|SIG 751 SB||SIG 751 LB|
|Caliber:||7.62×51 NATO / .308 Winchester|
|Action||Gas operated, long stroke piston, rotary bolt locking|
|Overall length||870 / 643 mm||960 / 733 mm|
|Barrel length||326 mm / 12.8"||416 mm / 16.4"|
|Weight, less magazine||3.63 kg||3.82 kg|
|Rate of fire (for MIL/LE versions only)||650 rounds per minute||650 rounds per minute|
|Magazine capacity||20 rounds|
The SIG SAPR (Semi-Automatic Precision Rifle) was first announced in 2004 by the Swiss-based branch of the international SIG-Sauer arms making company, and, apparently, entered initial production in Switzerland in 2009. Over the development years the SIG SAPR system evolved into two branches – one retained semi-automatic mode of fire and is intended for civilian and law enforcement markets; another is a select-fire battle / assault rifle, which is intended for Military and special Law Enforcement applications only. The SIG SG 751 SAPR rifles are based on the time-proven 5.56mm SIG SG 550 / Stgw.90 family of rifles, with major elements of the action necessarily enlarged and strengthened to handle bigger and more powerful 7.62 NATO / .308 Win ammunition. At the present time, SIG SG 751 SAPR rifles are offered in two military versions (SB – short-barreled and LB-Long Barreled). Civilian versions may have different barrel lengths (currently advertised civilian-legal versions have barrels 455 or 570 mm long) and, obviously, cannot fire in full automatic or burst modes.
The SIG SG 751 SAPR rifle is gas operated, with gas piston removably attached to the bolt carrier, and with rotating bolt with two massive lugs. The recoil spring is located around the gas piston rod, above the barrel, and the bolt carrier is attached to the gas piston rod by the mean of removable charging handle. The gas block is equipped with manual gas regulator with four positions (normal operations / adverse conditions / for use with silencer / shut-off, manual reload). The receiver of the SIG SG 751 SAPR rifle is assembled from two parts – stamped steel upper and aluminum alloy lower, connected by the captive push-pins. The controls are ambidextrous, and in MIL / LE versions the combined safety / selector lever has 4 positions – for Safe, Single shots, 3-round bursts and Full-automatic fire. In civilian-legal versions this lever has only 2 positions – for Safe and Fire. Feed is from proprietary 20-round detachable box magazines, made of plastic. Cold-hammer forged barrel can be easily replaced if needed. Barrel is free-floated for maximum accuracy. The sighting equipment is installed on the integral Picatinny rail on the top of the receiver, and normally SIG SG 751 SAPR rifle is provided with back-up iron sights, consisting of folding front sight and drum-type diopter rear sight. The polymer side-folding stock is same as used on the5.56mm SIG SG 550 / Stgw.90 rifles.