The Heckler & Koch MR556 A4 in 5.56 NATO is a semi-automatic short barreled rifle featuring an 11" threaded barrel and 30-round capacity, built for uncompromising performance and durability. Designed around HKs proven short stroke gas piston system, this HK MR556 A4 5.56 NATO SBR delivers exceptional reliability with reduced fouling and wear. Engineered for hard use, it combines refined ergonomics, ambidextrous controls, and suppressor-ready adaptability in a compact platform.