ITS ALL IN WHAT THE FIRE ARM CAN HANDEL THERE ARE A LOT OF OLD 8MM OUT THERE SO SAMMI LIMITS WHAT US MANUFATURES CAN LOAD THE ROUND TO. SAME WITH OLD 45-70, 30-30,S ETC. A 8MM MAUSER ON A POST 98 ACTION CAN BE LOADED AS HOT OR HOTTER THAN A 30-06. IT JUST TAKES MORE POWDER. YOU WILL ALSO SEE EXAMPLES OF DIFFERANT VELOCITEYS FOR A SAME WEIGHT BULLET WITH THE SAME CHAMBER RPRESSURE. THIS IS BECAUSE ALTHOUGHT THE PRESSURE IS THE SAME IT IS FOR A LONGER PERIOID OF TIME. TAKE A 300 SAVAGE VS A 7.62X39 SAME BASIC PRESSURE ( CLOSE) BUT THE 300 SAVAGE CAN OUT DUE THE X39 BY CLOSE TO 300 FPS DUE TO THE LARGER CASE CAPACITY AND LONGER BURN TIME OF THE POWDER. THAT MY THEORY ANY WAY.
I am not new nor am I experienced at all factors regarding this topic. But something that always made me curious is the pressures of some cartridges being higher than others. 30-06 is higher than 8mm, which is roughly that of the 7.62x54r which is lower than a 7.62x39. Is it the type of powder? This might seem silly to some, but the varying size shells not necessarily having pressures with any correlation to each other is confusing.
HMMM I DISAGREE HERE. WHY FOR GODS SAKE WOULD YOU WANT TO GO THROUGH ALL THE TROUBLE OF CUTTING ANDS REFORMING BRASS WHEN YOU CAN SIMPLY JUST USE A .311 BULLET IN A 308 WINCHESTER CASE????????????????????
Since the kit has the finned .311 barrel, the logical choice is 7.65x53 Argentine Mauser. Just a bit longer than a .308, less pressure, fits M14 and G3 .308 magazines, probably others too; those are what I had on hand to check with.
You have to buy bulk brass from Graf or cut down .30-06 brass, but you use the same .311 bullet as the 7.62x54R or .303 British.
Reamerrentals.com has the 7.65 reamer for rent, if I remember right.
If you just want to blaze through a few boxes of ammo and leave the empties for someone to pick up, you probably won't want to shoot 7.65. Otherwise, it costs the same as reloading for 54R.