Originally Posted by Mikecr
I'll keep looking.
May need a tool(laser mic) & software to derive it...
Wonder how Bryan obtained RT/R
I wouldn't wish my tedious method on anyone.
First step is to mount the bullet in a lathe and indicate the bullet ogive with a dial indicator every 0.025" along it's surface. Then input those coordinates into a computer program that calculates ogive radius and length. Then calculate the radius of a perfectly tangent ogive of that length. Finally, divide the 'perfectly tangent' ogive radius by the measured ogive radius. The result is Rt/R.
I'm sure there are other ways to skin this cat, but I've found this method to be (more or less) reliable and repeatable even if it is a little maddening.