ok so i really want to work with the gun runners but i cant get into their factory to speak with them... anyone know how to work for the gun runners

you can't work for them but you can pick the lock to their factory.

Umm... You can't. There's simply no quest. And if you set foot in their factory they'll pull the triggers.

shame...

Stealth Boy and Lock pick work great :ninja:

Or do what I do. Take out an Anti-material rifle and kill them all, take their armor and guns, rinse and repeat.

when you do the quests for the Camp McCarran dealer you get to speak to some guy working for the gunrunners. He clearly states that you cannot work for them and won't be able to enter their factory.
BUT - to do the quest for the headLady of the Crimson Caravan you need to get into there - it's actually no problem because the guards in the yard are circling - so you can wait for them to be out of sight, pick the lock and sneak in. There are no guards in the main entry and straight ahead (during nighttime) you get into the workshop where you can steal some stuff and download the info for the CrimsonCaravanLady... As long as you don't enter the guards-sleeping chamber (left as you enter the building) you should be save.
The Sales-Robot doesn't seem to mind you breaking and entering...