SIG Sauer SIG516 Gen 2 PRO 5.56 NATO, 16-inch, Short-Stroke Piston AR-15 Rifle with Quad-Rail and Flip-Up Sights
The SIG Sauer SIG516 Gen 2 PRO stands out as a piston-driven AR-15 with a four-position adjustable gas regulator, a chrome-lined 16-inch barrel, and a robust free-float aluminum quad-rail. This example comes from the discontinued SIG516 line and features forged 7075-T6 receivers with a hard-coat anodized finish, flip-up iron sights, and an A3-style flat-top upper. It includes the original factory box with a matching label.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: There are a few minor scuffs and scratches with light finish wear. The installed CompMag brand magazine is fixed in place in a CA-compliant style.
What’s Included
- Original SIG Sauer factory box with matching label (model WR516G2-556N-16B-PRO)
- Assorted small parts in plastic baggies (as shown)
- SIG Sauer safety/instructions card with QR code for operator manual
- CompMag brand magazine installed
This Gen 2 PRO uses SIG Sauer’s short-stroke gas piston system with a four-position adjustable gas regulator, delivering clean operation and tunability. The barrel is rollmarked 5.56 NATO and is chrome-lined for durability.
The 16-inch barrel is threaded and fitted with an A2-style birdcage flash suppressor. The free-float aluminum quad-rail provides a continuous T-marked top rail with numbered side and bottom rails for precise accessory placement.
Forged 7075-T6 aluminum receivers wear a hard-coat anodized finish. The magwell carries the SIG circular logo. The rifle includes a collapsible stock with a 12.25-inch length of pull and a SIG SAUER-branded polymer pistol grip.
The A3-style flat-top upper includes a forward assist, case deflector, and ejection-port cover. Flip-up front and rear iron sights are installed. The rifle has a 10-round capacity with the fixed CompMag installed. The factory box label matches the receiver serial.