How do you holster a weapon in fallout new Vegas?

Answer 1

If you mean manipulate an item without putting it in your inventory, you position the cursor on it and hold the 'z' key which is called 'grab'. You can then move your viewpoint around and the item will move as if held.

Answer 2

Press tab to open the PIPboy interface, click on 'weapons' and click on the weapon itself to arm yourself with it. Close the interface and click the left mouse button to draw the weapon. Hold 'R' to holster/sheath it.

While you are in the interface, you can use the numeric keys as weapon hotkeys. Press and hold the key, highlight a weapon, and click it, to set that weapon to the hotkey slot. You can hold any hotkey to view what is assigned to your slots, and you can assign chems and equipment using it too such as the Rebreather. Note that '2' is automatically bound, and changes ammunition types in the current weapon, so if you had a 9mm pistol with regular rounds and AP, 2 will cycle between them.

Answer 3

Press and hold the 'reload' button.