, in part, a workable flechette-based "rifle", though other concepts were also involved...
- Steyr AMR 5075/Steyr IWS 2000Steyr IWS 2000The Steyr IWS 2000 is an Austrian semi-automatic anti-materiel rifle, produced by Steyr Mannlicher. IWS stands for Infantry Weapon System. It is actually a smoothbore weapon, like many modern tank guns, and not a true rifle but this can help accelerate projectiles and increase ballistic effectiveness...
prototype long range sniper rifle fires similar but larger rounds - Polymer-cased ammunitionPolymer-cased ammunition-Overview:A plastic cylinder makes up the body of the cartridge. Starting from the back of the interior of the cartridge: The primer material. A priming method for rimfire cartridges is disclosed in which a propellant solution is disposed adjacent a centrifugally located primer material in a...