Swadiver , do yourself a favor and read an article by the title of A poor man's hammer on 6mm br , I was in the same boat several year's ago and followed his reamer print from PT@G , Dave will know what reamer it is , and my gun turned out to be a Hammer with 70 grn, NBT and I am now shooting 105 Nosler CC through it and it's ridiculous accurate , I will use this reamer for the rest of my life on builds , it just flat out shoot's in my 1-8 twist brux , now if I could just get some brass for it ?
No reason to reinvent the wheel , just food for thought .