Hi Jeff and Doc i am in the process of building it at the moment i am slowly getting the components togethor as i am on a limited budget so i have to sell things and save to do it right the first time. I spoke with J D Jones before i started the reamer design as he uses 60 degree shoulders on some of his chamberings and is having no troubles in single shot pistols and rifles with them. David Kiff also helped with the specifications Here my reamer soecifications on the shoulder .533, base .548, neck .369 length from base to shoulder 2.462, max case length 2.840, neck length .331 and loaded with a 300gr Sierra the OAL touching the lands should be 3.900" you could also go with a 15 thou body taper and a 40 degree shoulder if you were into an improved edge basicaly a 338-300RUM Improved. With the 60 degree shoulder i should have very minimal case streching on firing and it should be very stable i will be shooting the 300gr Sierra MAtchKings hopefully at around 3000fps in a 30" barrel.
Cheers Bill
Australia