Until he finally retired at age 78, my dad carried an M1 Carbine in his farm truck. He was familiar with it, it fit the space behind the seat exactly, and it took several decades of hard abuse with no lack of function. I shot it not long ago and it still shoots to POI and functions perfectly.
His younger brother still works our farm and has just "upgraded" to a Marlin (881, I think) in .22 Mag for his truck gun. It's all stainless with a synthetic stock, and he swears it's the best truck rifle he's ever had. For knocking over fox and assorted other varmints, it's done very well for him.
When I'm not behind a desk, I take my AR with a varmint upper I built a few years ago. Light, accurate and doesn't mind getting wet or dirty.
Ken Strayhorn
Hillsborough NC