I to am shooting a 264 Win Mag. My go to load is W-W Case CCI 250 primer & Nosler 120gr BT with IMR 4350 60.0 gr Max load in Nosler reloading manual. I have used this load on Antelope to 500 yds & complete pass through. I am planning on using it on Mule deer this fall. When at 100 yds it averages under 1 inch. smallest group to date .55 inch. Still working on seating depth & have some Nosler Brass coming in mail from Natches Shooting Supply. I hope it helps with group size since all my Brass prep is just sizing & trim to length. I to have thought about using Hornadys 123 gr A-Max for the B.C. but unsure if it would be relaible on Big Game. My Rifle is Model 70 XTR 24 inch Barrel.
For deer hunting with my remington stainless 264 I have never used anything
but nosler 100 ballistic tips and have never had one deer to take one step DRT every time. I don't shoot for heart lung kill I shoot above the shoulder & below spine they don't go any where with no spine.