The survivalist’s rifle should be selected with similar qualifications as the modern military’s service rifle.
In modern forces, this is typically a highly versatile and rugged rifle suitable for use in nearly all theaters and environments. Service rifles are also often selected for their upgradability (e.g. the addition of under-mounted smoke ordinance launchers, sights, flashlights, laser sights, etc.).
The survivalist will need their rifle for a wide number of tasks to include food acquisition and self defense. Unlike a side-arm, a rifle is not typically carried at all times, giving the survivalist a bit more leeway in which models and configurations to choose. Every survivalist should have at least basic rifle marksman abilities.