Ammunition case

Ammunition cases are containers used to store ammunition, ranging from regular bullets to even missiles. They can also be used to store custom parts and sometimes the weapons themselves.

Usage
In 1964, The Boss, while undergoing a fake defection to the Soviet Union, and more specifically rogue GRU Colonel Volgin, carried two ammunition cases: A square-shaped one containing two Davy Crockett warheads (one of which Volgin immediately used on the Sokolov Design Bureau after stealing the Shagohod), and a rectangular-shaped one containing the Davy Crockett launcher.

During the 1970 San Hieronymo Takeover, Naked Snake, upon escaping from the prison, procured an ammunition container that contained a Mk22 with a suppressor and a Sneaking Suit belonging to the FOX unit.

In 1974, Big Boss and his private military group, the Militaires Sans Frontieres, often procured ammunition cases during their mission in Central America. Likewise, they also recovered some ammunition cases during operations outside Costa Rica and even developed their own ammunition cases.

In 2014, Drebin 893, with his gun laundering business, frequently sold ammunition cases, including at least two custom part containers.

Behind the scenes
Ammo Cases were items used since the first Metal Gear. In the MSX2 games and in Metal Gear Solid, they often had a limit as to what amount of ammo, and what type of ammo, could be restored, although this was largely abandoned by the time of Metal Gear Solid 2: Sons of Liberty, where the limit only extended to whether the player had the weapon matching the ammunition container or not. Likewise, in the MSX2 games, there wasn't much distinction between the ammunition containers outside placable weapons (and in the case of Metal Gear 2: Solid Snake, grenades), which even then did not utilize containers. This was changed in Metal Gear Solid, where all the ammunition, including placable and throwable weapons, as well as the weapons themselves, were given distinct containers. In addition, in Metal Gear Solid 4: Guns of the Patriots and Metal Gear Solid: Peace Walker, the player can pick up spare ammunition containers even when the player's ammunition count is full, with any ammunition being sent to Drebin for Drebin Points and to Mother Base, respectively.