P Flados
Member
About a year go I was making up a big batch of 300 BO from mixed 223 brass and other "reject" cartridges made from 223 brass. Some of the brass I was converting had been fired in a wildcat chamber that was a little big down at the base. These took a lot of force to size and a few sheared off the rim when trying to extract the case from the sizing die. I remembered the base size match on 357 and tried running the problem cases through my 38/357 carbide die first. They ran in and out of carbide die easy enough and then they were very easy to get in and out of the 300 BO sizer.