Re: Long range paper punching and steel ringing.
I've owned Remingtons and Savages and will say Savage for DIY. You can swap barrels/calibers in under 15 minutes with minimum tools.
I'm not a fan of the accutrigger, but it's a start especially if you don't want to purchase aftermarket trigger right away.
Savage factory barrels shoot well, but if you really want to squeeze everything out a Savage...you will want a pre fit Savage barrel. The very best shooting rifle I ever had was with a Shilen select match 26" barrel that I put on my Savage in 308. I'm not a 308 fan, but I had so much invested into 308 reloading components.
If you want efficiency, I'd recommend going with 6.5Creedmoor, 6.5x47Lapua or 260 Remington. I mean a 308 would do fine since you are only talking 600-800 yards, but if you want to go beyond 1,000 yards you will want something in 6.5.
AR10 are nice...I've owned three of them and they shoot nice, but the biggest drawback for me was weight. They are very heavy and I preferred a bolt action. If you do go AR10...I'd suggest 6.5Creedmoor because you can seat the bullets longer compared to an AR10 in 260 Remington.
No matter how much money you throw at a Savage...the action still feels terrible. But if you want an awesome action...look no further than Tikka. You will fall in love with that action, but you will be spending $900 or $1,050 for the Tikka T3 CTR right off the bat.