Six, half dozen the other for deer. If choosing the 6.5, I would stay with somewhat lighter cup and core bullet for deer. I took two deer with the 6.5 140 grain accubonds that did not open up much or leave much of a blood trail. Both deer recovered, but it took some tracking. Both double lung shots. Never had any trouble with 6.5 or 7mm cup and core like Hornady Interlock etc.
In the 6.5's ballistic twin 260 Remington we've obtained fine results on deer/pigs with 120 grain Ballistic Tips, 129 grain Interlocks, 125 grain Partitions and some factory loaded 120 grain SST's in Remington Accutip ammunition.
In the 7mm08 it's been all good with 139 & 162 grain Interlocks and 120 grain Sierras.
IMO, both of these cartridges are right in the "plenty of thump, yet easy to shoot" zone for deer cartridges.
