Thanks ever so much for your reply and you are correct in that I need some help. I have been loading for BPC most of my life but this is unlike anything I have ever come across. It is s virtually new H & H paradox, cased, SN 11905 and has the original Holland label and loading paper in the top section. The loading label says it is a 3 1/4 nitro Magnum regulated for 4 3/4 drms Curtis and Harvey BP or 100 Gr of Cordite. I have shot in the past a few Remington 3" Magnum shells out of it but it is wicked. I would say it kicks about twice as hard as my Evans 577 3". I am at a loss as to whether to use 3" Rem paper hulls with a shotgun primer or use 2 1/2" brass 12 Ga shotgun shells with a boxer large rifle primer. My big concern is all the space in that shell as the loads that I seem to see are going to need some sort of filler to keep the small amount of powder down at the primer. Got any suggestions?
Don Swainbank