Geissele Automatics GDP-556 AR-15 Pistol, 5.56 NATO, 8-inch Barrel, Free-Float M-LOK Handguard, Ambidextrous Controls, Matte Black
This Geissele Automatics GDP-556 is an 8-inch, 5.56 NATO AR-15–pattern pistol from the Geissele Defense Pistol series. It stands out with ambidextrous controls, a free-float aluminum M-LOK handguard with a full-length 1913 top rail, and a PDW-style dual-rod brace. It is in excellent overall condition with a clean, mirror-bright bore.
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: There are minimal signs of prior handling, and the bore is clean and shiny.
What’s Included
- 1x 30-round Magpul PMAG polymer AR-15 magazine
- Geissele Automatics factory box with GDP-556 model label
- Geissele Automatics owner's manual
The GDP-556 pairs an 8-inch 5.56 NATO barrel with a direct-impingement, semi-automatic action for compact handling. The factory carton label shows Model GDP-556, Type PISTOL, Barrel Length 8", Caliber 5.56MM, and Serial Number GDP556-20290.
The upper receiver is forged-style and includes a forward assist, shell deflector, and ejection-port cover. A free-float aluminum M-LOK handguard runs a full-length 1913 top rail with T-marks and integrated QD sling sockets for sling placement and accessory spacing.
Controls are set up for versatility: an ambidextrous safety, a right-side ambidextrous magazine release with a raised G marking, and an extended, textured bolt catch. The ambidextrous charging handle uses skeletonized latches for positive purchase.
A threaded muzzle hosts a multi-port muzzle device installed at the factory. The pistol wears a PDW-style dual-rod arm brace with a textile strap and a Geissele-branded polymer pistol grip. The matte black finish is consistent across the receivers and handguard. Made in the United States.