Vendortron is a protectron that sells weapons and ammo for the Gun Runners. According to the Vendortron, the kiosk was built around it in order to deter theft and assault. As such, the Vendortron and its stock are invulnerable.
If Vendortron sells a gun, it will also have a chance of stocking the appropriate ammunition. If the ammunition appears for purchase, it will be in a large quantity (usually in a stack of 100+ of non-rare ammunition types).
On a terminal inside the Gun Runners factory, it is suggested that the Vendortron's name be changed from Vendortron to an actual name, "like Bob. We're not calling it Bob" which is a reference to the 2000 post-apocalyptic science fiction film Titan A.E.
ps3xbox360pc If you have the Robotics Expert perk, it is possible to disable the vendortron while crouching. It can move around, but will have its head bowed and will appear to slide. It also can't be interacted with. [verified]
ps3xbox360pc Several bugs exist related to vendor inventory replenishment and conditions that prevent caps from transferring from a vendor. See main bugs page for details. [verified]
xbox360pc If you initiate combat and then enter the Gun Runners' complex, it is possible for it to follow you into the building (disregarding the impenetrable kiosk it was housed in). Since it is not treated like a normal non-player character nor ever meant to be fought, it cannot be targeted in V.A.T.S. and has no health. It is therefore invincible (and quite a threat). You can also talk to it while it is hostile. [verified]
xbox360 Sometimes, there is a bug where, if you have been in combat near it, it will act as if you're still in combat, and you will be unable to buy anything from it. Reload a save to fix.
ps3xbox360pc If you buy too many raw materials to create ammunition in one transaction (case boxes, primer boxes, jars etc, but not items such as duct tape or turpentine), the game will crash at the inventory window screen. This can also happen just from simply making a large transaction in general. To avoid this, buy a single unit of raw material (be sure to accept the deal), after buying a single unit, the rest may vanish which may cause more problems. [verified]
Buying all of a single type of item seems to work, and the rest of the items won't vanish.
xbox360 Occasionally, speaking to it will cause it to shrink to about knee length, and after a few minutes returning to normal size. [verified]
ps3 Occasionally after talking to Isaac, then proceeding to barter with Vendortron when Isaac is leaning against the reloading bench, Isaac will clip down through the floor. After traveling and returning to the Gun Runners, he will be inside Vendortron's shack, talking to Vendortron which makes it impossible to barter with it. [verified]
xbox360 When fast traveling to Vendortron's shack you may appear high above the location and may fall to your death, or be severely damaged with broken limbs. [verified]
xbox360 Sometimes, when engaging in combat with the Gun Runner guards or Isaac, Vendortron will attack the player, oddly enough dealing damage toward the player even though it is behind a slab of glass. This can be fixed by reloading a previous save or holstering your weapon. [verified]
xbox360 Punching the kiosk while facing the Vendortron may turn it hostile. If the player then enters the Gun Runners factory it will appear inside the building along with you and will be hostile. After dealing with Gun Runners personnel and leaving, when you return to the Gun Runners Kiosk (after a few days), Vendortron will no longer be hostile, but may appear standing in front of his kiosk rather than inside it. It will still function in the usual way though. [verified]
There is a solution to make the Vendortron friendly again (if you somehow provoke it). Enter the Gun Runner headquarters and type in the command console killall. This will make the Vendortron unconscious. You can either type in resurrect or wait a few moments for it to become conscious again. After this it will revert to its original state.
pc If you trigger combat with it and then go inside the compound and kill everyone it will appear behind you and start to attack you. Even if you fast travel it will follow you, a way to fix this is to fast travel huge distances and wait (if you killed it, you might not be able to buy item from it anymore). [verified]
ps3 If you make it hostile, crouch, and pickpocket it. It will talk to you about the store being closed. Keep trying to pickpocket it, and it will eventually begin to clip through the wall. Carry on, and it will soon be completely out of the shack. It has no health at all, rendering it invincible, and cannot be targeted in V.A.T.S.[verified]
xbox360 On rare occasions, after speaking/trading with Vendortron, then traveling to New Vegas Medical Clinic, Vendortron will spawn nearby walking back to Gun Runners. A Gun Runner Guard may also spawn and walk back as well. [verified]