Bushmaster M-17s rifle (USA)

Bushmaster M-17s rifle, left side view

Bushmaster M-17s rifle, right side view, with installed Red Dot sight

Caliber: 5.56x45 mm (.223 Remington)
Action: Gas operated, rotating bolt
Overall length: 760 mm
Barrel length: 546 mm
Weight: 3.72 kg empty
Magazine capacity: Accepts all M16/AR15 magazines, standard capacity 30 rounds

This interesting weapon started its life in around 1982, when a small Australian company Armstech decided to develop a new assault rifle for Australian army trials. Prototype weapons were produced in a very short amount of time, but Australian army eventually selected for adoption an already established foreign weapon, the Austrian-made Steyr AUG. Nevertheless, Armstech kept developing and produced a series of interesting weapons, all in bullpup layout (and some firing caseless ammunition of indigenous design), but neither went past prototype stage. In around 1990 Armstech went belly up, and rights to the rifle that fired conventional ammunition was sold to another Australian company, known as Edenpine. Further development at Edenpine resulted in SAK 30 prototype, but company found that there's no market for such weapon in peaceful Australia. Therefore, in early 1990s Edenpine found an American company, Bushmaster Firearms Inc, which finalized the prototype and put it into production in 1994, just before the infamous "Assault weapons ban". Bushmaster designated new rifle as M17s and produced it in somewhat limited numbers up until 2005, when it was dropped from Bushmaster products line. It must be noted that demise of Bushmaster M17s was caused mostly by general preferences of American gun market, which is rather shy on bullpups; therefore, Bushmaster company decided to concentrate on much better selling rifles, patterned after Ar-15 / M16 or M4.
The M17s is a self-loading rifle, and thus cannot be classified as a true "assault rifle". Nevertheless it could make a very good paramilitary of home defense weapon; it is also good plinker and all-around compact rifle in .223 caliber, combining rifle-length barrel with carbine-style short overall length.

The M17s rifle is gas operated weapon that uses short-stroke gas piston, located above the barrel. Locking is achieved by rotary bolt with seven lugs; bolt is hosted in massive Ar-18-style bolt carrier, which rides on dual guide rods. The charging handle is somewhat unusual as it forms the rear part of the integral carrying handle, and therefore it is fully ambidextrous. The cocking handle slot on the top of receiver is covered by sliding dust cover. The receiver of weapon is a composite affair, consisting of extruded aluminum upper part and polymer lower part. Upper part houses barrel, gas system and bolt group. Lower receiver is made integral with pistol grip and houses trigger unit and magazine housing. Upper and lower receivers are connected by two push-out cross-pins. Ejection port is made on the right side of the weapon only, and there's no provisions for left-hand ejection. Nevertheless, weapon is more or less ambidextrous in regard to controls, as push-button safety (located at the front of triggerguard) and magazine release buttons are made ambidextrous too. M17s will accept all M16 / Ar-15 type magazines. The top of the carrying handle is fitted with Weaver-style accessory rail which will accept any compatible scope mounts, and also hosts a rudimentary backup open sight.