The definition for "overbore" I go by is not uncommon. A cartridge is overbore if you can't find a powder which fills the space below the bullet while giving safe pressures.
In the .22-06 Easling, the ratio of net case capacity to bore area is 5.8 inches. In the .50 BMG it's 5.4 inches. If that version of the .22-06 is overbore, then so is the BMG, yet they've been safely loading the latter for nearly a century. (For a plain .22-06, I'd estimate 6.2".)
Despite the larger relative case size, because the bullet SD used in the .22-06 is much lower, it should be necessary to use a slightly faster powder than the BMG. The powders available to hand loaders today runs through those suitable for heavy bullets in the BMG.
That's why I think the term "overbore" no longer applies. I'm curious why you think it does apply.
Last edited by 2525; 04/24/10. Reason: numbers off
