The dimensions of the chambercast aren't the dimensions of any cartridge. Chambers must be larger than the cartridges intended for them, otherwise, they wouldn't enter the chamber. How much larger? is the question. Modern chambers may be .015" larger in diameter, at the head. The difference between "Go" and "No Go" headspace gauges for 06 length cartridges is .006" and for 308 length it is .003". Bullet diameter now is usually the same as groove diameter. None of this holds for old black powder cartridges. Bullets in black powder cartridges were lead and smaller than groove diameter, usually even smaller than bore diameter. They "bumped up" in firing( when black powder is the propellant) to fit the barrel. This allowed room for the cartridge to chamber, even with black powder residue in the barrel. With all this said, a couple different cartridges could have been intended. One is the 10.15x62.5 R Serbian Mauser, with a 10.22mm dia. bullet. This was a military cartridge, but enjoyed a little popularity for hunting. The other is the 10.25x60R mm(DWM 49), also known as 10.2X60R Schutzen, with it's 10.43mm dia. bullet. While shown as a target cartridge, it is plenty large enough for hunting. In my considered, but unlearned, opinion; the most likely one is the 10.2x60 R Schutzen. Commercial cartridges were more likely to be used than military. As to what Raimey alluded to, above, it doesn't matter if you can't precisely name the cartridge. The Mall Mart is not going to have any in stock, anyway. You can make, or have made, both cases and bullets; that is what matters.
Mike
