There are two bags you always need to have at the ready. 1- Your Bug Out Bag and 2 – Your Armed Response Bag. Your Bug Out Bag should contain your survival gear, extra food, water, clothing, first aid kit, etc., while your armed response bag, which can be used seperately or in conjunction with your Bug Out Bag, should contain your ammo including fully loaded rifle and pistol magazines, shotgun shells, fixed blade knife, etc.
My armed response bag is the Voodoo Tactical extended deployment bag in OD green which is a shoulder, sling mounted bag with 4 seperate compartments and is molle compatible. In the front compartment I keep 50 shotgun shells, In the rear compartment I keep 4, Ar-15, 30 round magazines, in 1 side compartment I keep a set of binoculars and spare batteries and in the other side compartment I keep spare ammo pouches and 2, 10 round 45ACP pistol magazines. There is also a front loop for a small flashlight which I keep there for quick access and I have an elite forces fixed blade knife and sheath weaved through the molle attachments for rapid deployment.
rmactsc 
What do you do with your weapons?
Usually my handgun is holstered on my belt. If I’m carrying a shotgun the AR is attached to my bug out bag. If I’m carrying the AR then the shotgun is attached to the bugout bag. Oh and definitely get a quick release single point sling for use on most rifles and shotguns.