"Better for what?" would be my first question. Better for big bear at close range? Better for long distance hunting? Give us an idea of the application or intended use for the gun, and I'm sure several of us will weigh in on the matter.
Given the capabilities of both rounds, I would lean towards the 300 WSM for the following reason: Better choice of bullets with higher BC's. The 325 WSM case holds three more grains than the 300 WSM. For me, that is not enough of a difference to offset the selection of bullets. Compare similar weight bullets for each caliber. You just can't get the BC's in the 325 that you can with the 300. If LR shooting is the goal, my nod goes to the 300 WSM.
I have a 325 WSM. I like it but I only use it for larger game at 300 yards and in. I'm not saying it's not capable of more but that's what I use it for.
Nothing wrong with a 325 wsm, however when I looked into one I found there is noting it will do that the 300 wsm won't do as well if not better. I say that based on available bullet selection for 30 cal vs. 325/8 mm.
