Used Sig Sauer SIG556 Classic 5.56 NATO 16" 556 SIDE FOLDER

Sig Sauer SIG556 556 Swiss 550 Pattern 55X Lineage

Sold On:August 6, 2026 at 9:30 PM
How Buying WorksEnded on August 6, 2026 at 9:30 PM

Key Features

  • Item Type: Semi Auto Rifles
  • Action: Long Stroke Gas Piston
  • Manufacturer: Sig Sauer
  • Capacity: 30 1
  • Model: SIG556
  • Barrel Length: 16"
  • Caliber: 5.56mm NATO
  • Finish: Black
  • Overall Condition: Good

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Product Description

    Sig Sauer SIG556 Classic 5.56 NATO Semi-Auto Rifle, 16-inch Threaded Barrel, Diopter Sights, Folding Stock

    This U.S.-made Sig Sauer SIG556 Classic combines a long-stroke gas piston action and a two-position adjustable gas system with a 16-inch threaded barrel and birdcage flash suppressor. It is equipped with diopter iron sights and a receiver-length top Picatinny rail on the upper receiver (no forward/top rail over the handguard), plus a right-side folding, skeletonized polymer stock that locks into a handguard catch. The rifle is compatible with AR-15/M16 (STANAG) magazines and includes one SIG factory 30-round magazine with coupling lugs.

    Condition

    Overall Condition: Good condition, showing some signs of prior use and handling.

    Bore Condition: Excellent - Clean, mirror finish, no signs of wear.

    Bore Rifling: Excellent Rifling - Sharp lands and grooves.

    Specific Condition Notes: There are scattered scratches and handling marks. The polymer dust cover has deteriorated. There is scratching on the ejection side consistent with normal operation.

    What's Included
    • 1x 30-round SIG Sauer factory detachable box magazine with side-coupling lugs

    The SIG556 Classic uses a semi-automatic, long-stroke gas piston system with an adjustable two-position gas regulator. It features right-side ejection and a design focused on reliable operation.

    The 16-inch barrel is threaded and fitted with a birdcage flash suppressor. This setup provides a standard 5.56 NATO configuration while maintaining a compact overall profile.

    Sighting is via a hooded post front on the gas block and a rotary diopter drum rear. A receiver-length top Picatinny rail on the upper receiver (no forward/top rail over the handguard) provides mounting for compatible accessories.

    The black polymer, right-side folding skeletonized stock latches into a handguard catch when folded and provides a 13.0-inch length of pull. A two-piece polymer ribbed handguard completes the classic configuration.

    Construction pairs a machined aluminum-alloy upper receiver with an integral 1913 rail with a forged aluminum lower. The rifle accepts AR-15/M16 (STANAG) magazines, and it ships with one SIG Sauer factory 30-round magazine that includes side-coupling lugs. Stated capacity is 30+1.

Specifications

Item TypeSemi Auto Rifles
ManufacturerSig Sauer
ModelSIG556
SubmodelClassic
Caliber5.56mm NATO
Overall ConditionGood
Bore ConditionExcellent
ActionLong Stroke Gas Piston
Capacity30 1
Barrel Length16"
FinishBlack
Sight/Opticdiopter iron sights
Country of OriginUnited States