I have an old Springfield rechambered in 30-06 ICC or CCC, as the stampings have been almost totally sanded off.
It is a very good rechamber job and has a real nice crush fit, just need some information on it.

-Spencer

ICC stands for Improved cartridge combustion...according to PO ackleys handbook.....it is a case a bit like the .30 Gibbs....a bit less capacity and a longer neck than the Gibbs..This wildcat CANNOT be fireformed like an Ackley improved (fire the parent case..volia AI version) You must form a false shoulder then fireform..best thing in your case is to get a cast of the chamber and go from there

I can recall seeing it in a book once.
The shoulder on it is at like an 85 degree angle, very abrupt but not crisp and sharp.
The shoulder is 'scooped' looking as it gradually goes from body to neck and is not steep at all.
I would assume it is ICC but like I said before, almost all the markings are sanded off.
BTW, it fireforms well with regular 30-06 ammo.

-Spencer