I was thinking to cut the brass down to 73mm and then ram it into a .450/400 3,25” die. Isn’t that enough cut the die shorter to sqeeze the neck even further down untill the case enter the chambers freely. Fill the case up with bp and shoot a .41” round ball to just fireform. From here I can get a toolmaker overhere to make some simpel dies and a fixer. It doesn’t have to be science....or ofcouse to commit the ultimate sin...ream the chambers up 450/400 3,25”....Problem solved and from here the world lay open