Has anyone made progress on a .620 rimless?

I am a bit afraid to go this route alone and was hoping to tag along behind a braver soul who breaks ground with a .620 rimless cartridge.

500 Grains,

I have just calculated that with the effort required to make a 620 rifle, plus the effort to get cases, dies etc. that the total effect of all that plus firing only one shot will be approximately equal to the recoil from firing 10,000 375s

Mike

500,
After my initial and foolhardy excitement I began to consider where I would put the necessary equipment to turn and swage the 50BMG brass to correct size. Not to mention scrabbling to the approximately $3-4,000 the rifle would cost, assuming nothing went wrong. Frank Wells gave me a quote not including woodwork of $3,500 complete. Add however much you want for a decent piece of wood and you get an idea.

P.S. I am in a physics class and I have found my professors pet interest is ballistics. I am going to be doing some interesting stuff this semester.