Call Dave Kiff at PTG
He will give you the right chamber info for any bullet you are going to shoot. Assuming you buy the reamer from him, I guess.
At what ranges (distance) will you be shooting? Barrel length is important, depending.
For instance, I have a .123 in. freebore chamber (PTG reamer) in my 6.5x47 Krieger and am limited to 120 to 130 gr. bullets. Dave will tell you what you need for the 140 or 142 gr. bullets.
Keep us informed on your progress. There is a lot of great help here.
Roy