27 CFR § 479.141
Stolen or lost firearms
April 24, 2020
Whenever any registered firearm is stolen or lost, the person losing possession thereof will, immediately upon discovery of such theft or loss, make a report to the Director showing the following:
(a) Name and address of the person in whose name the firearm is registered, (b) kind of firearm, (c) serial number, (d) model, (e) caliber, (f) manufacturer of the firearm, (g) date and place of theft or loss, and (h) complete statement of facts and circumstances surrounding such theft or loss.