You people are so impractical, you assume you'll have access to such awesome firearms, and even if you did you assume you'd have enough food and ammo to barricade up and hold out until it all blows over.
No, the single most useful thing you can have during a zombie outbreak is an icecream truck.
You have the mobility to go looking for food/petrol/weapons/medical supplies, to avoid unsafe areas, and to run from the zombies - even the really fast mutant ones - plus you have refrigerative storage to keep all your food and medical supplies sanitary, and a musical siren to be used as a loudspeaker or help beacon so you can communicate with your fellow survivors.
And for added protection, use scrap metal to put spikes and armour on the truck.
What more could you need?
No, the single most useful thing you can have during a zombie outbreak is an icecream truck.
You have the mobility to go looking for food/petrol/weapons/medical supplies, to avoid unsafe areas, and to run from the zombies - even the really fast mutant ones - plus you have refrigerative storage to keep all your food and medical supplies sanitary, and a musical siren to be used as a loudspeaker or help beacon so you can communicate with your fellow survivors.
And for added protection, use scrap metal to put spikes and armour on the truck.
What more could you need?