SIG Sauer SIG 556 5.56x45mm 16” Semi-Auto Rifle Folding Stock & Mag
SOLD FOR: $1,700.00
LSB#: LSB260529ZM008
Make: Sig Sauer Inc.
Model: SIG 556
Serial Number: JS 033287
Year of Manufacture: Modern
Caliber: 5.56x45mm / .223 Rem.
Action Type: Semi-Automatic, Short Stroke Gas System, fed by detachable AR15 pattern magazines.
Barrel Length: 16”. 17.5” with A2 flash hider
Sights / Optics: The front sight is a green fiber blade set into a hooded base set to the gas block. The rear sight is a 4-position diopter with two green fiber inserts set into the receiver mounted picatinny rail.
Stock Configuration & Condition: This rifle has a three-piece ribbed polymer set with a clamshell forend, pistol grip w/ storage gate, and a folding adjustable stock with a rubber buttpad. There are light scratches and scuffs throughout. There are no chips or cracks. The LOP is 13.25” from the front of the trigger to the back of the buttpad. Overall this polymer furniture set is in Very Good condition.
Magazine Quantity & Condition: 1x 30rd steel magazine in Very Good condition.
Type of Finish: Anodized Black
Finish Originality: Original
Bore Condition: The bore is bright and the rifling is sharp. There is no erosion in the bore but there is some minor stubborn fouling throughout. In this writer’s opinion the bore rates 9/10.
Overall Condition: This rifle retains about 97% of its metal finish. There are moderate scratches and handling marks throughout. The action has light wear. The screw heads are sharp and the pins are undamaged. The markings are clear. Overall, this rifle rates in about Very Good condition.
Mechanics: The action functions correctly. We did not fire this rifle. As with all used firearms, a thorough cleaning may be necessary to meet your maintenance requirements.
Box, Paperwork & Accessories: 1x Magazine.
Our Assessment: The SIG 556 was developed as an American-market adaptation of SIG’s well-regarded SG 550-series rifle system, combining the Swiss-derived short-stroke gas-piston operating system with features intended to suit U.S. shooters. Unlike the original SG 550 family, the SIG 556 was configured to accept common AR-15/M16-pattern magazines and was offered in numerous furniture and sight configurations over its production life. This example is chambered in 5.56x45mm NATO / .223 Remington and features a 16″ barrel, A2-style flash hider, receiver-mounted Picatinny rail, and Swiss-style diopter sight arrangement with green fiber-optic inserts. Its adjustable polymer stock, ribbed handguards, and familiar magazine compatibility give it a distinctly Americanized configuration while retaining the piston-driven operating system that links it to SIG’s classic Swiss rifle family. This rifle remains in Very Good condition, retaining approximately 97% of its original metal finish. The exterior shows moderate scratches and handling marks throughout, along with light operational wear. The screw heads remain sharp, the pins are undamaged, and the markings are clear. The bore is bright with sharp rifling and no visible erosion, though minor stubborn fouling remains throughout, rating 9/10 in this writer’s opinion. The three-piece polymer furniture shows light scratches and scuffs but remains free of chips or cracks and rates in Very Good condition. The included 30-round steel magazine also remains in Very Good condition. Mechanically, the action functions correctly.
For collectors and shooters interested in SIG’s Swiss-derived rifle systems, the SIG 556 occupies an interesting position between the original SG 550 family and later American SIG platforms. Its short-stroke piston action, diopter-style sights, and overall receiver architecture preserve much of the character of the Swiss rifles, while AR-pattern magazine compatibility and American-style furniture make it substantially more practical for the domestic market. With its strong bore, high finish retention, useful sighting system, and included magazine, this is a solid example of one of SIG Sauer’s more distinctive U.S.-market semi-automatic rifles. -R.E.