This got me thinking so I did some research. The RCBS and Hornady dies both have the 40 degree shoulder. I lucked out in that both of my K-Hornet rifles, bought many years apart also are chambered for the 40 degree shoulder.
There seems to be some confusion over the shoulder angle and the designer of the round. Some say the 40 degree shoulder version is really the .22 Ackley Hornet. I don't know for sure but I'm glad I know now so that if I decide to get another, I'll know what reamer to ask for...
BTW, I remember years ago asking a gunsmith about the fired cases from my rifle not matching some K-Hornet cases I bought at a gun show. For what it's worth, he told me that the version my gun has is the most popular of the several versions that are out there. I didn't press for any more info...
Tony