Drill cartridges, adaptors, and methods for multi-caliber drill cartridge training

An adaptor assembly for transforming a caliber specific drill cartridge for use in a first firearm chamber into a caliber specific drill cartridge assembly for use in a second firearm chamber the adaptor assembly comprising;

• a drill cartridge with a first central axis which comprises
• a rear casing, and
• a front casing with a first maximum outer dimension perpendicular to the first central axis, the front casing being connected to the rear casing such that the front and rear casings cooperate to form a housing, the housing being configured and dimensioned for chambering in a first firearm chamber;
• and
• a cartridge specific adaptor with a second central axis which comprises
• a cylindrical member with second maximum outer diameter which comprises
• a front end,
• a rear end,
• a first passage extending from the rear end toward the front end, the first passage being bound by a first inner surface,
• a second passage extending from the front end to the first passage, the second passage being bound by a second inner surface, and
• an end wall adjacent the second inner surface;
• the adaptor assembly being a combination of the drill cartridge and the cartridge specific adaptor such that the end wall is disposed between the front casing and the rear casing, the second inner surface and the front casing define an annular space, and the adaptor assembly is configured and dimensioned for chambering in a second firearm chamber.