The rifle used as a standard 98 Mauser opened up for magnum rounds, magazine and bolt face & just a bit ar the head end of the magazine. This was around 1986 or so. This is not a standard wildcat chamber & I believe it's an annomoly- but - dies are now available.
: The first rifle barrel I chambered used a bushed 6.5x68 reamer plunged deeper by .150" for a proper body length & neck length + a .375 neck/throat reamer to finish it. I cut the chamber by hand. An 8X68 reamer would have been better to properly position the shoulder, but the method I used worked fine. I shot the rifle for a while, doing more load developement than hunting and only shot one moose with it. It had about the same peformance as a .375H&H IMP., a 270 HornSP at 2,850fps. It worked find, but the bullet was a bit soft for that velocity.
: I sold the original rifle to a friend, who had Huntingtons make him up a set of dedicated dies. I'd used (and kept) the dies I'd modified for my loading. Keith shot the rifle for about 2 years (about 6 or 7 moose killed with it), then gave it to his brother who shot it for a couple years & re-barreled to the same 9.5X68, having Bevin King make and chamber the barrel for him.
: Both Keith and his brother Dave, developed loads to 2,900fps with 270gr., 2,700fps with 300's and over 3,000fps with 235's. I did try some Barnes 350's at around 2,500fps. Recoil was still OK an 8lb. rifle.
: Brass mostly has been 8x68 RWS, but it is hard to come by around here. Best for us has been to use .375H&H brass, turn the belt to .522" and fireform. Seems to me it is the same length case but might be a bit shroter than .375H&H brass. I might just have a case or two around here if you want me to send you one. It is nice to have such a big thumper in a rimless case. BTW, ..375 brass forms perfectly and takes the same loads as RWS brass for about identical performance. WW H&H brass has up to 2gr. more capacity, but is not as strong as RWS brass, so they even out in speed pretty much.
: With an 8X68 chambering reamer and 9.3 neck/throat reamer, a 9.3X68 cahmber could easily be cut, but then, the 9.3X64 is a pretty good round itself.
: If any further questions, you can contact me at dtlc@telus.net
: Incidently, this barrel started life as a .375/06IMP and after some 2,000rounds, became the 9.5X68. After going through 3 owners, it returned to me, full 24" long and magnaported. The rifling was a memory for about 6", so I shortened it 2" and re-chamberd with a bushed .300 WM reamer, held back for a 2" maximum case length. This resulted in a .375/350RemMag chambering, and still shoots into 1 1/2" same POI for 235, 270, 285 and 300gr. bullets.