gents, regards woodleighs 460wby/.530 wildcat, original barrels were made 1:14 twist for a 750grain RN.

Wondered if a 535gn roundnose will also stabilise in this twist? anyone with a formula, best guess or sheeps knucklebones feel free to weigh in

Ya, it will stabilize.
You can always go lighter or shorter bullets and be stable.
The biggest problem is going to a Brass or Copper bullet and getting much longer for the same weight.
.530 caliber with a 1 in 14 twist will stabilize a 1.875 inch long bullet.
According to Mountain Molds calculator.

Cheers, John

Ok

So who makes .530 cal barrels and who makes the .530 bullet you are talking about.

Reg S&F

Sprinter for barrels.
Geoff Mcdonald at woodleigh for bullets