I suggest an application process should be devised and made available for people who wish to roleplay as arms dealers, be they roleplaying with factions or not.
This application process should determine a couple of things. where the guns are coming from, who, if anyone, is getting the guns for the player, what the player is planning to do with the weapons, what's the long term goal for the character (kind of breaking the OOC/IC divide here, unfortunately) and the player should be making clear any and all OOC/IC affiliations they have with any factions, all this relatively long application should serve to dissuade and weed out people who would just be going "/me would get the guns from Texas" and merrily skipping off to sell guns to their OOC friends.
The ultimate objective of this application system is to make sure that there is a realistic weapon-to-end-user pipeline.
* The official faction monopoly on firearms is broken, this would made guns resemble more a commodity like any other that is subject to supply and demand, and since more supply would be introduced in the form of these unofficial arms dealers, it would help keep guns at a stable, realistic and attainable price, staving off inflation for a longer time, and diminishing its effects when it inevitably happens.
* More supply of firearms in the hands of smaller dealers means that gangbangers are no longer forced to totally-not-metagame the name of some important Italian or Russian and try to get in good with them - it gives street gangs, stick up crews and other similar factions street-level weapons dealers that they can realistically gel with well enough.
* Factions without OOC connections and copious amounts of money aren't hopeless anymore, since these street level dealers are supposedly far more accessible in terms of where they're situated in the criminal totem-pole.
* Players who are not affiliated with any official criminal factions now have the slim possibility of roleplaying an arms dealer, opening up new avenues of roleplay.
* A handful of official factions are no longer the ultimate arbiters of who gets to engage in criminal roleplay. Let's be real here, without weapons, a TON of avenues of RP are closed off to factions, no robberies, no faction attacks, no self-defence, no gun re-selling. The former system is good, but it places a ridiculous amount of trust and power into the hands of very few people.
* Gives the factions team (?) more avenues through which to control the supply of guns into the server. If whoever deals with this thinks there's too few guns in the server and is already handing out as many weapons as he's comfortable with to all the official factions, then applications can simply be opened and new weapons dealers made. And as always, if there's too many guns, you can always just lower the amount you give out.
However there are some cons as well.
* You risk flooding the server with dirt cheap, disposable weapons, which could lead to an increase in people shooting each other over minor perceived slights, deathmatching, aggression baiting police, etc etc. Nothing new, but always worth thinking about.
* More work for the various teams as the supply of firearms has to be fine-tuned to keep the server well-supplied, but not bursting.
* Whichever team is tasked with dealing with these applications (faction team? mods? testers?) will be opened up to criticism, unwarranted or not, and community scrutiny regarding which applications they're accepting and denying.
* Slightly lowers the prestige of being an official faction.
* More OOC systems in place, more opportunities for meta gaming and favoritism.
In my opinion the pros far, far outweigh the cons.
This also gives the PD the opportunity of minor investigations on individual weapons dealers to take down. Being accepted into this weapon dealer program should come with the stipulation that the PD is given permission to take you down permanently if they manage to build a case against you, encouraging good criminal roleplay and regularly weeding out characters too stupid or short sighted to last long , as well as giving the investigation arms of the police something to do other than build cases against official factions. I could stay here and wax poetic about all the incredible RP opportunities this would bring to both sides but I'm going to leave it here since this is already a really long winded post.