Weapons should only be in the bag of an adult. The reason that they are carried is to fend of armed confrontation and problems with wildlife. However it is always best to avoid any armed confrontation whenever possible.
One of the most prudent choices for a gun is a .22 caliber rifle. This is a safe gum and it can help you shoot game such as deer and rabbits in case you and your family end up foraging for food. Firearms of the Remington International brand are also recommended for this purpose. However the .22 rifle has a limited range and stopping power. It also does not afford a clean kill if you are looking to use it to hunt for food.
A cheap and lightweight gun for foraging purposes ions also the 410 GA shotgun which can be silenced with a home-made silencer. The ammunition for this gun is also cheap which means that it is easier to pack many more rounds in your bug out bag. Another good choice would be a center fire rifle chambered for 30.06 or bigger.
You should also have a small chambered handgun in your bag. Make sure it is loaded if you think you are making a trek through violence, war or through an area that is known for its dangerous wildlife. A magnum revolver with a 5.5 to 7.5 barrel might be a good choice.
A semi-auto military type rifle could be considered especially if you are trying to get from an urban area to the country, where facing organized gangs or other threats attempting to block your exit could be a possibility. An AR-15 with collapsible butt stock or folding stocked AK-74 could help get you out of a dangerous situation.
Some survivalist recommend the Ruer tactical 10-22 which can handle most situations and shoot accurately distances over 100 yards.” The specific bug-out gun is the Kel-Tec PMR -30 which has a thirty round clip meaning that if you carry three clips you have ninety rounds of ammunition on you.
Most survivalists also advise against carrying folding stock no matter how convenient. They do not tend to be high quality guns.
It is also important to remember that the gun that works best for you as a tool is probably the one you should care. With the right handler most fire-arms are capable of achieving the desired distances to make a target.