A Ruger 10 22. 22lr ammunition is excellent for zombie killing as it does not make as much noise as other calibers. You can literally carry thousands of rounds and the ballistics is around 90 fps, you only need about 50 fps to penetrate the human skull. Before the ammo scare, it was extremely common and inexpensive, a brick of 500 rounds would cost around $20 to $25. The Ruger 10 22 is a common 22lr rifle, which will make it easy to find spare parts. It is light, durable, and accurate enough for the zombie apocalypse.