I have some White Power Punch's coming . 600 gr . For the .504
hopefully the weather is good in a couple weeks so I can give them a go . I'm actually concerned that they may be a little loose .
They probably will be too loose. Break out the bastard file. Nah, Muley a White will handle a 600 grain bullet nicely. (but I would rather let Chet shoot them )
Doc used to have loads listed with over 120gr of Pyro and those 600gr monsters. IIRC he talked about loads he shot with over 150gr of Pyro in the 54cal.