Thanks a bunch for putting it into easier to understand terms. Kinda knew what overbore meant but had a hard time defining which cartridges were overbore. Looks to me it's still somewhat a matter of perspective.
A cartridge is not over bore because it burns more powder. It's over bore capicity when the increse in case size and charge begins to produce diminished returns. It's not an insult or a slur. It's just a clincal term to decribe a condition. Ex: a 308 win with 48gr. powder and 150 gr. slug produces 2800fps. a 30-06 with 53gr. produces 3000fps and increase of 200 fps. the 300 win mag uses 76gr and produces 3200fps. adding 5 grains increased the 06 by 200 fps over the 308. adding 22gr more in the 300 win mag added 200 fps over the 06.
the 300 win mag is over bore capicity