Like the AUG, the ACR is a bullpup design with the 24-round magazine located quite close to the buttstock of the gun.

The chamber was normally held in the "down" position, the trigger releasing it to allow the springs to drive it upward and fire.

The Steyr ACR's rounds consist of a saboted carbon steel flechette packaged in a telescoped arrangement with propellant packed around the projectile.

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.