This fully depends on the type of survival situation. Out in the wilderness alone/small group? Your main concern are lightweight and hunting small game - .22 rifle, 12ga, and probably a mid-sized bolt action rifle. In the city in a rioting lawless survival situation? Shotgun again, and you’ll probably want a decent AR and the .357 revolver or .45 1911 as well. Zombie survival? .22 rifle for food and a pair of shotguns for dual-wielding purposes.
Mainly, are you surviving against animals or crazed humans? City or wilderness?
Wilderness Zombies...
and the Equation changes Dramatically!