SIG Sauer SIG516

The SIG Sauer SIG516 is a semi-automatic rifle manufactured by SIG Sauer. It is an AR-15 style rifle chambered in 5.56×45mm NATO. Introduced in 2010, the SIG516 was discontinued as of 2019. A variant chambered in 7.62x51mm NATO, the SIG716, remains in production.
Design details.
Operating mechanism.
The SIG516 is a semi-automatic multi-caliber rifle. 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.
Features.
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 use a different magazine, as they are chambered in 7.62×39mm. The SIG516 Russian uses magazines designed for 7.62×39mm AR-15 style 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.
It is built to pass the NATO test protocol “Over the Beach”, meaning the SIG516 is designed to fire safely as quickly as possible after being submerged in water.
Variants.
SIG716.
The SIG716 is battle rifle/designated marksman rifle (DMR) variant, which is based on the same design, but is chambered for the larger 7.62x51mm NATO round and uses SR-25 pattern magazines.
SIG716 G2.
The SIG716 G2 (Generation 2) variant features a short-stroke pushrod gas system. This operating system reduces carbon fouling, excessive heat and unburned powder in the action, ensuring further improved reliability and function. The G2 Patrol model is chambered in 7.62×51mm NATO, while the G2 DMR model is chambered in 6.5mm Creedmoor.
SIG716 i.
The SIG716 i (impingement) variant features a direct impingement gas system instead of short-stroke pushrod gas system. This operating system has helped Sig Sauer to bring down the cost of manufacturing and pushing more sales of SIG716 i, while improving the accuracy and improving weight reduction. The SIG716 i model is chambered in 7.62×51mm NATO. Sig Sauer appears to have discontinued SIG716 and SIG716 G2 models, since the company stopped displaying these products in their website, while they continue to sell magazines and spare parts in their online store. The SIG716 i has been recognized as the best AR-10 rifle for the year 2020, by readers' choice voting of Ballistic magazine.