Drilled and Tapped
A receiver with threaded holes for mounting accessories — typically scope bases on a rifle.
Drilled and tapped describes a rifle receiver that has been machined with threaded holes (usually 6-48 or 8-40 UNF) for attaching scope bases or rings. Modern bolt-action rifles and many semi-autos come drilled and tapped from the factory; older and surplus rifles often require gunsmithing to add the holes. Once D&T’d, the rifle accepts the wide ecosystem of scope mounts.