I'm fairly well-versed on the "Rules Of Thumb" concerning what is supposed to work when we try out new bullets or other variables in the ballistic equation. The "bottom line" remains what is shown downrange, though.
The Rules seem a little better at pointing out what DOESN'T work, than at being reliable predictors of good outcomes. Since revolvers and their relationship to Keith SWCs are the germane subject here, I'll add in a bit of personal observation that has largely held true for me since I got rabid about wheelguns and bottom-feeders 40-odd years ago, and about the fodder that gleans the best accuracy.......er, doesn't scatter so randomly downrange.
Here goes--in a revolver, any bullet that is not well-engraved into the forcing cone at the time the bullet base clears the cylinder throat is a lot more likely to Go Poetic downrange than is a longer bullet that achieves that task. After owning or using dozens of 38 Special and 357 Magnum revolvers and likely firing close to 100,000 rounds of both calibers, it has been my experience that no 110 or 125 grain bullet shoots nearly as well as do the 140-200 grain bullets--jacketed or cast. My belief is that the shorter/lighter bullets--mostly jacketed, and mostly some form of RNFP or TC--aren't well-engraved or are differentially engraved by virtue of their bases being unsupported by cylinder throat guidance and stability as the ogive/taper/shoulder takes the rifling.
Germane to J. Miner's texts and the question of full-caliber vs. rebated-diameter front drive bands.......I offer the Lyman #358477. My edition of this mould has a rebated front drive band, and despite the caveats of Mr. Keith and others that such follies threaten to collapse Western Civilization and prompt The End Times, #358477 has shot VERY WELL for many people for many years. #358477 still has two nice fat full-caliber drive bands behind its nose and rebated front band, and its middle band is of a length and placement to have fully engraved into the rifling before its base clears the throat/cylinder face. In essence, the front drive band becomes superfluous as a guidance factor IF the center drive band does its job in the forcing cone. In short, a full-caliber front drive band may or may not make an accuracy difference of its own accord.
