I believe the 6.5x68 suffered from having factory barrels with a two slow twist rate. Maybe that 1 in 12 was normal? It was promoted with RWS ammunition of a 93 gr SP at 4,000 fps. For chamois. Also 127 gr KS ammunition.

I think the natural bullet weight range for the 6.5s for medium game lies between 120 grs and 140 grs. With 160 grs being a heavier beast bullet though it was a traditional round. I'd give 90 to 100 grs a go in my 6.5x65 RWS and if I had a x68 for speed. If suitable bullets were available I'd hunt lighter medium game with them. A 120 to 127 gr bullet is more sensible.