Reality Check: Sniper Shots and Speed/Range Table

[Johnny Angel]

Reading through High Tech, it does address the issues of wind and such for precision aiming. Every +1 requires an IQ based roll at a penalty; additional penalty can be added to these rolls by the GM due to 'adverse conditions.' Any failure requires the sniper to start the process over.


Assuming perfect conditions, perfect equipment, a sniper who has spent the majority of their life doing nothing but learning how to shoot, and a sniper who has either a somewhat high IQ or very good luck (it'll probably be nice to have both), this shot has a good chance of success.

[Kelly Pedersen]

Originally Posted by gilbertocarlos

like i said above, the penalty from wind is in the speed/size penalty(the farther away, more wind matters),

This doesn't make sense. Certainly, the further away you are, the more wind matters. But all things being equal, a strong wind is going to matter more than a light wind, no matter how far away you are. Therefore, there should be a bigger penalty for more wind.
In any case, you're still ignoring things like poor visibility as well. The longest shot on record was made in Afghanistan. Somehow, I doubt that was made in a perfectly dust-free environment. Basic suggests anywhere from -1 to -9 for poor visibility from dust or smoke (Basic p. 548), and suggests penalizing the Precision Aiming roll further for dusty conditions (or windy conditions, for that matter).

Originally Posted by gilbertocarlos

that is why with a x32 sight you don't get range/32 for the penalty of speed/size,

Actually, the reason that a X32 sight doesn't divide range by 32 is because there are more human factors involved than simply the visual resolution of the shot. Small hand movements, for example, will throw off the shot, and the longer the shot, the more those movements matter. Likewise purely random factors that the GM can't account for as task difficulty modifiers, such as the bullet hitting an insect in flight, or something like that.

Originally Posted by gilbertocarlos

and remember of the wounding rules from high tech, 6dx2 pi+ becomes 6d pi+, who becomes average of 31 damage,

True, I forgot the pi+ would up the injury a step. However, that's still assuming an average, unarmored target, which seems unlikely. In fact (according to the Wikipedia page on the sniper who made the shot, anyway), the shot was on an al-Qaeda fighter. We can probably assume at least ST 11 or 12, which Kromm has suggested is closer to "average" for an infantry soldier. The article doesn't mention whether the target was wearing armor, but it's certainly plausible. If he was wearing, say, a TL 8 fragmentation vest (DR 5), the average penetrating damage now drops to 24, which is just barely enough to potentially kill someone with 12 HP.

Originally Posted by gilbertocarlos

if he aims at one specific part of the body, he reduces the skill, but up to 5 points of penalty, he can nulify with precision aiming

Where are you seeing that, exactly? I don't see anywhere in the Precision Aiming description that says you can nullify penalties as well as getting the bonus.

Also, I think you're discounting the probability of failing one of the Precision Aiming rolls. Remember, to claim the full +5 bonus, you have to roll 5 times, against IQ-based Guns-6. Even if we're generous, and give the sniper the same IQ as their DX, and the full penalty bought off, so they're rolling at an effective skill of 15, they still only have an 80% chance of making all the rolls, and if any roll fails, they have to start all over again!

So, really, your chance of hitting (assuming an essentially windless, haze-free day), becomes only about 40%. If we assume enough wind to give -1 to the Precision Aiming rolls, (60% chance to make all the Precision Aiming rolls), it drops to 30% overall. And that's still taking into account only a torso shot, which is hardly a guaranteed kill.

[lexington]

Originally Posted by Kelly Pedersen

This doesn't make sense. Certainly, the further away you are, the more wind matters. But all things being equal, a strong wind is going to matter more than a light wind, no matter how far away you are. Therefore, there should be a bigger penalty for more wind.

Precision Aiming requires a wind gauge so I suspect the effect of wind is largely moot when someone uses PA.

[Kelly Pedersen]

Originally Posted by lexington

Precision Aiming requires a wind gauge so I suspect the effect of wind is largely moot when someone uses PA.

Not according to High-Tech. "The GM may penalize these rolls in adverse conditions (wind, rain, dust, bad terrain, etc.)...", High-Tech p. 84.

[sir_pudding]

Originally Posted by Kelly Pedersen

Not according to High-Tech. "The GM may penalize these rolls in adverse conditions (wind, rain, dust, bad terrain, etc.)...", High-Tech p. 84.

This matches my experience as well. Shooting with a high (or worse variable) cross-wind sucks even if you have wind flags. At that range it's even quite possible for the wind to be blowing in different directions and different speeds along the bullet's trajectory.

[Whitestreak]

In re: the longest recorded range for a confirmed kill:

They were in the Afghan mountains. He had a spotter. He was firing a .50 with hotter than expected loads. The weather was such that they were able to use the passage whirls to aim his shots. IIRC, he used three shots to get that kill.

I've made hits at 1500yds. I could *not* see the target - my spotter worked me in ith four shots. Of course, the target was stationary.

[gilbertocarlos]

Originally Posted by Kelly Pedersen

This doesn't make sense. Certainly, the further away you are, the more wind matters. But all things being equal, a strong wind is going to matter more than a light wind, no matter how far away you are. Therefore, there should be a bigger penalty for more wind.
In any case, you're still ignoring things like poor visibility as well. The longest shot on record was made in Afghanistan. Somehow, I doubt that was made in a perfectly dust-free environment. Basic suggests anywhere from -1 to -9 for poor visibility from dust or smoke (Basic p. 548), and suggests penalizing the Precision Aiming roll further for dusty conditions (or windy conditions, for that matter).



Actually, the reason that a X32 sight doesn't divide range by 32 is because there are more human factors involved than simply the visual resolution of the shot. Small hand movements, for example, will throw off the shot, and the longer the shot, the more those movements matter. Likewise purely random factors that the GM can't account for as task difficulty modifiers, such as the bullet hitting an insect in flight, or something like that.



True, I forgot the pi+ would up the injury a step. However, that's still assuming an average, unarmored target, which seems unlikely. In fact (according to the Wikipedia page on the sniper who made the shot, anyway), the shot was on an al-Qaeda fighter. We can probably assume at least ST 11 or 12, which Kromm has suggested is closer to "average" for an infantry soldier. The article doesn't mention whether the target was wearing armor, but it's certainly plausible. If he was wearing, say, a TL 8 fragmentation vest (DR 5), the average penetrating damage now drops to 24, which is just barely enough to potentially kill someone with 12 HP.



Where are you seeing that, exactly? I don't see anywhere in the Precision Aiming description that says you can nullify penalties as well as getting the bonus.

Also, I think you're discounting the probability of failing one of the Precision Aiming rolls. Remember, to claim the full +5 bonus, you have to roll 5 times, against IQ-based Guns-6. Even if we're generous, and give the sniper the same IQ as their DX, and the full penalty bought off, so they're rolling at an effective skill of 15, they still only have an 80% chance of making all the rolls, and if any roll fails, they have to start all over again!

So, really, your chance of hitting (assuming an essentially windless, haze-free day), becomes only about 40%. If we assume enough wind to give -1 to the Precision Aiming rolls, (60% chance to make all the Precision Aiming rolls), it drops to 30% overall. And that's still taking into account only a torso shot, which is hardly a guaranteed kill.

Well, but there are nowhere what are the penalties from wind, just a citation that need to be one from far away...
I think that even if a DR5 armor protects, it still HT-5 tree times in a row to stop bleeding... or being saved by a doctor
About precision aiming, i was saying that if you need more skill, you can keep using precision aiming, if you have a skill good enough, you don't need to, and most snipers buy the technique, so a guy with skill 15 in Guns(rifle) should have at least skill 12 in precision aiming, even if don't get the +5, he can try again, in about 10m probrably he will get the +5.
And even if is just 30% chance(25% to tell the truth), it is a big chance overall, because it is much more than the record, and have 1/4 chance to break a record, it is a pretty high chance...

[Kelly Pedersen]

Originally Posted by Whitestreak

They were in the Afghan mountains. He had a spotter. He was firing a .50 with hotter than expected loads.

How would these tend to affect the difficulty of the shot? I ask in the spirit of enquiry, since my knowledge of firearms is almost completely academic (I shot a .22 once. I'm a bad, bad farmboy. :-) ).
High-Tech seems to assume that having the spotter doing the calculating is just as easy as doing it yourself, but is that really the case?

Originally Posted by Whitestreak

The weather was such that they were able to use the passage whirls to aim his shots.

What are "passage whirls"?

Originally Posted by Whitestreak

IIRC, he used three shots to get that kill.

So the Wiki article claims, yes.

[SuedodeuS]

Originally Posted by gilbertocarlos

Well, but there are nowhere what are the penalties from wind, just a citation that need to be one from far away...
I think that even if a DR5 armor protects, it still HT-5 tree times in a row to stop bleeding... or being saved by a doctor
About precision aiming, i was saying that if you need more skill, you can keep using precision aiming, if you have a skill good enough, you don't need to, and most snipers buy the technique, so a guy with skill 15 in Guns(rifle) should have at least skill 12 in precision aiming, even if don't get the +5, he can try again, in about 10m probrably he will get the +5.
And even if is just 30% chance(25% to tell the truth), it is a big chance overall, because it is much more than the record, and have 1/4 chance to break a record, it is a pretty high chance...

In order to break a record, you have to be in a situation allowing you to break the record. One big reason no sniper has ever managed to kill someone at longer than 2657 yards is because there haven't been a lot of situations where a sniper has had a chance to do so. There are some other reasons, of course. First off, most scopes aren't made to go out that far, so you end up having to estimate (rather than just using your range adjustments). The sniper in question had to do so - his crosshairs were actually above the target to accommodate bullet drop. This is going to give a penalty to Precision Aiming, as your tech cannot adjust and you have to do it yourself. Another reason is that at that range you can have two or three different winds (I think for the actual shot, there was only one or two, and if two they were going in the same direction). On the sniper show I watched, they tried to recreate the record-setting shot using the same sniper (and spotter, if memory serves). They had three crosswinds - two going in one direction at different speeds, and the third going in the complete opposite direction. They ended up giving up because the spotter couldn't even see where the bullets were impacting to give corrections. Such wind conditions would give a hefty penalty to Precision Aiming.

At a glance, I'd say being beyond the effective range of your scope (that is, the range to which it can be adjusted) gives a -2. A single crosswind is no penalty (unless it's a rather strong wind, although I'd work that as a penalty to the actual shot; see here for some ideas). Each additional crosswind would impose a -1 if blowing in the same direction as the first, -2 if blowing in the opposite direction. Strong crosswinds might impose a further penalty to Precision Aiming.

EDIT: I should note that my knowledge of this shot originates from a History Channel sniper show. As said show was also guilty of stating that sniper rounds actually do more tissue damage from further away (rather, that there's a range window; closer and the round punches through without disrupting itself, farther and it doesn't pack as much punch), the information herein may similarly be suspect. They did interview the actual sniper, however, for what it's worth (it was another sniper that made the "range window" claim).

[Kelly Pedersen]

Originally Posted by gilbertocarlos

Well, but there are nowhere what are the penalties from wind, just a citation that need to be one from far away...

GURPS assumes the GM will apply penalties as appropriate. Basic, p. 345: "If the GM feels that a success roll should be easier or harder in a particular situation, he may assess a difficulty modifier."
And High-Tech specifically calls for a difficulty modifier for wind in such conditions.

Originally Posted by gilbertocarlos

I think that even if a DR5 armor protects, it still HT-5 tree times in a row to stop bleeding...

He has to make one HT roll per minute, starting the minute after he was shot. And anyone can stop the bleeding by making a successful First Aid roll, which is unpenalized and only takes one minute. See Basic, p. 424.

Originally Posted by gilbertocarlos

About precision aiming, i was saying that if you need more skill, you can keep using precision aiming,

No, you are capped at +5. That's the maximum you can ever get from Precision Aiming, no matter what your skill. And you've already accounted for that in your numbers.

Originally Posted by gilbertocarlos

if you have a skill good enough, you don't need to, and most snipers buy the technique, so a guy with skill 15 in Guns(rifle) should have at least skill 12 in precision aiming, even if don't get the +5, he can try again, in about 10m probrably he will get the +5.

If the sniper has a Precision Aiming skill of 12, they have a 22% chance of making all the rolls to get a +5. Each set takes 90 seconds, and, again on average, it takes 3 sets before the sniper is likely to get all +5. So every 4.5 minutes, on a perfectly clear day with no adverse conditions besides range, the sniper can take one shot, which has a 50% chance of missing.
Again, any adverse conditions at all will reduce all these chances significantly. If you assume perfect conditions, your hypothetical skill-15 sniper (still above "professional level"), only hits half the time. I think the record is safe for a while.