40-65: Learning what I can

[SgtDog0311]

Thanks for those Don. Appreciate you posting them. I think Kurt’s 44-75 Ballard reamer drawing was the first I spent any time trying to decipher. Thought it was a bottleneck at first.

Regarding Kurt’s, I’m wondering if I’m understanding it correctly to mean the .446 shown in ‘f’ to ‘e’ is the freebore. The chambercast he shows here http://historicshooting.com/mybb/showthr...p?tid=1369 seems to show that the transition used up that freebore but I’m not certain I’m reading it right.

On the two you posted I see enough difference in dimensions on case length and case mouth diameter to see why some say there are several 40-65 chambers, why some are tighter than others, and why some die sets might have to be altered for resizing.

If I'm reading yours right the Browning reamer gives you the 45 degree transition.