Yes , A new round with new specs. not a redo . A new gun with new round .
I get it. I have been thinking about this from the day you posted it. You want to take today's technology to make every thing from the case up to the gun from the ground up. A .38 or .382 bullet not a .357 or a .40. This way you can make the case take what ever pressure you wish. And the bullet can be pure, made to do just what you want it to do. By the way what do you want it to do...kill deer, people, .....punch thru vest.........or what?
Ok I think the case should be semi-rimmed so when you can start making them you can start in a T/C or even a revolver (what do you think about a bottle neck case? It feeds better in an auto).
Bullets can be made by hand easy enough. It's the case that I have not worked out how to get made.
After that you could start on a firearm.
Is this any help? Or am I not on the right track? Or do you just want to drop it all together?