Originally Posted by
RonGo
30:06 and 3.08 aren't ballistics twins. 30:06 has about 10% more velocity than the 3:08. The 30:06 also has about twice the bullet selection. The advantage to the 3.08 is a slightly shorter action if you were to buy your guns in a semi automatic. Who really needs a semi in 30 cal anyways. Bullets are the same price. The 3.08 is to the 30:06 what the 30:06 is to the 300 winchester.
The 30:06 does have a much longer neck so if you reload, you have much more flexibility and options for seating depth, etc. I don't like short necks like the 3.08 for reloading if I have the option for a longer neck. The 3.08 is limited to about 180 grains at the top weight but with that it is pretty slow and not a great choice. The 30:06 has a lot more case capacity and neck length to go even up to 220 grain but more realistically 180-190.
Separately, someone mentioned a 0.275 bullet diameter limit and someone else said that allowed a 270. Sorry the actual diameter of a 270 is larger than 0.275.