Keeping only one gun would mean we've lost the fight and now it's a matter of survival. My gun needs to shoot fast and be easy to carry (we're on the run). Cartridges need to reload fast and easy without a press, handle homemade blackpowder if necessary, and provide plenty of knock down power up close. Much as I'd hate to leave my long range stuff behind, I'd take my old Marlin 1895 in 44. Rem Mag. It's not very pretty, but it gets the job done.