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Ozfer
2013-07-02, 02:37 PM
In the system I am designing, you roll your skill in firearms to see if you beat the difficulty to hit your target at all (Depends on distance, cover etc...), then your target can attempt to duck or whatever. If you hit, you roll the damage according to the firearm + bonuses for an exceptional shot.

The problem I am currently tackling is how to simulate shooting a gun multiple times in one turn. For the sake of this question, lets assume its a pistol.

The character shoots the pistol 3 times in one turn. Should his accuracy be increased? Decreased? Should damage be changed? The one thing that is out of the question is actual multiple attacks per turn (Would take too long).

Beleriphon
2013-07-02, 03:24 PM
The character shoots the pistol 3 times in one turn. Should his accuracy be increased? Decreased? Should damage be changed? The one thing that is out of the question is actual multiple attacks per turn (Would take too long).

I'd do a moderate decrease in accuracy and a bonus to damage. Rapidly popping off shots is going to affect your ability to aim to some degree, but at the same time you have a change to increase your damage.

You could also deal with the attack as a single attack at a penalty, but the target needs to take damage as if hit by three attacks. If you have some manner of resistance mechanic there is the chance any one, or even all, of the rounds do minimal damage.

This would work equally well for weapons that are capable of fully automatic fire.

Scow2
2013-07-02, 03:28 PM
I'd do a moderate decrease in accuracy and a bonus to damage. Rapidly popping off shots is going to affect your ability to aim to some degree, but at the same time you have a change to increase your damage.

You could also deal with the attack as a single attack at a penalty, but the target needs to take damage as if hit by three attacks. If you have some manner of resistance mechanic there is the chance any one, or even all, of the rounds do minimal damage.

This would work equally well for weapons that are capable of fully automatic fire.

But sending more bullets downrange increases the chance of any given bullet hitting. I played in a system where Burst and Autofire increase Accuracy by +10 and +30 on a d% respectively, with "Raises" on the number of hits. Chews through ammo like crazy, though (Such as eating 20 rounds just to land 2 hits on Autofire). It also had alternate effects, depending on what you want to do with "Full Auto", such as hitting multiple targets or merely suppressing an area.

Beleriphon
2013-07-02, 03:41 PM
But sending more bullets downrange increases the chance of any given bullet hitting. I played in a system where Burst and Autofire increase Accuracy by +10 and +30 on a d% respectively, with "Raises" on the number of hits. Chews through ammo like crazy, though (Such as eating 20 rounds just to land 2 hits on Autofire). It also had alternate effects, depending on what you want to do with "Full Auto", such as hitting multiple targets or merely suppressing an area.

While the point of fire multiple rounds to ensure at least one lands, I think from a game perspective it depends on what you're trying to do. Some games do the penalty to attack but increase damage, which is that its harder to get multiple rounds to land but if they do the target is in a bad way. GURPS does it by having you basically make a dozen attacks and resolving them all independently, which works but it is darn slow. Mutants and Masterminds goes with the higher the attack roll (above the target's defense) the more damage you do representing more rounds hitting home.

Gnoman
2013-07-02, 05:17 PM
While the point of fire multiple rounds to ensure at least one lands

That depends heavily on the weapon. While this is the rule for things such as machine guns or assault rifles, where a large part of the point of the weapon is supressive fire and area denial, for close-in combat with pistol, carbine, or submachine gun it is primarily for the increased chance of dropping the target, as burst-fire or a double-tapped pistol will have fairly little divergence in the shot at close range. The goal here is to have an extra chance at the "golden BB" that takes the target out now instead of killing him after he's returned fire and shot you.

Ozfer
2013-07-02, 06:10 PM
It's all very confusing isn't it? It's one of those things that makes perfect sense in real life, but is difficult to model in a game. Thanks for the tips.

Slipperychicken
2013-07-02, 07:43 PM
The problem I am currently tackling is how to simulate shooting a gun multiple times in one turn. For the sake of this question, lets assume its a pistol.

The character shoots the pistol 3 times in one turn. Should his accuracy be increased? Decreased? Should damage be changed? The one thing that is out of the question is actual multiple attacks per turn (Would take too long).

World of Darkness gives a bonus if you use burst fire, but that rapidly eats through ammo and means you could potentially hit unintended targets.

WalkingTarget
2013-07-02, 08:13 PM
The Call of Cthulhu rules have a somewhat complex way to handle it. Each combat "round" happens in two passes.

Combat generally happens in DEX order in each pass.

First pass: anybody with firearms out and ready gets to shoot.

Second pass: hand-to-hand attacks, firearms that needed to be drawn or shouldered first, and people from the first pass whose weapons are rated with at least 2 shots-per-round (if a gun is rated at at least 3 shots per round, then those people who had their weapons ready in pass 1 can shoot again at half of their DEX rank during this pass - note that some weapons can only be fired every other round or even slower due to recoil or just being old single-shot models).

This assumes that each shot is taking the time to make full use of the character's skill. You can use an offhand pistol for extra shots per turn, but they count as "unaimed" which reduces chance to hit (and increases chance of hitting the wrong target) short of having something like laser sights and a high base skill level.

Then there are automatic weapons. Guns with "burst" rating allow you to specify how many rounds you want to fire on a given turn. Each shot fired increased chance to hit by 5% (it's a percentage-based system) up to double your normal rating. On a hit, roll an appropriate numbered-die to determine how many shots hit.

So, let's say you have 50% in the Submachine Gun skill and fire a 10 round burst at somebody with your trusty Thompson (since it's the 1920s) - that would increase your skill to the point where you only miss on a botch (the Thompson is rated to malfunction on a roll of 96 or higher on the roll). Assuming you hit (and the target fails their Dodge check), you would then roll 1d10 to determine how many of your shots hit the target. For each hit, you would then roll 1d10+2 as damage. Considering that the average human character will only have about 12 HP in this system, this is bad news for the target. Burst fire can also be spread among multiple targets, just specifying how many rounds per target and rolling separately for each.

Then again, CoC is an intentionally lethal system where combat is generally what happens when the plans (and the PCs should probably have more than one) fail.

So, in your given example (a pistol) - if it is something small semiautomatic (say a 9mm Glock), you'd get 3 shots per round by default if you had it out and ready, a comparable revolver would get 2 shots, and something massive with lots of recoil only gets 1 (but if you have it out and ready you'd get to fire before anybody going hand-to-hand).

If you had 2 pistols, you could fire both on any turn (for a total of 6 shots for a pair of Glocks), but they'd probably count as "unaimed". If I were running the game I'd probably rule that you could fire two of the bigger, slower handguns accurately in a round, though (one in each pass).

I realize that this is a highly-specific example from a game that might not be at all similar in theme or playstyle to what you're going for, but it's the one whose firearm system I'm most familiar with. I like it because it factors in not just the fact that a drawn gun is faster to use than melee weapons, but also that different guns will have different rates of fire.

TuggyNE
2013-07-02, 08:34 PM
But sending more bullets downrange increases the chance of any given bullet hitting.

This is not the case. Recoil and other factors tend to reduce accuracy, not increase it; the only way you can get better accuracy/shot from firing multiple shots that I know of is to use fully-automatic gunfire long enough to aim the "stream" at the target, hose-style (which is not, I think, the proposal here). Instead, while each individual shot is slightly (or somewhat) less likely to hit, the chances of getting at least one good hit rise substantially, because the target has to be missed by all of the shots to be missed.

For example, if your chance of hitting with one shot is 60%, and you lose -10% in order to fire a short burst of three shots, your chance of getting at least one hit becomes 87.5%, and your chance of getting at least two hits is 37.5%. The CoC rules as explained by WalkingTarget seem to accomplish a somewhat similar outcome with a somewhat different algorithm.

Bulhakov
2013-07-03, 07:59 AM
As a homebrew rule in our WoD games, we used the following approach:

Firearms roll depends on skill and the difficulty on the cover/distance/size of target. The roll determines if bullet hits at all (can be countered by a dodge roll), then the damage is determined purely by bullet caliber and type (plus a bonus if the accuracy roll was extremely successful, minus protection from armor).

- short burst fire (2-3 shots) - you roll each attack separately, but every consecutive attack ups the difficulty of the roll, the damage rolls stay the same (again depend only on ammo type). This seems realistic as overall you get a higher chance to hit.

- full burst fire (15-30 bullets) - roll to hit as for short burst (3 attack rolls, as many damage rolls as landed hits), and multiply the damage (after reductions) by 5.

This homebrew modification made firearms much more deadly, as many tough enemies could be taken down by a full clip of ammo at point blank range.

Scow2
2013-07-03, 10:43 AM
This is not the case. Recoil and other factors tend to reduce accuracy, not increase it; the only way you can get better accuracy/shot from firing multiple shots that I know of is to use fully-automatic gunfire long enough to aim the "stream" at the target, hose-style (which is not, I think, the proposal here). Instead, while each individual shot is slightly (or somewhat) less likely to hit, the chances of getting at least one good hit rise substantially, because the target has to be missed by all of the shots to be missed.

For example, if your chance of hitting with one shot is 60%, and you lose -10% in order to fire a short burst of three shots, your chance of getting at least one hit becomes 87.5%, and your chance of getting at least two hits is 37.5%. The CoC rules as explained by WalkingTarget seem to accomplish a somewhat similar outcome with a somewhat different algorithm.

You said "This is not the case", but then went on to illustrate the point I meant to make (But, in hindsight, I realize I misworded. Should have said Increases the Chance of At Least One Bullet Hitting)

Ozfer
2013-07-03, 11:59 AM
This is not the case. Recoil and other factors tend to reduce accuracy, not increase it; the only way you can get better accuracy/shot from firing multiple shots that I know of is to use fully-automatic gunfire long enough to aim the "stream" at the target, hose-style (which is not, I think, the proposal here). Instead, while each individual shot is slightly (or somewhat) less likely to hit, the chances of getting at least one good hit rise substantially, because the target has to be missed by all of the shots to be missed.

For example, if your chance of hitting with one shot is 60%, and you lose -10% in order to fire a short burst of three shots, your chance of getting at least one hit becomes 87.5%, and your chance of getting at least two hits is 37.5%. The CoC rules as explained by WalkingTarget seem to accomplish a somewhat similar outcome with a somewhat different algorithm.


I'm finding myself liking this explanation of things best. The other explanations were very helpful too, thank you :). Any more theories are still welcome, of course (Still having issues).

Mr. Mask
2013-07-03, 01:09 PM
One thing I'm confused about. You mentioned a dodge roll, and a target number the gun roll has to meet in order to have a chance of hitting. Shouldn't the target number be the target's dodge roll, plus the other factors? Just not sure what to suggest for multiple shots, since I'm not sure what system you're using.

Doug Lampert
2013-07-03, 02:15 PM
In the system I am designing, you roll your skill in firearms to see if you beat the difficulty to hit your target at all (Depends on distance, cover etc...), then your target can attempt to duck or whatever. If you hit, you roll the damage according to the firearm + bonuses for an exceptional shot.

The problem I am currently tackling is how to simulate shooting a gun multiple times in one turn. For the sake of this question, lets assume its a pistol.

The character shoots the pistol 3 times in one turn. Should his accuracy be increased? Decreased? Should damage be changed? The one thing that is out of the question is actual multiple attacks per turn (Would take too long).

Game rule wise, given your basic framework I might go with the chance of at least one hit goes up with increased ROF. So give a modest bonus to hit (say +10% for 2 shots and +15% for 3 shots).

Note the diminishing marginal return, 2 shots is a standard double tap, it has a slight edge.

For every 25% you beat the DC by you get one more hit (up to the number of shots fired), only one bullet can critical hit or get precision damage if you have any such rules, but any confirmation roll or crit chance is based on the chance of at least one hit.

The dodging guy gets a similar bonus for number of bullets hitting (+10% to dodge at least one if hit twice, +15% to dodge at least one if hit three times), and similarly dodges one extra bullet per 25% he beats the dodge DC by.

This maxes out at 3 shots on the basis that if someone is firing a pistol or similar non-automatic weapon more than 3 times in a round (and has time to bring the gun back in line for the fourth shot rather than it being totally wild), then you need a shorter round, and full automatic is different enough to need different rules.

fusilier
2013-07-03, 02:40 PM
The problem is the recoil of the weapon throws your aim off -- so after the first shot your chances of hitting decrease. GURPS handles this by rolling for each shot independently, and having a "recoil modifier" that is applied cumulatively to the subsequent shots. You have more "chances" to hit (because you get to roll for each shot), but the individual chance that each shot hits drops.

GURPS handles fully automatic weapons differently: with bursts. In this case the "burst", of up to four rounds, counts as one "shot", i.e. one roll, and the recoil penalty is applied to subsequent bursts. A chart is used to determine how many shots from the burst hit (the better the roll, the more shots hit); only if all 4 shots are fired does a miss by one still give one hit. In dodging, the target gets to dodge the entire burst, rather than rolling for each shot.

It should be noted that GURPS uses one second rounds, while firing three shots in a second is certainly feasible with an automatic pistol, you have precious little time to adjust your aim between shots. If you are using longer rounds, then the recoil penalty might be dispensed with.

Mike_G
2013-07-03, 03:19 PM
I'd allow additional attacks at a cumulative penalty. Each hit does damage. This would only work for weapons that could be fired rapidly. Some limit on total rounds should be set, depending on the weapon. The penalty could be greater for weapons with more recoil (easy to double tap with a .22, with a .44 Magnum, not so much.)

So, pumping multiple shots downrange means it's more likely some of them hit, each additional shot would be less and less likely to hit, until you stop and re-acquire your sight picture, which is pretty realistic.

This cuts down on math, speeds play, and doesn't make "spray and pray" an auto hit, because it just plain isn't.

There was a test a sniper team did in Vietnam when tasked with improving the shooting of some regular infantry. They took a regular infantry platoon and had one guy fire semi auto, prone, slow fire and the whole rest of the platoon fire standing up, full auto and count the hits. The single rifleman who actually aimed got more hits than his thirty or so buddies spraying and hoping.

So, if one aimed shot has a 10% chance to hit, that doesn't mean that ten quick shots is a guarantee.

Auto fire is good for when you can't see the target anyway, like at night or heavy brush when you just want to make an area more dangerous for the enemy to be in, or force him to keep his head down so you buddies can outflank him. If you can see the target, take that split second to aim and squeeze, then re-acquire, aim and squeeze.

genmoose
2013-07-03, 09:48 PM
Here's a few points I would like to throw out:

1. Subsequent shots do not make the first shot less accurate. If you have a three round burst, shot 1 will go off as accurately as firing semi-auto. Shot 2 and 3 will have significantly less accuracy.

2. A bullet hit causes the same damage regardless if it is shot 1 or shot 5.

3. Ammo capacity is a significant variable in how fast you fire a weapon.

4. The probability of 'ducking' or otherwise actively avoiding a bullet once it's fired is almost nil (Mythbusters did an episode on this). However subsequent shots might be dodged.

Here's a potential mechanic to use.

Have the player decide how many rounds to fire. The 'to hit' portion is decided by your firearms skill (as you stated) plus a die roll, plus an accuracy rating for the weapon plus a recoil factor for each subsequent shot (unique per weapon). If the player 'hits' then you determine the number of shots that landed on a sliding curve. Each hit is worth some amount of damage.

So let's try to play through an example and see if it could work.

Shepard, the PC, is trying to shoot the big bad guy who's behind some cover. He's one of those guys that has far too many guns and has a few to choose from:

Smith and Wesson Model 29 (8.5" barrel)
Accuracy rating: 10 (longer barrel)
Recoil rating: 3/2/1/1/1 (maximum rounds fired in one round)
Overshot: 5
Damage: 2d6
Magazine: 6
Ammo: .44 Magnum

Smith and Wesson Model 29 (4" barrel)
Accuracy rating: 5 (shorter barrel)
Recoil rating: 4/3/2/1/1
Overshot: 5
Damage: 2d6
Magazine: 6
Ammo: .44 Magnum

FN FiveSeven
Accuracy rating: 8
Recoil rating: 4/3/3/2/2/2/1/1/1/1/1/1/1
Overshot: 4
Damage: 1d8 (ignores first 4 points of body armor damage reduction)
Magazine: 20
Ammo: 5.7x28mm


Ok let’s do some math. Shepard has a firearms skill of 18, and the big bad guy is behind decent cover that gives him an effective AC of 45.

Case 1: Shepard uses his long barreled Model 29 and chooses to fire two shots.
To hit = 18 (Shepard’s skill) + 10 (weapon accuracy) +3 (follow on shot) + d20 (roll) = 1d20+31 against an AC of 45. He needs to roll a 14 or better which is about a 35% chance of hitting.

If he were to fire another shot, that would add 2 to his attack bonus, which would increase his chance to hit to 45%.

Now to figure out how many bullets hit. The first hit is given. To figure out the probability of the follow on shots we could go through some sort of curving table or work probabilities for each shot but that sounds like a lot of work. Plus it doesn’t take into account the difficulty of the shot.

Since you seem to want to keep the pace moving, why not use ‘overshot’ to determine how many other hits land.

If we go back to our example, let’s say Shepard fires three shots and rolls a 17. His attack is 17 (roll)+18(skill)+10(weapon accuracy)+3(second shot)+2(third shot) = 50.
His target had an AC of 45 so that would be a hit. He then beat his target’s AC by 5 points. So that would allow one ‘overshot’ with that weapon. Therefore out of the three shots fired, two landed. Damage would be 2x2d6.

If he had the same roll and only fired two shots his attack would be 17 (roll)+18(skill)+10(weapon accuracy)+3(second shot) = 48. He would still hit the target but only land one shot for 2d6 damage.

Case 2: Shepard uses his FN FiveSeven and fires 10 rounds at the target (spray and pray). His attack would be 17 (roll) + 18 (skill) + 8 (weapon accuracy)+4+3+3+2+2+2+1+1+1(follow on shots)=62 So he’s beaten the AC and did so by 17 points. The overshot on this weapon is 4 so (17/4) means he hit the target 4 times. Damage would be 4x1d8.

There are lots of things to tweak here depending on how crunchy your players want to get. I would personally like it because as a player I could tailor my weapon to my play style. If I want slow and steady aim, maybe I go with a long barrel, but if I want to spray more I can use a more maneuverable short barrel. To me it offers a lot more fun than the normal ‘I choose a long sword that is just like everyone else’s long sword unless it’s magic’.

The next big variable to take into account is reloading. So the above math will always benefit more rounds fired so there has to be a drawback. You could setup standard reload times for various weapon classes. If we work of d20 lingo reloading a revolver could take a full action (cannot fire the entire next round), and maybe a magazine weapon would take a partial action (can only fire one shot the next round). Anything with a belt (M249 for example) might take two or three full rounds.

For example: Shepard gets some horrible rolls and blows through his entire 6 shots on the Model 29. He can be ballsy and reload in the open, hoping his opponent misses, but be ready to fire the next round. Or he can duck into cover (1 round), reload (1 more round) and then be ready to fire. If he used the pistol with a magazine, he could take cover and reload in one round and fire by round two.

This also works against a spray and pray attitude. If Shepard takes dead aim and fires one shot per round with his Model 29, he has a 20% chance of hitting each round. But he can fire for 6 rounds straight before reloading. If he fires three shots per round, his probability to hit goes up to 45%, but he can only do that twice, before he has to sit out another round or two reloading. Add a maximum ammo capacity and there’s the chance Shepard could run dry before the fight’s over.

Depending on how in depth you want to get this could add a lot of roleplaying to a group game. Mix in a slow and steady shooter with a sprayer and you help cover the weaknesses of each approach. Also, larger magazines would obviously be valuable but they are probably more expensive. And taking a page from today’s headlines they might also be illegal. An illegal 30 round magazine would kind of be like using a poisoned dagger in old school D&D.

You could also add perks/feats to reduce reload time or maybe double the weapon accuracy if the shooter takes deliberate aim and only fires once per round.

Is this system perfect? Absolutely not. We’re not taking into affect suppressive fire, or how return fire would affect accuracy. You may be able to work out some details on snap shooting or being able to take time to line up a shot but that depends on how much math you want to do and what level of detail your players demand.

Anyway, I had fun running through this idea tonight and hopefully it will be helpful for you or someone else reading this.

Ozfer
2013-07-03, 10:29 PM
Mega-Snip

I am way too tired to read that now, but seriously- Thank you! You apparently put more though into this than I did. This is the most impressive thread reply I've seen yet.

EDIT- Shouldn't have full quoted.

The Dark Fiddler
2013-07-04, 07:32 AM
One thing I'm confused about. You mentioned a dodge roll, and a target number the gun roll has to meet in order to have a chance of hitting. Shouldn't the target number be the target's dodge roll, plus the other factors? Just not sure what to suggest for multiple shots, since I'm not sure what system you're using.

That's only if you're doing it the way D&D does it. Here's the way Dark Heresy does it, which might help OP come up with a way to model the gunshots in his system:

Everybody has a Ballistic Skill stat. In DH, stats are measured from 1 to 100 (though I suppose it's possible to go outside that range, theoretically) and you make Tests by rolling a d100 (or d% if you prefer), with success happening if you roll under your stat.

When you want to shoot somebody, you make a Ballistic Skill test. If your BS test succeeds, then you've aimed accurately; the target, if they have a reaction left for the round (typically you get one a round), can attempt to dodge. This is done by them making a Dodge test (which is their Agility stat plus any bonuses they have specifically to the Dodge skill), and if they succeed then they dodge.

Now, when you go for automatic or scatter weapons (like shotguns) it works a bit different. Automatic bursts give you a bonus to your accuracy (+10% or +20% I think?), and then you make your BS test normally. If you succeed, you still hit; if you succeed by a certain margin, however, you land an extra bullet. For a scatter weapon, for example, you land an extra bullet for every 20 points you beat your test by; if you had a skill of 56 and rolled a 32, you'd have beat your skill by 24 and would therefore get an extra bullet. Similarly, if they Dodge spectacularly well, they can dodge these extra bullets.

The_Tentacle
2013-07-04, 09:48 AM
You might also want to add something for aiming at a target who hasn't moved since the last time you shot him; you'd get to adjust your aim based on what happened last time. Perhaps just over multiple rounds, or maybe if you're taking just two shots in a round or something.

Mr. Mask
2013-07-04, 11:04 AM
Fiddler: I feel I lack proper understanding of the system, since that sounds inefficient to me. My personal inclination is that you should combine the two rolls into one, and calculate how many bullets hit if any. That, or roll for each potential hit against their dodge.

Mostly, it's because I dislike the idea of comparing margins of success to find out how many shots hit (not saying anything bad about the system--I don't know it, and these are only my view of it from that brief description).

The Dark Fiddler
2013-07-04, 12:53 PM
Fiddler: I feel I lack proper understanding of the system, since that sounds inefficient to me. My personal inclination is that you should combine the two rolls into one, and calculate how many bullets hit if any. That, or roll for each potential hit against their dodge.

Mostly, it's because I dislike the idea of comparing margins of success to find out how many shots hit (not saying anything bad about the system--I don't know it, and these are only my view of it from that brief description).

The thing is, though, if you just combine it into one roll then you're cutting out the mechanic of dodging, essentially. Since you only get one reaction a round (typically, that is), it's an important choice what attack you decide to dodge if you're up against enough attacks that it matters.

Slipperychicken
2013-07-04, 01:01 PM
The thing is, though, if you just combine it into one roll then you're cutting out the mechanic of dodging, essentially. Since you only get one reaction a round (typically, that is), it's an important choice what attack you decide to dodge if you're up against enough attacks that it matters.

If you want to have dodging and only one roll, wouldn't it make sense to just have dodging subtract from the shooter's chance to hit? Perhaps it would be phrased as "you must exceed your chance to hit by the opponent's dodge modifier"? Then the player rolls and announces the value by which he exceeded his hit chance, and the DM declares it a hit or miss.

Scow2
2013-07-04, 01:31 PM
If you want to have dodging and only one roll, wouldn't it make sense to just have dodging subtract from the shooter's chance to hit? Perhaps it would be phrased as "you must exceed your chance to hit by the opponent's dodge modifier"? Then the player rolls and announces the value by which he exceeded his hit chance, and the DM declares it a hit or miss.

No, it doesn't work that way, because that breaks the math.

Mike_G
2013-07-04, 04:20 PM
I think the best way to simulate multiple rounds is the way D&D 3e does iterative attacks. If you fire four shots, roll four times, increase the penalty each time. You can't dodge a bullet, but you can dodge and move around, making it harder to aim, so just allow the target a defense modifier to any attacks he's aware of if he chooses to evade, serpentine and dive for cover. Of course, that would make his own shooting have a penalty as well.

Trying to simulate emptying the clip with one roll is always going to be messy.

holywhippet
2013-07-04, 08:00 PM
Of course, your players could come up with a justification as to why they shouldn't suffer recoil penalties: http://en.wikipedia.org/wiki/Heckler_%26_Koch_G11

Basically the G11's internal parts are "floating" so when a bullet is fired they just slide back against a spring. This works for the first 3 shots out of any burst - after that the mechanisms have been fully pushed back and the recoil will be felt directly.

Anyway, I'd make the characters make a roll against recoil for each shot based on some combination of strength and skill, possibly modified by the caliber of the bullet they are firing. With each shot they make the roll and come up with a penalty (if any) for the next bullet. Either make this modifier cumulative or possibly have it able to be cancelled out by later bullets (ie. the shooter has wrestled the gun back into position).

It is hard to do realistically though since most bullets being fired in a real fire fight from automatic weapons are intended to suppress the enemy.

Ozfer
2013-07-05, 05:49 AM
I am using a D6 success system. Ranged attacks must first beat distance, cover, target movement, etc... And then, the target can dodge. Thanks for more replies, I'll read them in a little bit.

Autolykos
2013-07-05, 08:53 AM
For semi-auto, I'd resolve the attacks individually and add a fixed recoil after each shot. For bursts, I'd do one roll for all shots. Success means one hit, and you can get as many additional hits as the margin by which you passed the check, divided by recoil (but no more than you've fired). Recoil compensation allows you to ignore a fixed amount of recoil each round.
This covers pretty much everything you can do with small arms. A heavy machine gun on a fixed mount is a whole different thing, especially when mixing some tracer ammo in the belt. You can pretty much ignore recoil after a certain point and "walk" your fire on the target. If you do that, you'd get a small fixed penalty and roll again for every round as long as you fire full auto - but your result can't be worse than what you rolled last round, unless you switch your target.
EDIT: You can also allow to "aim carefully", which will give a significant bonus to the first shot fired in the next round. Everything thereafter is basically spray&pray.

Ozfer
2013-07-05, 12:56 PM
For semi-auto, I'd resolve the attacks individually and add a fixed recoil after each shot. For bursts, I'd do one roll for all shots. Success means one hit, and you can get as many additional hits as the margin by which you passed the check, divided by recoil (but no more than you've fired). Recoil compensation allows you to ignore a fixed amount of recoil each round.
This covers pretty much everything you can do with small arms. A heavy machine gun on a fixed mount is a whole different thing, especially when mixing some tracer ammo in the belt. You can pretty much ignore recoil after a certain point and "walk" your fire on the target. If you do that, you'd get a small fixed penalty and roll again for every round as long as you fire full auto - but your result can't be worse than what you rolled last round, unless you switch your target.
EDIT: You can also allow to "aim carefully", which will give a significant bonus to the first shot fired in the next round. Everything thereafter is basically spray&pray.

Now this, I like. It never ceases to amaze me how friendly and helpful Playgrounders are. Thank you autolykos :). I actually already had the aim carefully option. The way you laid out your suggestion meshes with my system perfectly. Do you mind if I steal around 75% to 100% it?

Autolykos
2013-07-05, 03:42 PM
Sure, take whatever you like. If it results in another good system, it was worth it :)

Ozfer
2013-07-05, 04:42 PM
Well, I'm optimistic on the system, but who knows, maybe it's terrible. Either way, thank you so much, and I will be sending you a copy if I ever have a finished product (Again:Optimistic, not definite ;P).

tasw
2013-07-05, 04:49 PM
In the system I am designing, you roll your skill in firearms to see if you beat the difficulty to hit your target at all (Depends on distance, cover etc...), then your target can attempt to duck or whatever. If you hit, you roll the damage according to the firearm + bonuses for an exceptional shot.

The problem I am currently tackling is how to simulate shooting a gun multiple times in one turn. For the sake of this question, lets assume its a pistol.

The character shoots the pistol 3 times in one turn. Should his accuracy be increased? Decreased? Should damage be changed? The one thing that is out of the question is actual multiple attacks per turn (Would take too long).

This is a problem of time scale. i spent a few years deployed in active zones in the army and i used to laugh at how you could only shot once per 6 seconds in D20 modern, and less if you bothered to aim.

Modern weapons fire very quickly and a halfway trained user can re-acquire a target after recoil very quickly.

What I would do is what I did before. You make each round in a modern combat system 2 seconds and adjust movement accordingly. And allow a shooter to substitute a move action for an attack action. That way you can aim and shoot once per round or shoot twice without aiming. Which is accurate

Ozfer
2013-07-06, 01:02 PM
That's actually the scale I am already using, more or less. One round is assumed to be 1 to 3 seconds.

AttilaTheGeek
2013-07-07, 10:42 AM
Taking into account all of the ideas that have been proposed thus far, what about this:


You can fire any number of shots in a round, up to the maximum allowed by your weapon.
Make one attack roll.
The attack roll takes a penalty (roughly -1 on a d20 or -5% on a d%) equal to the number of shots fired after the first. For example, if you fired four times and were using a d20, you'd take -3 on your attack roll.
For each [1 on a d20 / 5 on d%] by which you beat the target's [AC/defense/dodge roll], you hit with one additional bullet, up to a maximum of the number of bullets you fired.


This system means it's optimal to fire single shots to hit someone who's very difficult to hit, but if you know you're going to hit you can let loose with full auto.

Mike_G
2013-07-07, 12:49 PM
That doesn't really reflect reality. People generally fire multiple shots in the hope that at least one hits, so firing three rounds at a difficult target makes sense. That's why we have a "burst" setting on the M16.

Don't try to make it one roll. Roll for the first shot as normal, and each additional shot at a cumulative penalty. Big, high recoil weapons will have a bigger penalty.

That way, a single shot has the best chance to hit, but if you have a lousy chance, three shots at lousy -1, -2 and -3 have a better chance of putting some metal on the target.

lesser_minion
2013-07-07, 05:03 PM
Everything I know about this topic probably became obsolete before I was born, but I'm bored, so...

As I understand it:

Firing more than one round in quick succession with a handgun -- a "double tap" -- is intended to increase the amount of injury caused. The theory here is that you train yourself so that once you've recovered from the recoil, your gun is pointed exactly where it was before.
Aimed shots are usually considered more effective than full auto. For most weapons, fully-automatic fire is a "holy flaming rancid pineapples from hell!" measure (totally authentic military vernacular, of course) that's used when an enemy is extremely close and there's no time to aim.
Most rifle-calibre man-portable weapons are extremely hard to control on full auto -- both the M16 and FN FAL have had their full auto capabilities removed (by at least some users) on the grounds that it proved more of a threat to low-flying aircraft than to enemy soldiers.
Sustained-fire machine guns are a thing. It's not uncommon for them to be used with a bunch of maths in order to fire at a particular location rather than at an enemy that the crew can see.
As a rule of thumb, an SMG or assault rifle is assumed to have enough ammunition for five short bursts. Keeping an accurate count of how many bullets have been used is basically impossible, especially in a real fight.

Whether or not this information is really worth using in an actual game (as opposed to, say, trying to make full auto vs. aimed shots into a "meaningful choice") is up for debate.

For gaming purposes, I'd generally recommend making it a single roll for speed of play. Just make sure that that one roll reflects the realities of how these weapons are actually used. So my suggestions are:

A double-tap or three-round burst must be declared in advance. There is no penalty to hit. Higher to-hit rolls indicate more hits. These are considered aimed attacks.
Full auto is always an unaimed attack. It takes a moderate penalty to hit, which increases rapidly with increasing range.
Sustained fire uses whatever rules you have for AOE weapons.
Aimed attacks take longer than unaimed attacks, which must be significant within your rules in a way that influences turn order.

TuggyNE
2013-07-07, 05:20 PM
That doesn't really reflect reality. People generally fire multiple shots in the hope that at least one hits, so firing three rounds at a difficult target makes sense. That's why we have a "burst" setting on the M16.

Don't try to make it one roll. Roll for the first shot as normal, and each additional shot at a cumulative penalty. Big, high recoil weapons will have a bigger penalty.

That way, a single shot has the best chance to hit, but if you have a lousy chance, three shots at lousy -1, -2 and -3 have a better chance of putting some metal on the target.

Yeah, I'd agree with this, since it's a more faithful simulation of what's actually going on; single-roll to-hit calculations don't really give the right picture.

Gnoman
2013-07-07, 07:37 PM
Everything I know about this topic probably became obsolete before I was born, but I'm bored, so...

As I understand it:


Most rifle-calibre man-portable weapons are extremely hard to control on full auto -- both the M16 and FN FAL have had their full auto capabilities removed (by at least some users) on the grounds that it proved more of a threat to low-flying aircraft than to enemy soldiers.



M14, not M16. The 5.56mm round is low powered enough that it's actually reasonably controllable on automatic, though it's still a sub-optimal use as far as accuracy is concerned. Full-auto capability was removed in the later models for reasons of ammunition conservation, as it was far too easy for nervous soldiers to waste entire magazines at marginal (or imaginary) targets.

Raum
2013-07-07, 09:11 PM
Well, I'm optimistic on the system....What are your system design goals?

Not sure it makes for a good game but putting multiple bullets on multiple targets isn't as hard as many think. I've seen competition time under 3 seconds for hitting five targets while starting holstered. Amateur competition by the way, the national competitors are faster (http://www.youtube.com/watch?v=XOYUtgSTXkE). Shooting fast and accurately simply takes practice - you have to tie it to muscle memory.

I'd suggest getting your system to work smoothly at what you want it to do and, if you want to be somewhat realistic, tie targeting speed to the firearms skill - better yet, a specialty in a given weapon. That presumably shows the time put in to learn the speed. I do recommend making it diminishing returns - it takes dedication to be the best.

Autolykos
2013-07-08, 04:36 AM
I'd suggest getting your system to work smoothly at what you want it to do and, if you want to be somewhat realistic, tie targeting speed to the firearms skill - better yet, a specialty in a given weapon. That presumably shows the time put in to learn the speed. I do recommend making it diminishing returns - it takes dedication to be the best.That looks like a solid idea for semi-auto, but I don't even think it's necessary. At some point recoil is so high that you'll miss anyway. And higher skill with the weapon means that will happen later. I think a recoil penalty is a reasonable abstraction, even though it's technically not (only) recoil that makes you miss.
But since one-shot accuracy and quick-fire are two different things, you could add a quick-fire perk/specialization that allows you to ignore some recoil with the weapon.

Raum
2013-07-08, 10:20 AM
That looks like a solid idea for semi-auto,You'll note double action revolvers were used in the video as well.


but I don't even think it's necessary. At some point recoil is so high that you'll miss anyway. And higher skill with the weapon means that will happen later. I think a recoil penalty is a reasonable abstraction, even though it's technically not (only) recoil that makes you miss.Recoil does matter, just not as much as many seem to believe. At some point in your training you're no longer consciously aiming - it becomes muscle memory. Do note, I'm talking center mass targets under 20 yards. Long range precision shooting is a different skill.



But since one-shot accuracy and quick-fire are two different things, you could add a quick-fire perk/specialization that allows you to ignore some recoil with the weapon.Not a bad idea, though I'd limit it to short range.

Knaight
2013-07-08, 01:01 PM
That way, a single shot has the best chance to hit, but if you have a lousy chance, three shots at lousy -1, -2 and -3 have a better chance of putting some metal on the target.

An alternate way to do this would be to simulate it with one shot at a bonus, then have multiple hits come from beating the target number by more. Say your default shot is 3d6+0. With a three round burst, you might have 3d6+3, and you hit once if you beat the target, twice if you beat it by 6, and three times if you beat it by 12. Landing all three shots is unlikely at a target that is at all difficult, but getting one past is very doable. Then, carefully aiming could produce something like 3d6+6, making it more likely to land that one shot but being limited to that one shot (with the downside likely coming in through the turn system, on account of how it takes longer).