Yes, the chambers can be excessively long. I started off with one having .019" excessively long body of the case.
I necked new RP 8mm Mauser brass straight, then down to hold a 9.3mm bullet for a crush fit on closing the bolt.

This is the same method I use with .30/06 brass to make my .375/06 IMP brass.
Because of this method, there is very little fireforming to do, as the case's shoulders are almost perfect after the necking operation.

My 9.3x57 Model 46 also had a .370 groove diameter but the largest bullet dia. that could be chambered was .367".
Even 286gr Privi's at .365" shot into sub 1" groups at 100 meters, as did the 225gr. sized down to .367" Hornady, 232gr. Norma Vulcan,
270gr. Speer, 293gr. TUG and 300gr. sized down to .367" .375 Hornady RN's, both bonded Interbond and Interlocked.
My bro has that rifle now and is using Norma Alaskan 286gr. RN's I have loaded to 2,200fps mv.