SixEight -
Great stuff - I think you absolutely may be on to something with the internal support for the swager. And the info you got re: the contour of the internal case head area is correct - a lot of different mfr's / caliber exhibitr this. Re: sawging - my knee-jerk is the same as your idea - cut 'em. I wouldn't waste the time and actually create more work for yourself.
On a side note - is it the picture or is that flash hole actually at an angle??