When running my games, I generally always story in where a bullet hits someone when one of my players fires their weapon without making a Called Shot. I try to make it plausible. In my friend's game, he has a random hit location table that he uses depending on how much of the character is exposed (cover and which body sections are exposed) and in what type of position he is in (kneeling, standing, prone, etc.) when he gets tagged. It seems a bit complicated for how I like to run things, but it works for him as he's the one who came up with the system and he rarely has to stop to check the tables.

So, my main question is this: In the game that you run (or play), do you (or your GM) have a system for ruling where the bullets hit or is it just left up to the storytelling prowess of the GM?

Subquestion: What are the different rules (house or perhaps something I'm not aware of in canon) on taking massive damage to limbs and whether or not this severs them completely? When do you lose an arm due to a point blank shotgun blast or have your legs shot out from a full-auto stream of lovin' from an Ingram Valiant?

Personally I always story in hit locations, as you do. I just take the damage level taken and narrate the action accordingly. The shotgun got staged down to a light wound? It tore through the armor on the guy's side, but only skimmed the skin. Hold out pistol does a Serious wound? You just shot a guy in the side of the neck! No vital arteries hit, but if he's anything but highly professional he's out of combat. The massive damage thing is probably analogous to wound effects. You can cripple limbs and whatnot, but these are in MM, and are only optional rules. Generally, I just story those out as well, though I occasionally make use of wound effects for fun, the mechanics can get messy.

I've played with limb hit rules that were mostly based on statistics and BS. If a limb was the only body part to be hit, well that was that. If a character standing in the open took a light, then it was considered a graze to the arm or leg, medium might be a clean limb hit or a gut shot, serious was like a chest hit. Not too realistic because damage doesnt increase, which it definitly would in the case of a puntured lung, but normal people don't come with a hit-point meter, more like a "look he's bleeding". These really came into play much because so much lead ended up flying that it usually didn't matter.
as for what point an arm comes off or something, from applied personal experiance, you would have to point blank it with a burst to take it of, but a single shotshell from a few yards would do enough damage to tear the muscle up and imobilize the arm it. And taking an ankle biting stream of lead would likely just break bones, unless your taking hits from a vindicator, in which case what happens to your legs doesn't matter much. of course this comes mostly from growing up on a farm and blasting all manner of things with all manner of ordinance, but it is by no means scientific

Most people who've been around here for a while are familiar with how I feel about hit locations.

That said, were I GMing, there is no way in hell I'd tell my players where they hit. It's very rare in combat to even be sure that you hit at all, let alone knowing where you hit or whether you incapacitated your target, let alone killed him. Giving up that sort of information brainlessly destroys any and all suspense tension, or uncertainty that should define combat, and you might as well be playing a dull videogame.

Whenever I've been asked (as a GM) to do hit locations, I simply rolled 2d6 and used the Battletech tables. Because I've long since memorized them, it's a cheap and simple way to do it. Most of the time, though, we don't really care.

I just crank 'em out on the fly. However, hit locations are actually fairly significant in our games because they can seriously impair a character's ability to perform in one particular area. It doesn't really mix well with canon, because the game isn't designed for a character to have penalties for getting damaged beyond their wound modifier unless the shot was called. We do it anyway just because it adds so much more flavor to combat. Though to be fair, when I GM, I usually stage down the damage a bit if I inflict a particularly nasty side effect.

I remember playing Deadlands in which "staging up your shot" didn't have direct influence on the damage, unless you staged it into a vital area. In that game, you rolled where the hit landed, then based on number of successes, you could move the hit to another (hopefully more vital) location. If that happened, you would do 2 to 3 times more damage... those points being 'gizzards' and 'noggin' IIRC.

Kinda novel for that type of game, probably not so much for Shadowrun.

i tell players where they got hit, but rarely tell players about the opposition. unless the group is just learning, like to let people get used to the rules, and learn to guage what's a killing shot before I leave them in the dark. of course in the case of an SMG burst to the face, well, it's pretty obvious what got hit, and the fate of the sap that got hit

I've been doing the following...

With where you're hit, that's always determined by the story. It's silly to make charts, all things being equal, most hits will be towards the center of mass. If not, it all depends on cover, etc.

However, I've made one change. When someone gets a Serious wound, or Moderate on a called shot, I roll the 'is there serious damage' test from the healing section. If they fail the test, one particular part of them is seriously damaged and no longer 'functional'. I haven't had to bother rolling for which part yet, circumstances usually define that.

I've done this both to account for people who like to make called shots and see specific effects, and because I'm sick of people getting all shot up, then getting magically healed and walking off within five minutes. Sometimes it takes more than Riki Rat Shaman to heal a severed limb.

well, it all is a ballance of detail and gameplay. I played Cyberpunk once. You had to keep track of how much armor you had covering what parts of your body. and each piece of armor could only take so much punishment before it could not protect you. It was a record keeping and gameplay nightmare. One burst of full auto machine gun fire took us 10-15 minutes to resolve. (Each bullet was its own attack)

Personaly I like the idea of dramatic hit locations. It can add to flavor and dosen't get in the way. Maby I can get my GM to use them. Humm. . .

Even with a three-part Damage Code, (Power, Damage Level, Penetration) a hit location table (and of course separate armor ratings to go with that), and automatic fire always divided into 10 or less bursts of no less than 3 rounds each, I don't think it ever took as more than 30-60 seconds to resolve 60 rounds of fully automatic fire -- and most of that was the player being clumsy with the dice. Of course it helps that 2 or more bursts is usually a guaranteed kill in my games.

I can appreciate that even 30 seconds to resolve 3 seconds' worth of autofire from one character can seem like a bit much -- the balance of detail and gameplay is very much a personal issue. I couldn't live with myself ruling that 3 seconds of cyclic fire counted as a single attack.