Multiple Gunshot Simulation

[Ozfer]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

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]

Sure, take whatever you like. If it results in another good system, it was worth it :)