SIG Sauer SIG556 Classic 5.56 NATO Semi-Auto Rifle, 16 in CHF Threaded Barrel, Folding Stock, Diopter Sights, 30+1
The SIG Sauer SIG556 Classic is a U.S.-made, short-stroke gas piston rifle with Swiss 551-style features and practical ergonomics. This example pairs a 16-inch cold hammer forged, threaded barrel and 1:7 twist with robust iron sights and a folding, skeletonized stock. It accepts AR-15/STANAG magazines and includes a two-position adjustable gas regulator for reliable operation with different loads and conditions.
Condition
Overall Condition: Good condition, showing some signs of prior use and handling.
Bore Overall Condition: Excellent - Clean, mirror finish, no signs of wear.
Bore Rifling: Excellent Rifling - Sharp lands and grooves.
Specific Condition Notes: There are markings from previous handling and use. Red paint is present near the front of the rifle and on the barrel. Please refer to the photos for a close look at these areas.
What’s Included
- 1x 30-round Magpul PMAG polymer AR-15 magazine with MagLevel window
The SIG556 Classic uses a semi-automatic, short-stroke gas piston system with a two-position adjustable gas regulator. It features a right-side, reciprocating charging handle and a manual safety, along with a charging-handle slot cover.
Its 16-inch cold hammer forged barrel is threaded at the muzzle and cut with a 1:7 twist. This configuration supports common 5.56 NATO loads while offering durability and straightforward suppressor or muzzle device compatibility.
Iron sights include a steel diopter rear with a 100/200 elevation drum and a gas block-mounted front sight. The receiver provides an integral 1913 Picatinny top rail for adding optics; no separate scope mount is included.
Ergonomics and handling are classic 551-inspired: a Swiss 551-style ribbed, two-piece polymer handguard; a folding, skeletonized polymer stock with a 12.5-inch length of pull; and a ribbed SIG-pattern pistol grip. The rifle accepts AR-15/STANAG pattern magazines and has a 30+1 capacity.
Construction details include a stamped steel upper receiver, an aluminum-alloy lower, and U.S. manufacture. The receiver is rollmarked "SIG SAUER INC., EXETER, NH, USA."