Thanks for the answers.
Well guess the 7mm practical will do for the moment.
Going full custom would cost me around 4500$ before i could shoot it(action, barrel, work, reloading dies, brass, bullets). wouldn't have been a problem if i wasn't building another custom rifle this fall... everything is so god damn expensive over here.
Probably aim for a 300nm project the next summer, with some luck i find a used .338 with a custom action before that.