Originally Posted by yooper77
It depends on the action not the brass. I have re-sized 30-06 Springfield into 8mm Mauser ammo for years, but I always stuck to manufacture loading data.
I currently reload my 338-06 A-Square with 30-06 Springfield brass. If I wanted a modern 8mm cartridge I would re-bore a 30-06 Springfield into a 8mm-06 because it just makes more sense. Easy reloading and less trimming, Ackley Improved cartridges grow less between firings, so an 8mm-06 Ackley Improved is a good choice.
That certainly makes sense (although in pistol calibers the brass does often have something to do with it,for instance 45 super brass is much more robust than 45acp,yet the external dimensions are identical),but it just seems to me that due to the extreme degree of similarity between an 06 and an 8mm to begin with,if a rifle can be re-chambered to 30-06 or 8mm-06,then it could take those same pressures even if the cartridge was left the same,while if a rifle could NOT take the pressures in its original 8mm Mauser form,then it would be unsafe to convert to either 06 and doing so would be asking for a face full of metal fragments.
This of course is all theoretical as,since the internal volume differs (although not as much as you would think if you throw the numbers into a calculator) you couldn't just use an 06 load in a 8mm and call it done and we have no way to measure pressures,although if I had no 8mm load data at all (like it was back in the day),I guess that's exactly what I would do,although I would start with a light load and work from there.
Its kind of interesting to consider what you would do if you had no 8mm components or data at all. My first instinct would be to get some 30-06,and take them apart and measure the powder charges. Id then try to make a die to swage the bullets to 323. Then re-size the case,put them all back together,with a reduce powder charge,at least until you figured out how much your max load would be,and you would have 8mm. I guess if I had to go through all that,a change that made it easier to put 06 cases in with minimal resizing might start sound really good.