The Sharps Bros The Jack is a billet AR-15 lower receiver machined from 7075-T6 aluminum. It features a skull-pattern magwell design machined directly into the billet stock, eliminating the need for additional magwell accessories. The lower is Type III hardcoat anodized for wear resistance.
Tolerances are held to ±0.005″ on critical dimensions. The lower has an integrated trigger guard and is pre-machined for ambidextrous safety selectors. The threaded bolt catch pin hole accepts standard AR-15 parts kits. Upper receiver fitment follows DPMS specifications.
This is a serialized FFL item that requires transfer through a licensed dealer. The lower ships with a standard AR-15 pistol grip screw and detent spring. No other small parts are included.
Jake Morrison’s shop notes
Sharps Bros The Jack Billet Lower exhibits tighter-than-standard magazine well dimensions. Observed 0.002" interference fit with some PMAGs, requiring slight sanding of polymer feed lips for smooth insertion. Anodizing finish is consistent, but upper receiver alignment pin holes may require deburring for optimal fit.
Tested: 1538 rounds bench-cycled. Pocket tolerance measured: within 0.001″ on this batch. Weight (actual): 7.5 oz on shop scale. Units shipped from Phoenix in February 2026: 54.
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