Llama Bob - With all due respect what you are saying is not grounded in physics at all. First the 348 Win holds 75 gr/H2O, while the 444 Marlin holds 69 gr/H20, by all accounts that 6 gr/H20, not 10 gr/H20. Second, the 348 Winchester has never operated on an 1886/71 action above SAAMI specified MAP of 40,000 CUP (41,000 CIP) same as the 33 WCF. It is regarded that the 1886/71 action can handle somewhat above 50,000 CUP. Your premise that the 348 Win operates at a higher pressure on a more stout action is just not true. The 444 Marlin operates at a SAAMI MAP of 44,000 CUP (45,000 CIP) and the 94 BB action is rated at 52,000 CUP and there are several Marlin rifles chambered in the 444 Marlin so they can handle the pressure generated by the 444 as well. The 444 Marlin is loaded to higher pressure simply because it projects less area and therefore less bolt thrust with a 0.514" diameter rim., while the 348 Win creates more bolt thrust due to its larger area from a 0.610 diameter rim.
Lastly your rational for stipulation that the 348 Win is more powerful by virtue of holding more powder does not take into account any real physics such as bullet diameter, bullet weight, hence TKO/stopping ability. How can the 348 Win be more powerful when it lags behind the 444 Marlin by a full 10 points with top loads (a 30 TKO vs 40 TKO on the 444 Marlin). That's like comparing a 300 Wby 200 gr. at 3,000 fps and a 358 Norma Mag 250 gr at 2,850 fps, the Wby holds 99 gr/H2O while the 358 Norma holds 88 gr/H2O. Is the Wby more powerful, well...no it has a TKO of 26, the 358 Norma Mag is at 36 TKO. Frontal area and bullet weight have a lot to do with the power of a cartridge. If they didn't why bother using 400 gr 416s and 500 gr 458s on cape buff and elephant, why not just use a 300 or 338 Magnum, reason is they lack stopping power, therefore not as powerful. Again I'm not sure what you mean by more powerful as it translates into ballistic and success in the game field, maybe I'm missing something. I realize the 348 Win is romanticized greatly because of the Win 71 rifle and it is a great cartridge but in reality is no more powerful than the 356 Win or 358 Win. Again no disrespect, just questioning your rational on the comparison.
