Re: 25-06 Rem 115 Berger VLD's
115g NBT at 3200fps has plenty of power to take deer down up to 600 yards, I know that for fact as more then a few whitetails and muleys have bit the dust at that range from my 25-06's over the years. I think I can squeeze 100 more yards out of them in real good conditions. I stopped using my 25-06 on deer a few years back when I started getting into 800-1000 yard shooting/hunting and started using a 300 RUM and 7 RM. However, I am going to start using it once again as an alternative to my 338 EDGE.
Anyways, if you go by the old wives tale of "needing" 1000ft lbs, then the 115g NBT at 3250fps still has that out to 650 yards, and is still traveling almost 2000fps, which is more then enough to make it properly expand and do its job. At 700 yards, you are looking at little over 900ft lbs and 1900fps, which IMO, is still plenty for any deer.
It really is amazing how far standard cartridges with decent bullets will get you. You dont need a magnum to kill deer at 600-700 yards. If your shooting further then that, then yes you need something that is bigger and faster.