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Old 06-15-2013, 09:10 AM   #1
johndallman
 
Join Date: Oct 2010
Location: Cambridge, UK
Default [HT] [TS] Tactics for realistic suppressors

I think I'm failing to see how to use a suppressor effectively in GURPS gun combat. For example, take the Welrod pistol, (Tactical Shooting p54). It gives -3 to rolls to hear the shot, or -4 if you can press it to the victim's body. You can also get -1 to be heard if you can arrange for all potential witnesses to be well out of the line of fire, but that probably doesn't stack with pressing the gun to the target.

That sounds good, until you look at the table on p158 of High-Tech. The Welrod is a .32ACP pistol, which is a light pistol, heard on an unmodified hearing roll at 256 yards, or with -4 from suppression, on an unmodified hearing roll at 16 yards. But if you're relying on not being heard, giving unmodified hearing rolls is decidedly chancy. If you can put a gun against the target, you can stab him instead, which is a lot quieter: even if he shouts, his range for unmodified hearing rolls (8 years) is shorter than the corresponding roll for the suppressed pistol.

If one goes to the opposite extreme with a suppressed rifle, one can do a bit better. A 7.62 NATO (or 30-06, .303, or 7.62x54mm Russian) rifle has a base hearing range of 512 yards, and a 1/2D of more than that; with a -3 suppressor, one can plausibly hope that people in the general area of the target will fail hearing-3 rolls.

What am I missing? Or are short-ranged suppressed weapons really of dubious value?

EDIT: Yes, background noise, distractions, and so on can make suppressors much more effective. But you seem to need those to stand a decent chance of going unheard.

Last edited by johndallman; 06-15-2013 at 09:27 AM.
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Old 06-15-2013, 09:33 AM   #2
hal
 
Join Date: Aug 2004
Location: Buffalo, New York
Default Re: [HT][TS]Tactics for realistic suppressors

I suspect that there several mitigating factors that need to be examined here. Have you ever noticed just quiet things are in the still of the night? No sounds of traffic? No sounds of dogs (assuming you live with dog owners that shush their dogs excessive barking). Have you ever noticed too, that you don't hear the sounds of children playing? Then take into account that those people who MIGHT hear, also have to make an IQ roll upon hearing it, to know where the shot came from. Next, they have to even know what a suppressed gun sounds like.

Then you have intervening obstacles that can act as sound baffles - vegetation being a good example of this. Then, there are hard surfaces that can redirect the sound such that it can sound louder. Urban environments can be tricky when it comes to gunshots.

So, as far as realistic tactics for sound suppressors? I'd suggest that you may want to assess a -2 penalty to IQ rolls for those who haven't really HEARD gunfire before (Television is NOT sufficient familiarity for that). I'd also consider that some people are behind walls and doors and such, which will add to the range penalties for hearing sounds. Then you have televisions that are on in the homes, or radio's or even people who listen to their IPDDS with their earbuds. Factor in that some people will be on the phone, and others are just plain focused on what they're doing that they might hear a sound but not feel the need to investigate it.

As for the sound suppressor user? The real question isn't whether or not the shot will be heard, but whether it will be acted upon. Someone who has served in the military or is a gun-owner might hear the shot, and recognize it for what it was, but will they recognize the direction it came from? Even if they did recognize where it came from, will they be looking in the right direction by the time the shooter has done what he will and then moves on?

There's a lot of factors that go into the situation, that the GM has to make decisions about and take it from there.
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Old 06-15-2013, 10:02 AM   #3
johndallman
 
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Default Re: [HT][TS]Tactics for realistic suppressors

Quote:
Originally Posted by hal View Post
I'd suggest that you may want to assess a -2 penalty to IQ rolls for those who haven't really HEARD gunfire before.
That one's in High-Tech: -4 for listeners with no points in Guns skills.

For the kind of circumstances I'm expecting to face in a WWII game, such as a small-scale night commando raid, the modifiers are quite unfriendly:

Distractions (B548) -2 or -3 and background noise (-5 for a busy street, -10 for fireworks) might be arranged, but otherwise things will be quiet at night.

Terrain gives +1 (all concrete) to -3 (for heavy vegetation), but I'm unlikely to be able to choose that.

Unfamiliarity with firearms is most unlikely.

Winter clothing over ears: not something subject to arrangement.

Firing through a pillow: obviously doesn't stack with a suppressor, and makes Aim impossible.

Stealth and Knife just looks easier to do quietly, which is making me wonder why the Welrod was developed in the first place. "Watched too many movies" may be the reason.
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Old 06-15-2013, 10:21 AM   #4
RogerBW
 
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Default Re: [HT][TS]Tactics for realistic suppressors

Quote:
Originally Posted by johndallman View Post
Stealth and Knife just looks easier to do quietly, which is making me wonder why the Welrod was developed in the first place. "Watched too many movies" may be the reason.
Perhaps something that GURPS doesn't model: unless you're psychologically prepared to kill (i.e. have done it before), it's much easier to kill someone with a gun than with a knife, perhaps because it doesn't feel to the subconscious like an action that ought to have fatal consequences. (This is why also domestic disputes with guns in the house are much more likely to end up with someone dead than ditto with knives.)

Perhaps see also Fairbairn's comments on the Smatchet: it feels like a scary weapon, so its users become more likely to be confident, determined and aggressive.
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Old 06-15-2013, 11:18 AM   #5
hal
 
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Default Re: [HT][TS]Tactics for realistic suppressors

The fun part of being a GM is trying to describe a scene for the players, and applying the rules from GURPS as best as possible. Using GURPS MYSTERIES (they have modifiers for sound sensing rolls) plus GURPS HIGH TECH, the rules are rather interesting to apply. For instance? Imagine if you will the following:

You have an airport terminal with an airport parking lot in front of it. It has a double wide "road" to permit passengers to exit taxi cabs into the terminal, and for people to pick up passengers leaving the terminal. Then you have a parking lot attendants to accept parking fees from those people who parked in either of the long term or short term parking lots. So picture two football fields side by side for the size of the parking lot, a road with traffic (somewhat light overall, but with people making noise etc, so call it half the modifier of heavy traffic). Then you have an assassin with two assistants acting as extra eyes as he takes out a man who saw too much on his way to leaving the city via plane. The assassin has a 10mm pistol with a silencer that will act as a -3 penalty to anyone who might hear the silenced shot.

WORST case scenario:

Potential witness 5 yards away from assassin as he takes his shot at his victim, but the witness is outside the cone of the shot.

-3 penalty for being outside the cone.
-3 penalty for silencer
-2 penalty for not paying attention to the surprise attack

Now balance this against the following: Gun can be heard out to 512 yards. Each "step" (or halving of the distance) adds +1 to hearing roll. All told, we're looking for a range of 5, which is greater than 4, but less than 8, so the bonus to hear the unsilenced 10mm gun is worth +5. Net -8 plus +5 equals -3 to hearing.

This doesn't even take into account whether or not the listener knows guns or not, and would suffer a further -4 penalty, for a net -7 to hearing. For the average individual with an IQ of 10 and no bonus for acute hearing, the roll becomes a 3 or less on 3d6.

Now, toss in factors like intervening obstacles, and the hearing roll becomes penalized even further. Add distance, and the penalty becomes worse.

Want to have fun? See next post :)
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Old 06-15-2013, 11:35 AM   #6
johndallman
 
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Default Re: [HT][TS]Tactics for realistic suppressors

You're mixing two different systems here. I was doing it with High-Tech.

Doing your scenario with Mysteries, on a quick look, starts with the modifiers you list and then adds +20 for a heavy pistol, then takes off Speed/Range table range modifiers. That gives the witness at 5 yards (-2) about +10 to notice a shot being fired, AFAICS.

I venture to suggest that mixing these systems can give weird results, but either by itself says "this is very noticeable."

Last edited by johndallman; 06-15-2013 at 11:37 AM. Reason: spelling
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Old 06-15-2013, 11:36 AM   #7
hal
 
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Default Re: [HT][TS]Tactics for realistic suppressors

Try to imagine if you will, a broad daylight assassination of some ordinary Joe Smith, a man who perhaps saw something the Mob would rather he not have seen. The contract killer is a reasonably well trained shooter (skill 14) who has access to van, and has successfully followed the victim into a long term parking lot at the airport. The van door opens up unexpectedly, and inside is the assassin with a laser sight device under his silenced 10mm Glock 20.

Range at which an unsilenced Glock 20 can be heard is presumed to be 512 yards (analogous to a .45 caliber gun).

Now further imagine that the target is moving north towards the airport terminal, and is in the open as he walks in the area that cars travel through in order to pull into parking slots. The assassin is firing at him from a van with its panel door open sufficiently wide enough to permit the shot, but not too wide to expose to casual view, the shooter inside. The door is facing East (time is 3PM if that helps) and the range to target is 10 yards.

Attached silencer to the gun is worth a -3 penalty to hearing rolls.

Identify the hearing rolls required by:

Someone inside the airport terminal whose "walls" are thick glass some 40 yards away from the shooter.

Someone inside the airport terminal's entrance way where people are dropped off and picked up via cars and light traffic is passing by.

Someone who is east of the van and some 25 yards away.

Someone who is west of the van some 10 yards away (don't forget, the van's exterior counts as a wall between the shooter inside the van and the outside potential witness)

Assume that everyone is minding their own business (un-alert) or bored (ie security guards at the entrance to the airport terminal who have been on duty for the last 2 hours).

I think you'll be surprised at the total modifiers involved, especially with the penalties for silenced and outside the cone of sound (for an overall -6 just to start).
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Old 06-15-2013, 11:49 AM   #8
hal
 
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Default Re: [HT][TS]Tactics for realistic suppressors

Quote:
Originally Posted by johndallman View Post
You're mixing two different systems here. I was doing it with High-Tech.

Doing your scenario with Mysteries, on a quick look, starts with the modifiers you list and then adds +20 for a heavy pistol, then takes off Speed/Range table range modifiers. That gives the witness at 5 yards (-2) about +10 to notice a shot being fired, AFAICS.

I venture to suggest that mixing these systems can give weird results, but either by itself says "this is very noticeable."
The only things I would take from Mysteries are those things not present in GURPS HIGH TECH, but should be. Hearing sound through a doorway with the door open, is different than hearing sounds from a doorway with the door closed. Hearing sounds through a house wall is different than hearing sounds through a light or relatively hallow door. Hearing sounds through concrete walls is definitely more difficult than hearing it through a frame house.

In reality, shots fired in an urban environment become more difficult because the sounds reverberate off many surfaces, making it nearly impossible to determine where the shot originated via sound alone (although technology is changing that a bit!).

In all? THe High Tech rules are lacking in areas that should have been addressed in that supplement with a little more detail. Lacking that detail, requires that people take a GOOD HARD LOOK at what is present, and see where they differ or agree. For instance, Jungle is deemed to be a -5 penalty to hearing, heavy vegetation being -1 to -3 in GURPS TACTICAL SHOOTING versus -1 due to light vegetation (grass) to -2 medium vegetation (woods) to -5 in heavy vegetation (Jungle). So, while not identical, they are nearly so -1 to -3 versus -1 to -5.
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Old 06-15-2013, 12:02 PM   #9
Fred Brackin
 
Join Date: Aug 2007
Default Re: [HT][TS]Tactics for realistic suppressors

Quote:
Originally Posted by RogerBW View Post

Perhaps see also Fairbairn's comments on the Smatchet: it feels like a scary weapon, so its users become more likely to be confident, determined and aggressive.
I just _had_ to go look for pictures.

http://www.coldsteel.com/Product/97SMATS/Smatchet.aspx

https://www.google.com/search?q=smat...iw=800&bih=475

The data from the Cold Steel blade is a little bigger than the one mentioned in Roger's Wikipedia link. It's practically perfect for a Gurps Long Knife though. 14" blade and a weight of a lb and a half.

Moving away from this interesting digression I can only say that the persons designing and using the Welrod almost certainly didn't have the scientific tools for measuring how close the gun came to being an adequate tool for the mission. Probably the best they could do was to measure how much better it was than the firearms alternatives.

I haven't yet seen any mention of penalties to hearing for being asleep. Waiting until everyone but the sentry is asleep is practically mandatory.

Mostly though you're looking at a trade-off. At least one more Stealth roll to get into knife rather than Gun range and the probably more certain damage of the gun to the head as opposed to the knife to the throat.

If I was GM'ing I'd be looking for a Major Wound to the Neck to equate to a silenced sentry and he still might be able to fight back otherwise in the next round.

Really stopping a man cold with a small blade can be hard. At ST 11 or 12 and a Large Knife you're looking at 1D-1 Imp and a true average of 5 pts when you want 6.

2D-1 to the Skull is a little better. By the RAW even with the P- caliber you're looking at 16 damage after you subtract the (unrealistic) 2 pts for the skull itself. That's "probably fall down and bleed to death" territory if being Harshly Realistic.
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Old 06-15-2013, 12:22 PM   #10
johndallman
 
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Default Re: [HT][TS]Tactics for realistic suppressors

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Originally Posted by Fred Brackin View Post
2D-1 to the Skull is a little better. By the RAW even with the P- caliber you're looking at 16 damage after you subtract the (unrealistic) 2 pts for the skull itself. That's "probably fall down and bleed to death" territory if being Harshly Realistic.
The Welrod is 1d+2; pi- doesn't have any effect on skull hits, so you're basically doing 1dx4, for an average of 14. But shooting the vitals is easier, and avoids skull DR, for an average of 16.5 damage and a minimum of 9.
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