The first revolver I bought was a smith and Wesson 629 with a 6" barrel, I started reloading for it using commercial cast boolits and had leading issues in the first inch-inch and half of the barrel. I have recently bought another 629 with a 4.2" barrel and the leading is much worse in this gun. I have been casting 429421 and 429650's out of ww lead sized to .429. After reading a whole bunch on this site I decided to tackle my leading problem and try and get better accuracy out of these guns. Today I picked up some fishing sinkers to measure my bore diameter, being smiths it made it a little tough to get the measurements, but as best I can get with a micrometer the 6" one measures .429 grove and the cylinder throats are .430 (used a .430 j-word that snuggly fits the throat.) So now I'm going to have to switch to a .431 sizing die for that gun. The shorter barrelled 629 is a whole different beast the cylinder measures .429 and the bore at .430, the sinker I hammered through the barrel wont pass through the throats, so am I safe to assume I need to have the throats reamed out to .431 and size the boolits to .432 for that gun? or would .431 work? Thanks for all your help, I have learned a ton from all you guys.