The forbidden rating makes an item hot property to own... but there's more to it than that.
A forbidden item is something that is highly regulated and will, therefore, be fairly distinctive. For this post, the Ares Alpha is going to be our poster boy.

Strengths of forbidden items:
1) Potency. A weapon with the forbidden rating is almost always going to carry more killing power than its restricted equivalent, as it's either so deadly it's unlicenceable even compared to other weapons in its category, or otherwise it's comparatively effective at getting into areas it's not supposed to be.
2) Intimidation. A runner with an AK-97 strapped over his back isn't saying much about himself. There are street gangers with AK-97s, after all! A runner with an Ares Alpha on the other hand is saying that he has the resources to get one of Ares flagship guns, and is that much more dangerous because of it. Carrying a forbidden weapon is carrying street cred for the violent segment of society, though it cuts both ways... an up and coming ganger with something to prove might take a shot at the Alpha carrier in order to buff up his own rep, while the AK carrier would get by unmolested.
3) Proof of identity. In the shadows a fake identity isn't hard to come by, so how do you prove that you are who you say you are to the street fixer you've never met? a forbidden weapon can do that for you, particularly a heavily customized one.

Flaws of forbidden items:
1) Trackability: a forbidden item as your primary weapon is going to be fairly distinctive. Every Ares Alpha is going to be stamped with so many RFID tags that you'll be hard pressed to get them all. Each Alpha sold is going to be heavily tracked, and if anyone uses one in a crime then it's likely to prompt an investigation into how the weapon got into the hands of a criminal.
2) Distinctiveness: Carry a forbidden weapon and the cameras don't need to catch your face, that gun you carry is signature enough.
3) Repairs: A restricted weapon is fairly easy to get parts for with the proper licence. Forbidden weapons... not so much.

Feel free to add to either list if you see something I've missed or that you disagree with.

No they definedly wont be, that would cause way too many pointless problems for Ares when Alphas turn up en masse in arms of criminals and terrorists.

Carrying highly regulated gear, that usually only military can get its hands on makes for a very convincing argument, that you actually are a military special forces soldier/unit/member.

I have a permit. I have a lot of permits.

"I've seen him pull that knifew while naked!"

Haha!

Thanks for sharing.

That assumes that potency is treated equally and that there is internal consistency among it. We all know that consistency is not a factor in SR4. As an example, look at the HK-227X and the Ingram Smartgun. R class gear yet both contain suppressor which as accessories or modifications are F class gear.

Yeah, or that ATV with a weapon mount that's not restricted whatsoever, but weapon mount itself is a F-class item.
Also, if you look closely, the difference between F- and R-rated assault rifles is the fact that the former have integrated grenade launchers.

From the look of those ATVs, those "Pintle Mounts" are probably just post holes that are typically used more for, "Um, cameras, yeah, cameras, for action scenes shot in the desert!"

Ares HVAR : 11F no underbarrel GL.
Colt M22A3 : 9R rating and has an underbarrel GL.
HK G12A3z : 9F no underbarrel GL.
Nitama Optimum II : 10F no underbarrel GL.
Sernopal vz/88V : 8F no underbarrel GL.
Steyr AUG-CSL : 13F no underbarrel GL.

Also, don't forget the non-mass-produced items that have F ratings, simply because their very existence is illegal. Hacking Programs and Maglock Passkeys are a good example.

Fake licenses/SINs. Milspec armor. Tag erasers.

New challenge: what is the most ridiculous Forbidden item you can find? Ridiculous as in "useless or near-useless item that happens to be forbidden."

Odd, I was sure the M22 had a F rating. Optimum II has an underbarrel shotgun - my mistake. But it only shows how bizarre and inconsistent those ratings are.

FN HAR vs HK G12A3z

FN HAR : 6P/-1AP SA/BF/FA 35© 8R 1,000
Accessories include a laser sight and a gas vent provide 2 recoil.

HK G12A3z : 6P/-1AP SA/BF/FA 32© 9F 1750
Accessories include a laser sight, gas vent providing 2 recoil, and a retractable stock.

So somehow, the HK product is forbidden and costs 750 more and all it gives over the FN HAR is -3 ammo capacity and a bloody stock.

I think it's reasonably safe to say that there is no such thing as consistancy in licensing in-world, thanks to the morass of regulations and treaties and reciprocal agreements.

</conclusion times_reached="3">

(We've been here before, last time it was over bone lacing)

Just like real life.

A fair enough point unfortunately due to the nature of the morass of regulations and treaties these prices would not be consistent in various markets. So we must instead consider that the listed book prices and availability are either

A: Based on the morass of regulations and consequently are representative of a single legal territory.
B: Based on the morass of regulations but are averaged from all legal territories.
C: Not based on the morass of regulations and consequently serve as the natural price of the item.

The problem with A is that it is only indicative of a single legal territory, such as Denver, and is not representative of the pricing in other legal territories.
The problem with B is the unfortunate problem that exists with vehicle and probably other weapons where the listed item is just an example and there are other models with the exact same stats. Protectionist policies would mean that there would be invariable pricing discrepancies between similar models.
The problem with C is that the pricing and availability does not make sense to serve as a base. There too wild of a variance to make this scenario plausible except for the fact that scenarios A and B also do not make sense.

A prime example I can give is the Ruger Mini-14. It's a semi-auto hunting rifle in 5.56mm NATO.

With wooden furniture, it's completely and utterly legal.

With fiberglass furniture and a cooling shroud, it's suddenly a "Military Weapon".

I saw a YouTube video (no camera tricks) of a police officer converting a legal Mini-14 into an illegal Mini-14 in less than two minutes. Note that the action of the weapon is not touched at all, just the shoulder brace, the stock, and the addition of a cooling shroud (A safety device!).

That's okay, you can't legally own a Taurus Judge in California because it's considered a "short-barreled shotgun". In fact, I can make almost any rifle in CA illegal simply by exchanging the stock to one with a pinhole.

In the US, it's the serialized receiver that is regulated and not the whole firearm. However, the information you're talking about is not contained in weapon descriptions.

All in all, it seems like Shadowrun is trying to model a regulatory economic environment but it is so half-assed the half-assery was half-assed.

Or to look at it another way, it has crunch that is functionally fluff because the option is obviously inferior.

or D: "The legality restrictions in this book use the Seattle, UCAS, setting as a baseline." (SR4A, page 313, Jurisdiction, third sentence.)

That would have been option A then, which makes the pricing pretty much inaccurate for any other location and it gives no insight into the cost differences from being in a different jurisdiction. Invariably, some of the cost of R or F items is entirely due to the fact that it is R or F which makes the proper cost of an item impossible to determine.

In Boston, MA, which is more likely to be illegal: any model 9mm handgun, or a super soaker?

Just mentioning the utterly ridiculous.

Come on, you know you can't do that. Next you'll bring up the SR3 flying police drone that was freely available, complete with the included medium machine gun and ammo. The best part was the drone with MMG cost less than the list price of the MMG.

HK. Because you suck. And we hate you.
Posted on October 9, 2007 by correia45

An open letter to the gun community from HK’s marketing department: In a world of compromises, some people put the bullets in the magazine backwards…But it doesn’t matter, because our gun is on the cover of the Rainbow Six video games. Look how cool that SEAL coming out of the water looks… If you buy a $2,000 SOCOM, you will be that cool of an operator too. And chicks will dig you.

At HK, we stuck a piston on an AR15, just like a bunch of other companies have done, dating back to about 1969. However ours is better, because we refuse to sell it to civilians. Because you suck, and we hate you.

Our XM8 is the greatest rifle ever developed. It may melt, and it doesn’t fit any accessories known to man, but that is your fault. If you were a real operator, you would love it. Once again, look at Rainbow Six, that G36 sure is cool isn’t it? Yeah, you know you want one.And by the way, check out our new HK45. We decided that humans don’t need to release the magazine with their thumbs. If you were a really manly teutonic operator, you would be able to reach the controls. Plus we’ve fired 100,000,000 rounds through one with zero malfunctions, and that was while it was buried in a lake of molten lava, on the moon. If you don’t believe us, it is because you aren’t a real operator.

By the way, our cheap, mass-produced, stamped sheet metal guns like the G3 and MP5 are the bestest things ever, and totally worth asinine scalpers prices, but note that cheap, mass-produced, stamped sheet metal guns from other countries are commie garbage. Not that it matters, because you’re civilians, so we won’t sell them to you anyway. Because you suck, and we hate you, but we know you’ll be back. We can beat you down like a trailer park wife, but you’ll come back, you always do.

Buy our stuff.

Sincerely

HK Marketing DepartmentHK. Because you suck. And we hate you.

Not really...

I swear to God I posted something along the lines "because H&K are a bunch of dicks" today, but maybe it's because I'm going crazy.

It's easy, it's Heckler and Koch. Though it sounds better with das German accent.

That post is by the guy who wrote Monster Hunter International. It's from the days back when he was running a gun shop.