Saw them at gunrunners when I was in NV for the first time, didn't buy, didn't have much cash, was low level. Now I'm hitting lvl 25 have 100 Energy Weapons skill, Laser Commander, Weapon Handling, Finesse, Vigilant Recycler, access to Gatling Lasers and all kinds of fancy !@#$%^&* though the Bro's from the Hood. Been back to the Runners at least a dozen times at various intervalls,.. they ain't selling it anymore!

Am I just being extremely unlucky or do such rare items not appear in a vendor's stock after they've allready been there once? Also, could I get it somewhere else? Yeah, Van Graffs', I know, but I tried to impress a certain redhead a long time ago, so they're picked clean.

Much appreciated,

http://fallout.wikia.com/wiki/Fallout:_New_Vegas_weapon_mods#Vendors

i think you can wait right near the robot at gun runners. the merchants restock on sunday and wednesday. time maybe 10:AM. i mean wait which beats going back and forth all the time.

i think at the silver rush, you have to do the waiting outside.

sometimes it take months to get the mods i wanted. sometimes traveling merchants have decent mods. if you see a mod you might be interested in and have the caps, buy it.