Geissele Super Duty SD-556 5.56 NATO AR-15 Rifle – DDC Finish, 16-Inch CHF Barrel, SSA-E X Trigger
The Geissele Super Duty SD-556 delivers a factory-built AR-15 that marries hard-use durability with match-grade precision. Built around a cold-hammer-forged, chrome-lined 16-inch barrel and Geissele’s proprietary mid-length “Super” gas system, this rifle is tuned for reliable cycling under demanding conditions. A DDC (Desert Dirt Color) Type III hard-coat anodized finish covers the forged 7075-T6 receivers and 15-inch MK16 handguard, giving the platform both corrosion resistance and a distinctive look.
Condition
Overall Condition: As-new condition with no signs of prior handling beyond what’s typical from inspection.
Bore Condition: Excellent – Clean, mirror finish, no signs of wear.
Rifling Condition: Excellent – Sharp lands and grooves.
What’s Included
- Geissele Super Duty SD-556 rifle
- 1× 30-round Magpul PMAG Gen M3 polymer magazine
Geissele’s 16-inch 4150 CMV barrel is cold-hammer-forged for strength, chrome-lined for longevity, and capped with a pinned and welded SureFire closed-tine flash hider on 1/2-28 threads. The pinned & welded setup secures the device permanently and keeps the overall length within compliance.
The heart of the rifle is a Stressproof bolt forged and proof-marked with a stylized “G.” Rated to 115,000 psi and treated with Nanoweapon coating, this bolt is engineered for extreme round counts while resisting wear and corrosion.
Shooters benefit from Geissele’s SSA-E X two-stage trigger featuring a flat Lightning Bow shoe and a crisp 3.5-lb break. An ambidextrous selector, maritime bolt catch, and checkered ambidextrous magazine release round out a fully ambi control set.
The 15-inch Super Modular Rail MK16 is machined from 7075-T6 aluminum and provides full-length M-LOK slots plus an uninterrupted 1913 Picatinny top rail for mounting accessories. Combined with the adjustable B5 Systems Bravo stock and a 14-inch length of pull, the rifle balances agile handling with solid cheek weld and recoil management.
Finished in Geissele’s signature Desert Dirt Color and carrying the SD556- serial prefix that denotes a complete Super Duty production rifle, this example shows no use beyond the factory test fire and inspection.