Geissele Super Duty Stripped Lower Receiver, Black 5.56

The Geissele Super Duty Stripped Lower Receiver in black — a precision-forged 7075-T6 aluminum foundation for AR-15 builds that demand more than mil-spec minimum.

• 7075-T6 aluminum forging: same alloy grade specified for military M4A1 lower receivers, machined to tighter tolerances than standard mil-spec
• Type III hardcoat anodize in matte black: MIL-A-8625 Type III finish for abrasion and corrosion resistance
• Nylon-tipped tensioning set screw: eliminates upper-to-lower play without permanent modification
• Geissele roll-mark and markings: includes safe/semi/auto selector markings and serial number engraved at the factory

The Super Duty lower is Geissele’s answer to the gap between generic mil-spec forgings and custom billet receivers. The forging starts as the same 7075-T6 aluminum alloy used in military-contract lowers, but Geissele machines it to their own dimensional spec — tighter than TDP minimum on the mag well, trigger pin holes, and takedown pin bores. The result is a receiver that locks up to a mil-spec upper with noticeably less slop than a typical commercial forging.

The Type III hardcoat anodize is applied at a thickness that meets MIL-A-8625, giving the receiver a uniform matte black finish that resists wear from sling hardware, range bags, and general handling. The integrated nylon-tipped tensioning screw at the rear of the receiver allows the builder to remove any remaining wobble between upper and lower — a detail borrowed from Geissele’s Super Duty complete rifle line.

The receiver ships stripped — no fire control group, no buffer assembly, no grip. Compatible with any mil-spec AR-15 lower parts kit. Chambered marking is 5.56 NATO. Multi-cal or 5.56-marked variants are available depending on production run.

We stock these because builders keep asking for them — the Super Duty lower is one of the few forged receivers that competes with billet fit without the billet price tag. Add to cart and build it right.