I've ordered a 6BR, 14 twist Shilen barrel, 24" varmint for a Savage rifle. I'll be using Berger 68gr flat based target rounds. I'm required to send 4 dummy rounds with the correct OAL to Shilen for chambering but don't know the OAL needed. I'm thinking I'll need .030 or so for possible jump if needed . Any advice is greatly appreciated. Thanks