40-65: Learning what I can

[SgtDog0311]

Regarding the generous diameter of the Browning case mouth and free bore I notice the Winchester reamer diagram eliminates .003 at the case mouth and is .0015 smaller in the freebore at .4085. So if you had a .408 groove size, then the free bore diameter would not allow much over groove at all. That makes me think if you flattened the transition to take up nearly all the free bore or just did the same thing with a throat reamer you’d be fine.

Question for you Kurt that I’ve thought to ask more than once. At one time you made note of the original cast of an 1877 #1 Sharps having a 3.5 degree chamber end, and that you changed it to a 5 degree - but wished you’d have left it original. Is that wish due to performance or just staying true to the original? Just curious! I recall seeing some of the so called “match chambers” of ‘old dead guys’ that had 3.5 degree, so got me to wondering.

Also see that a modern SAAMI specs call for the 38-55 chambers to have a 6 degree. I’m wondering if there would be any harm having a 40-65 Winchester reamed so as to take up all the freebore with whatever angle transition that would work out to? That would look a little like your cast you corrected the oval with… was not much free bore left there after you applied that “fix”.