The characteristics of a 6.5mm bullet will give some counterintuitive results. Remember, it is a long skinny bullet with a high BC.
If a bullet impacts in its design range, the length of the wound channel is practically constant. For Speer and Sierra hunting bullets, that is almost always 2100-2800 FPS at impact. For Hornady, it is more like 1800-2800 FPS. Let me reiterate: Anywhere in that range of impact speeds the bullet will make practically the same length wound channel, about 14". Nosler Partitions do about 2-3" more, have no upper limit, and open at 1800 FPS. Other bullets will have different properties.
With the appropriate bullet, that means you can expect the standard, one-each wound channel at ranges beyond where I would normally choose to shoot. Do the ballistics for your chosen bullet, and make sure you take shots that put the bullet in its design impact range. You may be surprised how far that is for the 260.
I think that fatter, heavier bullets do give you some margin for the times that you hit a major bone. So I might choose a 7x57/162 or 30-06/180 for elk or moose. But would also not hesitate to use a 260/140 if that's what I felt like using that day.
