While waiting for 338-06 Ackley dies a few years back I was able to make up some rounds to fireform for the die maker by neck sizing with 338 WinMag dies using new brass. If memory is right I fired some others about 5 or 6 times using the WinMag dies until they wouldn't chamber easily w-out FL sizing. By then the custom dies were in hand. The 06 & 270 dies wont help you.

You *MAY* be able to use the 358 Win dies in a pinch if there's a tapered expander ball, but you cant FL size with them. If you dont have one, RCBS should be able to supply a tapered expander for your 358 dies. Experiment with some junk 06 brass & see what you can come up with. FWIW Redding dies in 35 Whelen & 358 Win come with tapered expanders, or at least mine did.

These guys may be quicker than waiting for a run from one of the big 3. Good folks... https://www.ch4d.com/ You will need to specify a tapered expander if ordering from CH.

Sacred cows make good burgers when you know what temperature to cook them at.-Rev. Billy