Three 68mm cartridges:
6.5x68;
8x68S; &
10.75x68.

The 10.75x68 is a different case from the first two.

I have a Mauser M03 in 8x68S and 6.5x65mm RWS. I did want the 6.5x68mm but Mauser does not make an M03 barrel in that chambering.

Embarrassed to say I have not used either M03 barrel and worked up any loads yet!!! But have used my .222 Rem and .404 barrels for the M03 a reasonable amount so far.

I have used a 8x68S Mauser M98 borrowed from Karl Stumpfe to hunt on safari in Namibia and took warthog, gemsbok, hartebeest and springbok with it, as well as using my 9.3x74R for some of the animals, mainly some of the warthog from memory with the 9.3.

From this small amount of use, I liked the cartridge so decided to acquire one. My purpose in borrowing Karl's rifle was to try a 8x68S out in the field. It hot hard and well. I am looking forward to finally setting it up and using it a lot more later in the year.

And also seeing if the 6.5x65mm RWS can achieve close to similar ballistics to the 68mm. The 6.5x68 and also really the 8x68S in my opinion do need a longer barrel to fully utilise the large cases. My barrels I think are both 650mm or thereabouts. Need to measure them again to familiarise myself. A 26" or at least a 25" is the minimum I would go for.