Fallout: New Vegas ammunition

Ammo boxes
Weight only applies while playing on Hardcore mode.
 * ¹ Compatible with weapons that use 5.56mm rounds.
 * ² Compatible with weapons that use .357 Magnum rounds.

Notable Vendors
These are vendors carrying large amounts of certain ammunition types.
 * .308: Daniel Contreras at Camp McCarran
 * 12.7mm: Daniel Contreras at Camp McCarran
 * 12 gauge shotgun shell: Quartermaster Bardon at Hoover Dam
 * 25mm grenade, .50 MG: Gun Runners (Vendortron and Alexander)
 * 40mm grenade: only available in very small quantities (Gun Runners, Ammunition Vendor at Nellis Air Force Base)
 * Flamer Fuel: Chet at Goodsprings, Johnson Nash at Primm

Loading
To load different types of ammo you are required to go to your pipboy and select the ammo menu. Once there the ammo available for loading will be selectable. (On the PS3 it is not necessary to open the pipboy to load/select different ammo types.)

Bugs

 * Ammo boxes: It seems if a player cannot carry more than 100 surplus small energy cell charges. If the player buys two or more boxes, only one will show up. If the player buys one box, drops that box, picks up the cells, and buys a second box it will have the same effect. Problem may apply to other types of ammo.
 * Ammo boxes: If the item was purchased through a vendor, the player may have to drop the ammo box onto the ground (through the Pip-Boy) and pick it up off the ground to receive the ammunition contained inside the box. *Confirmed* [This has been fixed in the 1.2.0.285 patch (PC)]
 * Occasionally when switching between types of ammunition for a gun, the loaded ammo may become "stuck" and not allow you to switch. To correct this, drop all ammo of the currently loaded type. The gun should then switch to the other ammo type and you can pick the first set of ammo back up. *Confirmed*
 * In reference to the above statement, you cannot change ammo types (by hitting up on the D-Pad), when the weapon is holstered. Additionally you might not be able to change ammo types via pip-boy on an equipped/holstered weapon.  You can unequip in the pip-boy, then change ammo types. *Confirmed, but not sure this is an actual bug.
 * When adding large amounts of ammunition using the console command, the game may crash. This is especially evident when adding .50 MG Incendiary rounds.