Restarting an old GURPS campaign, we're considering a new house rule. This is that if you aim at the "vitals" hit location, which is normally -3 to hit, and if your margin of failure to hit is 1, 2 or 3, then you strike the torso instead.

We're thinking here of ranged combat rather than melee, since we don't know about melee but do know about fire. When firing a firearm, your ability to shoot well is measured by the size of your "group" - you test shooting ability by firing several rounds at a target, and seeing if they consistently hit the same point. So a person whose group (space between two furthest bullet holes on target) is 4 inches is a better shot than someone whose group is 10 inches; they're better at consistently hitting about the same point.

In the military and police forces, people are trained to aim at "centre of mass of target" - for a standing target, a point about where the sternum begins. This is because the torso's the largest part of the body, so even if you "miss" the point you're aiming at, you might still hit some other part of the target. Aim between the eyes and go off-target by four inches, and you miss the them completely; aim at sternum and go off-target by that same four inches, and you still hit them.

Since a person with low skill rating is more likely to have a large margin of failure than a person with high skill rating, and since smaller targets have a larger malus to hit, it seems logical to draw a parallel between margin of failure and "group size."

So with this reasoning, a shot at the "vitals" - which for a firearms shot would be at "centre of mass", since the heart, lungs and spinal column are all close together - which misses by a small amount should hit the torso instead.

Likewise, I suppose, a shot at the eye...?

Thoughts?

That makes sense.

 Matter-of-fact, thats pretty much common sense.

 If someone is untrained (or out of practice /LIKE ME) were to shoot a firearm based just on what they know from wathing movies and TV - then that House Rule of yours is a good working rule.  If your aiming for the torso , you still have a chance of hitting the vitals. The target might move, you might get lucky.

 Reading the above , I just realized that I probably have 17 or 18 House Rules....but I don't think of them as such because GURPS encourages flexibility in the GM. I just figured that was a part of playing GURPS  : going with what makes sense.

- Ed C.

Other way around, mate - if you're aiming at the Vitals, you've a chance to hit the Torso if you miss the Vitals by 3 or less.

As it is, we have JimBob with Pistol-12. He's within 2 yards so no range penalty, and aims at the foe's "vitals". So he's -3 to hit, and will hit on rolling 9 or less. If he rolls 10 or more, his bullet whizzes off into nowhere. Had he been aiming at the torso, which is 0 to hit, a roll of 12 or less would hit.

Aim at torso - roll of 12, 11, 10, etc hits.
Aim at vitals, which are in the middle of the torso - roll of 12, 11, 10 misses, roll of 9 hits.

So if you aim at the bullseye on this target and miss,

then you miss the target completely. Your round lands dead-on, or misses by two feet.

It does stand to reason that if aiming at the torso, you might luckily strike the vitals. However, this effect is fairly easily dealt with by the fact that critical hits lets you do multiples of damage - if the damage multiplied by critical hit takes the guy down to a mortality check, that's mechanically equivalent to a vitals strike multipled for being on vitals which takes the guy down to a mortality check.

I think we're agreeing on this - even if we are failing to use the same words.

- Ed C.