Hows about a lever gun. I'm thinking I'll eventually get a dedicated truck gun. It will certainly be a beater. My thoughts are a good 12 guage pump ( Rem 870 or Mossy 500) under $110, Marlin in some caliber in 30-30/35Rem/357Mag/44Mag, or an SKS. I believe the first to will be the best choice given the fact that if I get pulled over by the police my truck gun won't be quite as threatening and I can easily pass it off as a hunting weapon.