jraney,
Not a stupid question at all, but a very stupid system. We have no stadardization on how our cartridges are named or designated, which leads to some very bizzare combinations. As others have explained, the '06 here stems from the year of adoption of the modified original .30-'03 cartridge. The military cartridges that preceeded this one, as well as the one before that, both used powder charges as the second set of numbers in their designation' the .30/40 Krag, and the 45-70, using 40 grains of smokeless and 70 grains of black powder, respectively. To compound that even further, the full designation of the earlier cartridge is 45-70-500 or 45-55-405, denoting caliber, powder charge and bullet weight. Today we have the 7-08, in which the "08" refers to the parent cartridge (308 Win) which was necked down to accept a 7mm bullet. On top of that, we have the 250-3000, the original title of the 250 Savage, which incorporated both bore size and velocity with an 87 grain bullet (3000 fps was pretty snazzy back then) into its title. As I said, it's not a stupid question, but a stupid system. There's plenty of other examples I could name here, but you get the drift.
