I'm in the same boat you are. I have a Dutch Hemburg action and a stock from the defunct Great America Gunstock Co.

I'm considering making mine in 6.5x57R or 303 Brit. Both rounds are easy to get. May also consider the 7x57R. I need to dig out a clip to see if the 6.5x57R fits.

At one time I considered the 444 Marlin.