SIG Sauer SIG516 Patrol 5.56 NATO AR-15, Short-Stroke Piston, Upgraded Geissele SSA Trigger & PWS FSC 556
Built for reliability and refined with high-end upgrades, this discontinued SIG Sauer SIG516 Patrol pairs a proven 4-position short-stroke piston system with a cold-hammer-forged 16-inch barrel rated for “over-the-beach” use. Factory-original parts are joined by a Geissele SSA two-stage trigger, a PWS FSC 556 hybrid muzzle device, and a Magpul MOE grip, giving the rifle a crisp trigger pull, reduced muzzle rise, and improved ergonomics while preserving the robust SIG design collectors look for.
Condition
Overall Condition: Very good condition, showing only light, superficial signs of prior handling or use.
Bore Condition: Good – Clean, well-maintained, minor wear marks.
Bore Rifling: Good Rifling – Intact, well-defined lands and grooves.
Specific Condition Notes: The receiver, handguard, and stock display a few small surface scratches and handling marks consistent with light range use. Finish remains uniform with no exposed metal, and the bore is bright with strong rifling.
What’s Included
- SIG Sauer SIG516 Patrol rifle with PWS FSC 556 flash hider installed
- Original SIG flash hider
- Geissele SSA two-stage trigger (installed)
- Original SIG trigger pack
- Magpul MOE pistol grip (installed)
- 1 Magpul PMAG Gen M3 30-round magazine
- Two SIG Sauer SIG516 owner’s manuals
The heart of this rifle is SIG’s piston-driven operating system, offering cleaner cycling and four gas settings—including a suppressed mode—for dependable function in varying conditions. Enthusiasts often seek the SIG516 for its HK416-style reliability in a civilian package, and the 20F serial prefix confirms U.S. commercial production between 2013 and 2016.
The factory cold-hammer-forged, nitride-treated barrel features a 1:7-inch right-hand twist that stabilizes the full range of 5.56 NATO and .223 Remington projectile weights. Threaded 1/2x28, it now wears a Primary Weapon Systems FSC 556, a hybrid flash hider and compensator that noticeably mitigates recoil and muzzle climb while maintaining flash suppression.
Shooter interface has been upgraded with a Geissele SSA two-stage trigger, delivering a 4.5-pound break for precise control, and a Magpul MOE pistol grip that enhances comfort and storage options. The collapsible six-position stock allows quick length-of-pull adjustments, making the rifle adaptable to body armor or varying shooting positions.
A free-floating aluminum Troy-style quad rail—factory-branded by SIG—provides uninterrupted top Picatinny rail space and ample real estate for lights, lasers, or optics. The 7075-T6 hard-coat anodized receivers, paired with the rail, form a rigid backbone that helps maintain accuracy and zero retention.