Reality-testing / Playtesting the Guns Default . . .

[Ulzgoroth]

Originally Posted by vicky_molokh

Hmm. That would provide a free +3 to . . . pretty much all attacks in typical urban engagements, and would drastically change the results of all such encounters in favour of more shots hitting.

Yeah, giving everyone a free +3 at short ranges may be a problem. Though it is an Acc bonus, not a skill bonus, so it only applies to Aimed shots, which are less common in close quarters combat.

I just can't see any way to justify it providing a clear bonus to shots at longer ranges and nothing to shots at closer ranges. If it was structured so that it gradually phased in over distance to make sure adjusted skill monotonically decreased as range increased, something could work in that direction...

[Bruno]

Originally Posted by Eukie

GURPS does all probabilities with a 3d6 distribution, which gives a cumulative distribution of, roughly, the Gaussian Error Function.

Shooting at a circular target in the real world tends to follow more of a Rayleigh Distribution.

Since these two distributions are not the same, it'll be basically impossible to have values in GURPS that correspond to the entire range of real-world values. You might find some sweet spot where GURPS is a simulation of the real world, but GURPS isn't a good model of shooting to begin with, so your results at the gun range are partially just a result of that.

I've spoken to Doug before and I'm sure there were conversations on the forums about making a Twilight-2000-style hit diagram to convert margin of success to how close to your actual target you were. The basic concept is that you've got a diagram of a person, and you've got an overlay with a spiral on it (sorta oval-shaped IIRC? that may vary by weapon) you center your spiral on the person where you were aiming (center of mass, face, left hand, whatever). There's numbers along the spiral corresponding to MOS/MOF, you roll to hit and check the MOS/MOF you got, that's where you actually hit - which may be "not at all" because hands that aren't held near the body are really tricky, or "on the wrong hit location entirely" (shooting center of mass poorly can still clip a thigh or even the face).

[Tomsdad]

Originally Posted by Ulzgoroth

Yeah, giving everyone a free +3 at short ranges may be a problem. Though it is an Acc bonus, not a skill bonus, so it only applies to Aimed shots, which are less common in close quarters combat.

I just can't see any way to justify it providing a clear bonus to shots at longer ranges and nothing to shots at closer ranges. If it was structured so that it gradually phased in over distance to make sure adjusted skill monotonically decreased as range increased, something could work in that direction...

I guess it also going to depend on how much different weapons/projectile will drop as well.

Or put it this way I'm guessing knowing the exact range when shooting at 50 yard target with a bow and arrow is going to give you more benefit than with a high velocity rifle firing a light projectile.


But at this point were talking about different Acc ratings for different weapons ate different range and precise range bonuses applying at different amount at different ranges as well.


A lot of this is abstracted just into different Acc ratings for different weapons and a blanket +1/+3 bonus.

But I guess the reality is a long bow with Acc2 and pistol with Acc2 are accurate in different ways and situations

[Icelander]

Originally Posted by Polydamas

GURPS Fourth Edition Tactical Shooting takes the view that while the first point in Guns skill can come quickly in the right training regime (one which focuses on skills useful in a firefight, not range shooting) skill 12+ is not characteristic of soldiers fresh out of infantry training but of experienced soldiers, serious hunters and target shooters, etc. I tend to follow their take on what is realistic about modern firearms and firearms training, because their credentials are excellent and when they cite a source it always says what they say it says.

In the real world a significant number of people who wear a handgun and completed a training course still have a default or at best a Dabbler perk in Guns (Pistol).

Real people can very easily learn to perform at effective skill 12+ level with firearms at firing ranges, skeet shooting and even hunting. On the other hand, it seems that people in a life-and-death situation, faced with killing fellow humans, actually hit much less than such skill levels would indicate. Tactical Shooting listed skill scores to some extent splits the difference.

The standards for passing a rifle or handgun course in the military or police are often such that even with hefty TDM bonuses for easier conditions than combat, it calls for skill 12 or so in GURPS terms. And it usually only takes a few days to teach recruits to shoot that well at paper. There are shooting tasks that are genuinely difficult, such as long-range marksmanship or the kind of millimeter accuracy that Olympic shooting demands, but shooting at a man-sized target (even a man's head sized one) at ranges of 5-20 yards with a pistol and even up to 100-200 yards with a rifle is not mechanically difficult.

I agree that this is not the same thing as shooting people in combat, but I'd argue that the extensive further training that soldiers receive is not so much about marksmanship as it is about removing Disadvantages and teaching Soldier and Tactics.

If we want to get really complicated about it, we can also say that improving the default on simple tasks like aimed shots at ranges where the trajectory is flat can be done extremely quickly, but learning to judge all the factors that influence long-range shooting and/or improving muscle memory for instinctive point shooting requires much more time.

[Ulzgoroth]

Originally Posted by Tomsdad

I guess it also going to depend on how much different weapons/projectile will drop as well.

Or put it this way I'm guessing knowing the exact range when shooting at 50 yard target with a bow and arrow is going to give you more benefit than with a high velocity rifle firing a light projectile.


But at this point were talking about different Acc ratings for different weapons ate different range and precise range bonuses applying at different amount at different ranges as well.


A lot of this is abstracted just into different Acc ratings for different weapons and a blanket +1/+3 bonus.

But I guess the reality is a long bow with Acc2 and pistol with Acc2 are accurate in different ways and situations

Having different point-blank ranges for different weapons isn't that big a deal.

Actually, what you would do is base it on the projectile speed you already need for the bullet travel rule. Bullet drop is a straightforward function of flight time, at least to an easy approximation. Exactly what number you get depends on how much drop you want to call negligible. 1/10 second (25 yards for pistols, 60 yards for rifles, less for bows) gets you about 5 cm, for instance, while 1/20 second (12 yards for pistols, 30 for rifles) gets you 1.2 cm.

(This range scales with 1/sqrt(gravity), when that becomes relevant.)

[Tomsdad]

Originally Posted by Ulzgoroth

Having different point-blank ranges for different weapons isn't that big a deal.

Actually, what you would do is base it on the projectile speed you already need for the bullet travel rule. Bullet drop is a straightforward function of flight time, at least to an easy approximation. Exactly what number you get depends on how much drop you want to call negligible. 1/10 second (25 yards for pistols, 60 yards for rifles, less for bows) gets you about 5 cm, for instance, while 1/20 second (12 yards for pistols, 30 for rifles) gets you 1.2 cm.

(This range scales with 1/sqrt(gravity), when that becomes relevant.)

Is the drop to speed that linear? (honest question) I mean if it is it's a good solution

[Ulzgoroth]

Originally Posted by Tomsdad

Is the drop to speed that linear? (honest question) I mean if it is it's a good solution

Range/speed gives flight time. Drop due to gravity over the course of that flight time is 1/2*g*t^2.

If you specify a drop distance threshold, that translates to a flight time threshold depending on only local gravity (you need a square root for the calculation, but that's under the hood so long as you stay at 1g), and flight time times speed is range.

So, drop to speed isn't linear, but speed to point-blank range is linear.

I'm not doing anything with aerodynamic effects here (couldn't if I wanted to) but for determining the point-blank range those won't matter.

[DouglasCole]

Originally Posted by Ulzgoroth

Yeah, giving everyone a free +3 at short ranges may be a problem. Though it is an Acc bonus, not a skill bonus, so it only applies to Aimed shots, which are less common in close quarters combat.

I just can't see any way to justify it providing a clear bonus to shots at longer ranges and nothing to shots at closer ranges. If it was structured so that it gradually phased in over distance to make sure adjusted skill monotonically decreased as range increased, something could work in that direction...

Based on this thread, I wrote up some thoughts. I've been in the mood recently for heretical treatments of things, and my post Guns, Guns Sport, and Task Difficulty Modifiers is likely no exception. :-)

[Ulzgoroth]

Originally Posted by DouglasCole

Based on this thread, I wrote up some thoughts. I've been in the mood recently for heretical treatments of things, and my post Guns, Guns Sport, and Task Difficulty Modifiers is likely no exception. :-)

Interesting. Has the implication that shooters who can actually hit the broad side of a barn with Sighted or Unsighted shooting in combat have to be extremely good, though.

Hm. It's an extra complication, but what would you think of pushing the point-blank bonus as a bonus to Sighted shooting, rather than an Acc bonus?

[DouglasCole]

Originally Posted by Ulzgoroth

Interesting. Has the implication that shooters who can actually hit the broad side of a barn with Sighted or Unsighted shooting in combat have to be extremely good, though.

I think this tends to be true, though. Many "street" combats seem to have a 10-25% hit rate where hits are actually scored, and plenty of incidents exist where a dozen or two dozen shots are exchanged with zero hits.

I think the cinematic reality - which includes real-world guys like Delta and some HRTs - where you can just stroll through a fight in a combat crouch drilling each guy in the torso a few times does represent extreme skill.

Hm. It's an extra complication, but what would you think of pushing the point-blank bonus as a bonus to Sighted shooting, rather than an Acc bonus?

I thought about that, and wondered if it was a bridge too far. It seems reasonable. I wonder if you could do something like:

At ranges up to Per yards (or maybe Per-based Guns?), using sighted shooting is more or less point-and-shoot. Your bonus for AoA(Determined) is +4 rather than +1; you may claim the extra +1 for braced if you have two hands on a pistol, or three points of contact with a longarm (such as two hands and a sling).

For shooting at past this range, from Per-based Guns to up to 1/4 the 1/2D range for the weapon, shots taken at hit locations with no more than a -1 penalty may also claim this bonus when using All-Out Attack.


Questions and comments:

1. The use of +4 rather than +1 for sighted shooting out to relatively short distances (4 points in Guns skill is DX-1 or Per-1, for 9 yds with Per-10) would vastly increase the use of AoA(Determined) in my games at distances where it should be used.

2. That distance might not be enough; I was considering increasing that distance based on the Acc of the weapon. To first order, double the weapon's Acc, look up that value on the Size table, and multiply range. Minimum multiple 1. Acc 3 (doubles to 6, look up 5, that's 2) is sight-shooting bonus doubled, so in the example above is 18 yards. So you still have to work it to shoot at 20-25 yds on the range, which matches my experience. Most people start to struggle at 15-25 yds.

For a rifle, say Acc 5, that doubles to 10, which is +4. So you're looking at 36 yds as the place where you are getting AoA(Det) of +4 because you don't ahve to think about bullet movement.

3. I said "torso only" because if I think about an M16 with a carry handle, the offset from sights to barrel is pretty high. With an optic (such as a red dot) on a carry handle, that offset can be 4", which means that for most methods of sighting in, the bullet will travel upwards to the sight line by up to 4", then continue up, starting to descend again in the mid-range (maybe 70-150yds) before crossing the sight-line again several hundred yards (250-350yds, depending on particulars) downrange. So "Point and Shoot" is good for "somewhere on the torso" but not "shot through the heart" without actually knowing the range. So my gut feel would say that if we limit it to "no penalty to hit" situations, we're covering the bases well. If you're intending on taking the time to hit the head or vitals, you need to know where you're about, and know the range, hold-over, and trajectory.