 Improvements, such as the addition of a carrier/lafette backpack and a longer barrel, led to the M1A1 variant, but at 21 kilograms its combat weight was deemed excessive.The M1 was essentially a sniper weapon, not primarily intended for military field application, but for anti-terrorist police and special forces' use, who operate on the "one shot, one kill" principle.The single shot action was designed to reduce the number of moving parts and allow for extreme precision, five hits out of five shots fit in a 25 centimeter radius circle at 1300 meters.