I am going to go with the scoped rifle crowd. AR's are not truck friendly. The mag sticks out and cuts the interior, the rifle is tall with the PG and Scope and sometimes is difficult to stick out the window and you need some type of tactical sling to carry it around comfortably. We made good war on the maurading dogs up near Telephone, Tx with Remington M-700's and Ruger M-77's. I would look at a good .22-250 or a .243 with 80-85 grain bullets. They both have very light recoil, can shoot far and come in ranch friendly packages. One day we were shooting some big, white, furry, dogs. I had a .223 and my partner had a 250. He dropped his dead and mine took a couple more rounds to help him down the highway to the hereafter. I am not saying the .223 is not lethal, I like it a lot, but the 250 or the .243 just work much better especially on bigger sized dogs. Get a Leupold 1-4 if you want low magnification.
Hope this helps.
Matt