1969, Rock Island Arsenal M21 Sniper weapons system. The M21 was developed from the standard M14 rifle itself a further development of the highly successful world war 2 -ara M1 Garand. With a 5,10,20 round magazine.
1970, Ingram mac-10 (M10). Compact sub machine gun initiative seeing limited production and equally-limited action across the globe. With a 30 round magazine.
1982, Barrett M82 designated as the "M107" in us military service, was introduced in 1986 by the American Barrett Firearms company and was develop as a scoped, long-range, heavy-Caliber anti-material rifle. And with a 10 round magazine.
The most important gun is the Barrett M82 because it has a long range that mean it will kill someone from far away and a 10 round magazine.