What is the difference between a 22 wildcat and 22 lr?

Answer 1

A .22 lr is an ammunition round commercially manufactured to particular specifications. A wildcat round is one which is produced according to someone's own design, but isn't in current production. Usually they will use a cartridge from a larger caliber, like the .308 win, neck down the top of it and insert a .243 sized bullet. That's how new types of ammunition are developed.