Geissele Automatics Super Duty SD-556 Lower Receiver (5.56mm NATO) — 7075-T6 Forged, Type 3 Hardcoat Anodized
The Geissele Automatics Super Duty SD-556 lower receiver is a mil-spec compatible AR-15 pattern lower, precision machined from a 7075-T6 aluminum forging and finished in Type 3 hardcoat anodize. Markings include SAFE/FIRE indicators and a CAL 5.56MM designation.
This lower is configured with an Atrius Forced Reset Selector and an ALG trigger, and is assembled with a receiver extension (buffer tube) and pistol grip installed.