|In service 2010–Present|
Manufacturer Swiss Arms AG
|Type Assault rifle
Place of origin Switzerland United States
Designer Robert Hirt Christopher Sirois
The SIG Sauer SIG516 is a firearm manufactured by SIG Sauer. The rifle is based on the earlier 5.56×45mm NATO AR-15 and the M16.
The SIG516 is a semi-automatic firearm multi caliber rifle, intended for civilian and law enforcement markets. The same family also includes selective-fired "assault rifles", strictly intended for law enforcement and military use. It fires from a closed bolt, and has a short-stroke push rod piston system. The gas piston pushes the bolt carrier rearward, where it is returned to the forward and locked position by a spring. This process loads the next cartridge. The 516 has a four position gas regulator, allowing the user to choose the amount of gas directed to the piston. This is used with suppressors and 40mm applications.
The SIG516 has a safety lever on the left side, to be used by the thumb of the shooting hand. The gas block integrates an adjustable gas regulator. The front gas block is railed to accept the front sight with a flip-up sight post. SIG516 models are equipped with an M16A2 style bird-cage flash hider.
All SIG516 models except the Marksman are equipped with 16 inch barrels shrouded by a free-floating M1913 Picatinny rail, as well as flip up iron sights (BUIS) made by SIG Sauer.
The 5.56×45mm NATO SIG516 models accept AR-15 style box magazines. These magazines are constructed in 5-, 10-, 20-, and 30-round variants. SIG516 Russian rifles must use a different magazine, as they are chambered in 7.62×39mm. The SIG516 Russian uses magazines designed for 7.62×39mm AR-15 rifles. The rifle is hammer-fired and has a two-stage trigger mechanism in the SIG516 Marksman, while all others have a military specification single stage trigger.
A bolt hold-open device locks the bolt carrier assembly open after expending the last cartridge from the magazine and is released by pushing the bolt catch lever located on the left side of the receiver. Alternatively, a left-handed shooter may release the bolt by pulling the charging handle a short distance to the rear.