The new .375 Ruger is based on the 8x68 case. I built one up back in the late 80's or early 90's and worked up loads for it aztthat time. We called it the 9.5x68. It has identical case capactiy to the .375H&H when using .375H&H brass to form cases and duplicates the .375 ballistics at the same pressures. With RWS brass it is capable of running 270gr. at 2,900fps+ with top-end loads and light deer bullets of 235gr. at well over 3,000fps, maybe 100fps advantage, real or imagined. When my stock of RWS 8x58 brass ran low, I simply turned the belts of .375H&H brass down to .522", then trimmed to length and fireformed. Once formed, they worked perfectly and saved on the price of the expensive European brass.
: My rifle was a 1935 VZ BRNO Mauser and it worked perfectly. I sold the rifle to a friend, who then shot many moose with it, and sold it to his brother who loaded 250Barnes "X" and shot many more moose with it. All in all, the first barrel, a McGowen, started life as a .375When Imp, had over 8,000 rounds through it, maybe even 10,000 when it was retired.
: When the rifling was a memory for about 6" a new barrel was fitted and chambered using the same 6.5x68 reamer and neck/throater that was used originally by me. RCBS makes the dies and has had them since Keith (second owner) first ordered them made back in '88 or whenever it was I sold it to him. Dave, Keith's brother, gave me the old barrel. I shortened it and chambered it to .375/.350Rem for testing that ctg. and it still shot 1-1/2" at 100 meters although with it being 1" shorter, it still didn't have any visible lands for about 3". Dave had it Magnaported & the noise didn't seem louder to the shooter, but was somewhat, I guess. Muzzle jump was almost eliminated, though. This might have been in the early 90's, I don't remember exactly. It's an incredible round, beautiful to look at and nice to use since there is no belt on the 8x68 brass.
: With the belts turned off .375H&H brass, the case head above the belt expands out to the head diameter of .522" and looks just fine. In function, it is as safe as any normal brass. RWS brass is stronger than any of the .375H&H American made brass, though. Identical loads showed .001" less expansion on the expansion ring. The .522" dimension turned on the belt is necessary to hold the H&H case properly in the chamber as that is the .375 Ruger(9.5x68)head diameter. Turning the belt down is a 10 second job on a lathe but could be done with the brass chucked in an electric drill held in a bench vise, with files. One should have a michrometer or dial calipers to get the belt the correct dimension.
: Wonderful round, - will it surplant the H&H - who cares. It's an excellent ctg. that works in standard Mauser actions and gives real world power. With the variety of good .375" bullets on the market today, it's sure to be a winner for those who appreciate great ballistics.