Rebel Hog. You would go and bring up the 6.5
You are correct about the penetration of that bullet. I quess the 6.5 sort of defy's some of the rules. However I still feel you would get more dramatic kills with the 6.5 using lighter bullets. When the 260 came out, Nosler brought out a 100 grain Partition. I have a couple boxes of them and have not got around to try them. I have used the 120 grain bullets in the 260 and I think the 100 and 120 are the best choice for deer in the 260.
Now I am not saying that the 140 is a poor choice. I just think they have a heavier jacket than needed for thin skinned game. However their performance is beyond question. If I was to have to pick one bullet for the 6.5 it would be the 14o grain Hornady Interlock. For the 260 I would pick a little lighter bullet because lack of expansion has been a little bit of a problem with the 260 and heavier bullets. The 120 Ballistic tip would be an excellent deer bullet for the 260. IME