Sig Sauer SIG551-A1 Classic 5.56 NATO Semi-Auto Rifle, 16 in CHF Barrel, Folding Skeleton Stock, Diopter Sights, 1/2x28, Excellent
This SIG Sauer SIG551-A1 Classic stands out with its long-stroke gas piston system, cold hammer forged 16-inch barrel, and classic 55x-series configuration. It features a right-folding skeleton stock, rotary diopter sights with a hooded front post, and an integral receiver Picatinny rail. Marked with the Exeter, NH rollmark, it includes three SIG 55x-pattern translucent magazines and the factory owner's manual, and is in excellent condition.
Condition
Overall Condition: Excellent condition, showing only faint signs of any prior use or handling.
Bore Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: This rifle shows minimal markings from previous handling and use. Please refer to the photos for detailed views of the exterior surfaces, controls, and furniture.
What's Included
- SIG Sauer SIG551-A1 owner's manual
- 2x 30-round SIG 55x-pattern translucent polymer magazines with integral coupling lugs
- 1x 20-round SIG 55x-pattern translucent polymer magazine with integral coupling lugs
The SIG551-A1 Classic uses a semi-automatic, long-stroke gas piston operating system with an adjustable gas regulator featuring a knurled collar. Controls include a right-side reciprocating charging handle, an ambidextrous two-position safety, and a paddle-style magazine release. It accepts SIG 55x-pattern proprietary magazines, matching the included translucent polymer mags with coupling lugs.
The 16-inch cold hammer forged barrel is threaded 1/2x28 and fitted with a multi-prong flash suppressor. It features a 1:7 twist to stabilize a wide range of 5.56 NATO projectiles and retains a bayonet lug. The barrel is rollmarked "5.56 NATO 1/7 P."
Sighting equipment includes a hooded front post and a rotary diopter rear. The receiver integrates a MIL-STD-1913 Picatinny rail for mounting compatible accessories. Classic ribbed polymer handguards are vented for heat management, and sling loops are provided front and rear.
Construction pairs a stamped steel upper (with a riveted guide rail) and a forged aluminum lower for durability. The right-folding polymer skeleton stock locks via a hinge latch and offers a 13.25-inch length of pull. Receiver rollmarks read "SIG551A1, 5.56 NATO, SIG SAUER INC., EXETER, NH, USA," associated with pre-2016 SIG production. Overall length is approximately 36.1 inches extended and about 26 inches folded, with an unloaded weight around 7 pounds (without magazine).