Thank you for the information on the swiss sig. There is no ammo with the gun, and the 93 year old, who had accidentally discharged it the last two time he handled it, had his wife dispose of all of the ammo. Is this a 9mm or some other caliber?

Yes, the P75 was chambered in 9mm Parabellum (aka 9x19mm, aka 9mm Luger, aka 9mm NATO, etc.).

Why not ask the question in the already open thread on this same gun?