The M40 series is a highly modified Remington 700 hunting rifle, chambered in .308 Winchester/7.62x51mm NATO. The A5 model comes equipped with a custom, 1–12 twist twenty-five-inch Schneider barrel.

The M40A5 is the latest in a long line of M40 sniper rifles used by the U.S. Marine Corps. The M40 series is a highly modified Remington 700 hunting rifle, chambered in .308 Winchester/7.62x51mm NATO.

The M40 rifle was the same type of weapon used by Marine sniper Sgt. Charles "Chuck" Mawhinney. Mawhinney is the deadliest sniper in Marine Corps history, with 103 confirmed kills.