M1 Garand in.308 (no, it's not my personal defense
weapon, it's 30 - year old USGI surplus that I use at Regional CMP (civilian
marksmanship program) events.
Add in ammunition, extra clips, accessories to carry safely, and training not only in
weapon basics and
marksmanship, but ALSO for crisis response, active shooter response, close quarter combat tactics, target recognition, and how to coordinate with law enforcement response.