NOTE: the fandom of FNV says and i quote| If a weapon has a GRA counterpart, GRA mods can only be applied to the GRA counterpart and not to the base weapon. obviously there a lot of other places to get these mods. Most of you probably already know that, not all of them, but most of the mods are available from the vendortron just outside the gun runner's factory. This will be a guide on the weapons mods that you can acquire in fallout new vegas and where to find them and/or buy them.