I never went the .430 re-chambering route. Didn't have to. The Rugers work well with .427 bullets as-is, and the re-lined Win '73 likewise. I looked on it as an ingenious solution to a non-existent problem.
My reference to "rechambering" on the original series (#55-XXXXX) OM Ruger Vaqueros concerned a gun that would not even chamber FACTORY AMMO, at least on SOME of the chambers. This was a manufacturing error. Due to the minimal amount of metal that would have had to be removed, both a noted pistol smith, Clymer Manufacturing (makers of chambering reamers), and Ruger felt there was a high probability of a reamer chattering. Ruger agreed to fix the problem. I can't say for certain, but I'd bet they replaced the cylinder. They did leave the throat diameters at .425"! After experimenting, I determined that using hard-cast commercial bullets (BHN 17-22), of .430" dia., the bullets would (apparently) squeeze down and then, due to residual stresses in the bullet metal matrix, would re-expand after passing through the chamber throats. The gun is capable, by actual test, of firing 1-5/8" five-shot groups at 25 yds...when my eyeballs and hands co-operate
. When SASS went to 2 guns, I was unable to find another .44-40, but obtained a .44 Magnum. I had had the first gun fitted with a .44 Magnum cylinder, interchangeable with the replacement .44-40 cylinder. I was fortunate enough to find a .44-40 cylinder with the looser chambers, but the .425" throats in the chambers, and had that fitted to the 2nd gun, giving me a pair of convertables, which I still shoot (when I have the time to get to matches
) Toward the end of the run of OM .44-40's, Ruger enlarged the throats to .430-.431". But, since mine shoot so well (when I do), I figured if they ain't broke...