webcicle yes there was a Remington 22"JET" cartridge but the case is tapered at it goes up to the bullet. It doesn't have the shoulder like the case in question does.It's been a long time since I saw a 22 Jet but I remember how the case looked. I would say it's a military round by the headstamp. The question is what has it been made into. I'm sure it some kind of wildcat cartridge made from a 223. Ruger Redhawk