I still love the 300 WM I am fairly confident that the rifle is much better than I am. I just do not shoot it that much and getting used to shooting is accurately takes more practice than I have given it. But a 165 AB going 3175 fps seems like pretty good medicine for a caribou. Based on feedback here, I think the 308 may be less than ideal on the outer ranges of my self imposed shooting range, especially if there is a significant crosswind. I think that I will practice field shooting with the 6.5 PRC, and the 300WM and see if I can get better at shooting with both of them. If I can get good cold bore shots off of a tripod and backpack, maybe I can convince myself to carry rhe WM. Otherwise, I'll be pushing a 142 ABLR with the 6.5
I think that is an excellent idea, regardless of which caliber you choose. Again, I love .308 but the impact velocity drops fast. However, inside of 400 yards, you cannot beat, in the choices you offered, 308 for most affordable and inexpensive and shootable choice. Out to 400 yards, all the calibers are probably within an inch of each other in drop, with 308 having the toughest time with the wind because of its velocity.
Past 400 yards, 6.5 PRC and .300 WM will do better. Recoil really depends on grain weight and desired muzzle velocity. Again, impact velocity, to me, is the deciding factor. My new hot rifle and choice is 7 PRC and while it can suggest that 1800 fps is fine for deer, I still choose 2000 fps because that would also cover mule deer and elk. 7 PRC is still over 2000 fps at 750 yards, which is farther than I am going to shoot at a game animal.
Right now, ranging stuff at work, I know that 300 yards is within an easy comfort zone that probably goes to 400 yards.
On the public hunting land I use, I have ranged sight pictures from 70 yards to 250 yards.
Of these, 6.5 PRC has less recoil by the numbers that .300 WM. It also depends on recoil management. On my 7 PRC, I have a muzzle brake and a cushy recoil pad. So, to me, it feels like a .308 that pushes me back, without feeling punched, about a few inches farther. But outperforms my beloved 308 . And your 6.5 PRC outperforms the 308. Especially for unknown ranges.
I hunt public land and so I use a range finder and some reticle. I also calculate for a few different aiming areas. For example, Saturday of Thanksgiving weekend, I was at a spot where I had good sight at 3 locations in front of me. A creek bed at 50 yards, a mountain cedar tree at 100 yards.
And a line of small trees behind that at 180 yards. Basically, I could hold a hair high or low from the cross-hairs, like an MPBR zero.
And without the recoil of a .300 WM.
To me, and I could be wrong, 6.5 PRC is a great hunting round precisely because of accuracy and impact velocity.