Example 1 to paragraph (c)-Frame or receiver: A frame or receiver parts kit containing a partially complete or disassembled billet or blank of a frame or receiver that is sold, distributed, or possessed with a compatible jig or template is a frame or receiver, as a person with online instructions and common hand tools may readily complete or assemble the frame or receiver parts to function as a frame or receiver.
Example 2 to paragraph (c)-Frame or receiver: A partially complete billet or blank of a frame or receiver with one or more template holes drilled or indexed in the correct location is a frame or receiver, as a person with common hand tools may readily complete the billet or blank to function as a frame or receiver.
Example 3 to paragraph (c)-Frame or receiver: A complete frame or receiver of a weapon that has been disassembled, damaged, split, or cut into pieces, but not destroyed in accordance with paragraph (e), is a frame or receiver.
Example 4 to paragraph (c)-Not a receiver: A billet or blank of an AR-15 variant receiver without critical interior areas having been indexed, machined, or formed that is not sold, distributed, or possessed with instructions, jigs, templates, equipment, or tools such that it may readily be completed is not a receiver.
Example 5 to paragraph (c)-Not a receiver: A flat blank of an AK variant receiver without laser cuts or indexing that is not sold, distributed, or possessed with instructions, jigs, templates, equipment, or tools is not a receiver, as a person cannot readily fold the flat to provide housing or a structure for the primary component designed to block or seal the breech prior to initiation of the firing sequence.
27 C.F.R. §478.12