Its a wildcat. It is basically a WSM cut down to 1.8", necked up to .358, the Ackley Improved (very little body taper with a 40* shoulder).
We have some goofy restrictions here in Indiana with what we can hunt whitetails with. The law states that the case has to be 1.8" or less with a bullet diameter of .358 or larger. This fills the role real nice