The AR-70/90 is a gas operated, magazine fed, selective fire weapon. The receiver is made from stamped sheet steel, and consist of two halves, upper and lover, connected by two cross-pins, at the rear and at the front. For maintenance and field stripping the rear pin is pushed out and the receiver is hinged around the front pin. If required, the front pin can be removed too, so the receiver halves will be separated completely. On the AR-70/223 the upper receiver is of square cross-section, with stamped bolt guides. This design proved to be not strong enough, so the AR-70/90 features a trapezoid-shaped upper receiver cross-section, with separate bolt guides welded in place.
The gas operated action of the AR-70/90 is fairy conventional, with the longstroke gas piston, located above the barrel. The gas piston rod is linked to the bolt carrier by using a cocking handle as a lock, and the return spring is located around the gas piston, above the barrel. The gas block featured a two positions gas regulator (for normal and adverse conditions), and the gas cutoff,integral with raising grenade sight. When grenade sight is raised into the firing position, it automatically closes the gas port. The rotating bolt is somewhat similar to one, found in the Kalashnikov AK-47 rifles, and has two massive lugs, which are locked into the barrel sleeve, which is welded into the receiver. The charging handle is attached to the bolt carrier.
The barrel is fixed to the receiver using the threaded barrel nut, allowing for quick barrel replacement (for repair purposes only, not in the field), without the extensive headspace adjustments. The barrel bore is chrome-plated.
The conventional trigger / hammer mechanism allows for single shots and fullauto on the AR-70/223 rifles and for single shots, 3 rounds bursts (optional)and full auto on AR-70/90 series rifles. The safety /selector switch is ambidextrous on AR-70/90 series rifles, and is located on the right side of the receiver on the AR-70/223 series rifles.
The feeding of AR-70/90 series weapons is achieved by using STANAG (M16-type)compliant magazines, with the ambidextrous magazine release button located at the both sides of the magazine housing in the lower receiver. On the AR-70/223 rifles, feeding was from the proprietary 30 rounds magazines, with the magazine release lever located between the magazine and the trigger guard. Both AR-70/90 and AR-70/223 series rifles featured a bolt stop device, which holds the bolt open when the last round from the magazine is fired. The bolt release button is located at the left side of the receiver, above the magazine housing.
The sights of the AR-70/90 rifles consists of the hooded front blade, mounted on the top of the gas block, and the flip-up aperture rear, marked for 250 and400 meters range. The top surface of the receiver is fitted with the NATO-standard scope / accessory rail. A detachable carrying handle with thesee-through base is available for all AR-70/90 series rifles. The AR-70/90 also can be equipped with Zeiss "Orion" night-vision sight or the Aimpoint4X telescope sight (any other sights with compatible mountings also can be easily installed, if required).
The furniture on all rifles is made from plastic, with the standard rifle shaving the fixed plastic buttstocks. The SC-70/223 and SC-70/90 Special Forces carbines are different from AR rifles only by having the side-folding, skeleton type metallic buttstocks, covered with plastic. The SCP-70/90 carbine is similar to the SC-70/90 except that it has a shortened barrel which cannot be used to launch rifle grenades directly. However, a special detachable rifle grenade launcher is available for short barreled carbines, which could be easily clamped onto the muzzle of the gun. The hollow pistol grips of all AR-70/90 series rifles is used to store a cleaning kit.
A wide variety of accessories is available for AR-70/90 rifles, including knife-type bayonets, lightweight, foldable and detachable bipods, blank firing adaptors etc[1].
