Velocity is only one small part of the equation. Yes the 308nwill drive a 130 grain bullet as fast or faster than the 25-06 will drive a 115. However the Sectional density of those to bullets is not even close. The 130 grain 30 caliber bullet is intended for varmits where the 115 grain 25 caliber bullet has a much higher sd and is intended for deer and other medium size game. The 100 grain 243 is intended for deer. The 100 grain 260 bullet is border lime and can be used for either small deer and big varmits. Deer bullets should have an sd of about 200-250. Less than that will cause lack of penetration and more than that for deer can cause lack of expansion. This if the bullets are of about the same construction.

I have shot quite a few deer with the 243 and the 25-06. I have seen much better performance from 100 grain 25-06 bullets than 100 grain 243 bullets. I sometimes think the sd of the 100mgrain 243 is a bit to high and I would opt for the 85-90 grain bullets. I find the 100 grain 25-06 bullet the best for deer however some prefer the 115-120 grain. I have shot several dozen mulies with the 25-06 and Nosler 100 grain Ballistic tip bullets. I have taken several with the 115 grain BT's as well but really can't see much difference in performance.