Geissele Automatics Super Duty Stripped Lower Receiver

$175

Standard AR-15 lower for all five calibers. 7.62x39 steel mags can bind or fail to lock back in some magwells; an enhanced bolt catch or specific mag brand may be needed. .450 BM uses dedicated straight-wall mags that fit a standard magwell.

Build with this part

Opens the builder with this part fitted. Other parts change only if they have to.

Pros and cons

Pros

Forged 7075-T6 with Type III hardcoat
Same lower used on Geissele Super Duty rifles
Safe/Fire markings on both sides

Cons

No upper tension screw
Mil-spec controls, no ambi features
Heavier than most forged lowers (9.7 oz)

Other lower receiver options

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Centurion Arms CM4 Forged Stripped Lower Receiver $135
Palmetto State Armory Sabre-15 Ambi Lower Receiver $100
Griffin Armament Mk2 Ambidextrous Stripped Lower Receiver $220
American Defense Manufacturing UIC Ambidextrous Stripped Lower Receiver $370
Radian Weapons AX556 Ambidextrous Lower Receiver $450
Aero Precision AR15 Gen 2 Stripped Lower Receiver $120