I do realod for my 308 and a friend 338win and got all I need for my other caliber.Well the 308 has good readily available factory ammo. You will get good barrel life as well. That being said if you reload I would favor the 7-08 with some 140ish grain bullets. Just my opinion. Light recoil and flat shooting. Bucks wind well but yet again it’s only 600 yards. Maybe look into a 20” heavy barrel. Shorter barrels tend to be more accurate in my experience. They have less vibration/ barrel whip. I would not mind trying the new 135 grain Berger’s. If building it in 308 Win and only out to 600 yards you could go with some 155 grainish bullets. Hope this helps.
Got a lot of 7mm bullet but more on the 168 and 175gr. Will look to find something around 140gr for my 7mm08.
Got 500 bullet of 155.5gr berger vld and some speer 150 btsp for the 308