Remington Model 760 Carbine in .308Win with 1.5x5 Leupold..
right now it is my model 600 Mohawk in 308
Remington Model 760 Carbine in .308Win with 1.5x5 Leupold.
A 12 gauge shooting 1oz slugs is tough to beat at the ranges you specified.
3. As second, third, etc. shots may be needed, it should be in a lever, pump or semiauto.