The 165 gr Ballistic Tips you're using now are a great all-around bullet. A few years back I scored on 4 big game animals using that bullet, from a 30-06, but I've also used it happily from a 308 Win.
Black bear at about 325 yards. Quartering away shot. Through the ribcage, destroyed the lungs, bullet jacket recovered in the off-side shoulder but the core exited. Dead bear within 10 yards.
5x5 muley buck at about 140 yards. Was facing me head-on. Put it in his chest, bullet recovered from flank, well expanded after a lot of penetration. Did need a finishing shot when I walked up on it, but that buck wasn't going anywhere.
Pronghorn at about 245 yards. Crossing shot. Don't really need a 30 cal, 165 gr bullet for a pronghorn. Through the shoulder, out the other shoulder. Dead pronghorn in between.
Cow elk at 340 yards, one shot, punched through one shoulder blade, broke the opposite side shoulder blade, may or may not have penetrated the second, never found the bullet or an exit wound. Massive destruction in between. Very quick kill.
It was indeed a great season for me and that 165 gr Nosler Ballistic Tip didn't let me down at all. It's a good bullet but any decent 165/168 gr lead core bullet or a 150 grain mono should do just peachy for you.
Varget is excellent with the 308 Win, and has been for a long time. I wore out a few 308 barrels, and that takes some shooting.
I'll recommend making your choice, stock up on components and do a lot of practice so you can properly place whichever bullet you choose when the time comes.
Best of luck to you this season and into the future!
Regards, Guy