Firearms trafficking .. in Las Venturas is a constant eb and flow of (trans)national gunrunners. As much as any other city in the United States there's guns and there's always been a crackdown on the importing of weaponary within this state. San Andreas is a very vulnerable state due to its geography. While easy to quarantine with coastal patrol the system is often exploited by corruption and bribery.
Most firearms derive from within the country. With the United States being the most major gun supplier world-wide the small amount of weaponary that 'disappears' and ends up at the black market is hard to control. Costs reduce as there's no need for illegal import. Like federal and state taxes, bribes are limited to agencies trans-state.
For international criminal organizations it's therefore tempting to set up their operation in cities such as San Fierro, Los Santos and Las Venturas, although the vice of the 'real deal' in San Andreas derives from organized crime groups in Las Venturas, each hoping to keep grasp of a seat in the underworld during their everdecreasing influence after the old ways stopped sufficing.