Defining terms

[Steven66]

Just want to make sure I'm getting the words right. "Body diameter" refers to the diameter of the boolit less the diameter of the driving bands? "Bore diameter" is the land-to-land width (assuming that width is an actual diameter)? "Groove diameter" is the groove-to-groove width (again assuming that distance is an actual diameter)? And that, generally speaking, body diameter should equal bore diameter and that driving band diameter should be some ideal number of thousandths of an inch (that is, whatever the gun likes) over bore diameter? Leaving aside for the moment those boolits which don't have driving bands, that is.

[Calamity Jake]

Most rifle boolits have 2 diameters that do the work, the drive band diameter and the nose diameter,
your "body diameter" should be the same as the drive band dia.
"Bore dia." is the bore dia. of the barrel before the grooves are installed, both are round.
"body dia. should be .001-.003 over groove dia. and should fit the throat for good accuracy.

[mdi]

I would think, and I've used "body diameter" as the largest OD of the bullet, the bearing surface. I've always read/heard/figgered cast bullets should have a "body diameter", largest OD, that is .002"+ larger than groove diameter (the larger diameter of a slug pushed through the barrel). Jacketed bullets are normally best when their diameter is the same as the "bore diameter (the smaller diameter of a slug pushed through the barrel). There are cast bullet designs called "bore riding" and they have a section, usually the driving band section that is over groove diameter and a nose section the same diameter as the bore. And that's about the extent of my "expertise" of bullet and barrel diameters...