I am not sure which end of the cylinder you are calling the entrance
and exit. The cylinder holes on all revolvers have to be tapered in
order to easily extract the brass after it has been fired. I bet the
higher power cartridges that are rather long have more taper. Check a
44 mag. and see how much taper they have.

Don't bother measuring the cylinder. Measure the brass after it has bee
fired. Should show the identical taper. Now I am curious about the
taper in my 22 mag. cylinder. Have to go fire it and check the brass.

Paul