The average whitetail deer hunter shoots his average whitetail deer inside 80 yards. In total, my average is well below that, but the last decade has seen me stretch out, taking more in the 150-170 yard range. Although I've not taken deer with a 260 REM, I've seen them used to good effect. I've currently got a 25-06 that I'm working into my deer rifle rotation, so I have at least a little relevant experience.
Look, if it was simply about performance, you'd have stopped with the 30-06. You switched to 308 WIN, because it was a gift. You're switching to 260 REM now, because. . .?
If you want me to get all shamanic with with you, I'd say the bear still holds sway in your world. Until you go back and kill that bear, every chambering you touch will be inadequate.
Almost none of any of this has anything to do with the physical reality of what happens when a bullet hits a deer. Every centerfire rifle cartridge out there is capable of converting deer to venison, and for every DRT story you read about a rifle, a cartridge, or a bullet there will be another one about a deer that got away. For every 308 WIN maven there is a guy who says it is inadequate and still another that says it over-penetrates.
When I've shot 260 REM, I was impressed by its light recoil. When I saw it used, the owner had drilled a 75 lb doe at 20 yards. This is not an amazing feat. However, most of whitetail deer hunting is like this. You plan for the extremes and you are presented with the mundane.
The other devilishly perverse part of the sport is that you can take the same rifle out, same load, same shot under the same conditions and get completely different results. I'm mostly a heart-n-lungs kind of guy. I have seen every reaction from a deer imaginable -- everything from hit-with-a-hammer to nonchalantly going back to feeding before keeling over. I've tried rifles from a 25-06 to 35 Whelen, shotguns and muzzleloaders as well. Neither 25-06 or 35 Whelen did anything better or worse than a 30-06 or 308 WIN.
For no good reason, I have become enamored with the idea of hunting deer with a light kicking, flat shooting, smaller bullet.
I would agree with you: no good reason. Reason has nothing to do with it. That doesn't mean I disagree with your choice in pursuing a 260 REM. I certainly don't disagree with your quest. Those bears can be tough critters to put down.
OH! One other thing. Whenever I have a misadventure, I always blame the rifle. I always immediately stop using the rifle and go to my backup. The rifle is placed in the back of the safe in a state of disgrace. It is left in the dark for good long time and only put back into service after a severe admonishment. This seems to work. Secondarily, I usually blame the bullet and go about finding a suitable replacement. My remaining inventory of those bullets are usually left to repent their sins for a minimum of 5 years before given the priviledge of returning to service, usually in another rifle.
