If you're looking for load data, Pet Loads by Ken Waters has some pretty extensive info. What I remember reading is that's it's probably the most difficult round to reload for, think it has to do with odd size bullets!!?? If you like I could copy the pages and PM them to you. Glad you got to keep such a treasured piece of family history!!

After a little more research, the .22 HP is based on the .25-35 necked down, so you could make cases if you have to. Graf & sons has brass but finding a .227/228 bullet my be fun.