Many things in Overthrow hold their own storage. It is a list of goods, kept in the campaign save rather than lying loose inside the container.
Ammo boxes, warehouse buildings and most legal wheeled vehicles all have storage. The Storage action shows how many items sit on the list. Opening it shows the list, a cart, and a destination for the cart.
A truck has no storage limit. An ordinary car holds three hundred items. An illegal or armed vehicle holds a hundred items. A helicopter holds the same hundred items, enough for ammunition and not much else. One helicopter, the civilian Mi-8, has no limit at all. Ammo boxes and warehouse buildings hold as much as you put into them.
The cart can go to one of two places. Sending it to this container spawns the goods into its own inventory, ready to pick up by hand. Sending it to any other storage within twenty five metres moves the goods straight onto that storage list, with nothing spawned in between. A warehouse building has no inventory of its own, so it offers only the second option.
Ammunition for a mounted vehicle weapon cannot go into an inventory. It stays on the list instead, and a rearm at the vehicle draws it from there. See Re-arming Vehicles for how a rearm works.
Transfer all to storage turns everything a container carries into list entries in one go, including a truck bed. Attachments and full magazines go on as items of their own. A part-used magazine stays where it is.
An ammo box also carries a Clear inventory action. Officers alone can use it, to throw away whatever a transfer left behind. Rename storage gives a container a name. That name then shows up in the destination list of every other storage nearby.
An ammo box carries two more actions that work on the nearest vehicle. Unload vehicle into storage first turns everything the vehicle carries loose into list entries. It then moves the whole vehicle list into the box. This empties a truck back from the field in one action.
Load storage into vehicle moves only the box list into the vehicle. It leaves the box inventory alone, so a weapon sitting in the box stays there.
A warehouse building carries the same Storage action as anything else. A vehicle parked at one can also reach it from the vehicle menu: Take from warehouse and Put in warehouse. See Real Estate for who may use a given warehouse, and how to buy or rent one.
A warehouse also holds the four bulk construction resources. It uses its own Cargo action, next to the item storage this page describes, and the resource side has no limit either. See Resources for what the resources are and how you move them.
A cargo store works differently from item storage. Goods sit as a quantity, not as separate items. The store measures itself in cubic metres rather than in item count. A truck's resource cargo hold is also separate from the item storage this page covers. A truck can carry both at once.
The Loot action in a vehicle gathers nearby bodies and their loose items. It reaches up to twenty five metres from the vehicle. A jacket, trousers or boots worn by a body stay on it, with the pockets emptied. A vest, backpack or helmet comes off as an item of its own instead. Being watched while you loot makes you wanted, the same as any other illegal act. See Wanted System.