Burst fire (firearms) for sci fi setting

[1Forge]

So I'm making a sci-fi/modern rule set that uses firearms heavily, and the issue of burst and automatic weapons has been coming up mid session a lot. The DMG rules for burst fire don't work very well (target makes a DEX saving throw vs a fixed DC). So I was wondering if anyone out there with further experience (either with combat IRL or with RPG's) could help me figure out a fair way to deal with burst fire.

Preliminary ideas: When firing multiple bullets the player is generally firing at one thing so it's one attack. Firing in bursts or in a stream is usually used to increase the odds of hitting a target, increasing the damage caused to the target, and or hitting multiple targets/suppressing a target. So a rule should take each part into account.

Any Ideas or tips?

Edit: I do understand the difference between firing in bursts of three or four shots, firing a fully automatic weapon, and using cover fire. These are just all the uses I can think of for firing multiple bullets down range at a single target or area.

Edit2: Firearms in my setting follow a similar bend to the DMG but are slightly different. In general modern firearms do about double damage when compared to a martial melee weapon, and advanced weapons (such as lasers) do about three times. (everything is more deadly) for more details on the WIP rules check this page on the forum: http://www.giantitp.com/forums/showthread.php?513264-D-amp-D-5e-Sci-Fi-supplement-overhaul

[Knaight]

I'd probably separate these out a bit - suppression fire and just burst firing at one target are not the same thing, and suppression fire and going for an area are also different (plus, some of these are a bit more towards the fully automatic end than the burst fire end anyways). So, that sets up a few options.
1) Burst Fire: Get Advantage on the roll, in exchange for spending more ammunition.
2) Suppressing Fire: Target a piece of cover as an action. If anyone behind that cover moves or attacks, get an opportunity attack.
3) Area Attack: A Dex save against a static target (calculated in a way similar to spell DC, something like 8+Prof+Dex) should handle this.

[1Forge]

I'd probably separate these out a bit - suppression fire and just burst firing at one target are not the same thing, and suppression fire and going for an area are also different (plus, some of these are a bit more towards the fully automatic end than the burst fire end anyways). So, that sets up a few options.
1) Burst Fire: Get Advantage on the roll, in exchange for spending more ammunition.
2) Suppressing Fire: Target a piece of cover as an action. If anyone behind that cover moves or attacks, get an opportunity attack.
3) Area Attack: A Dex save against a static target (calculated in a way similar to spell DC, something like 8+Prof+Dex) should handle this.

Thank you for the comment! A few bits though,
1) Might there be a way to account for the chance that multiple shots hit with burst fire? (something like after a hit roll again to see if any other bullet hit?)
2)I like it (though I also might add a fixed saving throw vs fear (for low levels primarily)
3) I'll playtest this idea at my next session and see how it goes.

[Ninja_Prawn]

2) Suppressing Fire: Target a piece of cover as an action. If anyone behind that cover moves or attacks, get an opportunity attack.

This is functionally the same as readying an action to 'shoot if anyone moves from that piece of cover'. It might be worth introducing a 'pinned down' status condition to simulate this better.

I generally agree that full-auto area attacks should force the targets to make Dex saves; that's what we did with our gatling gun (http://mfov.magehandpress.com/2016/12/firearm-rules.html).

Burst fire is an interesting one. I'd be tempted to give multiple shots per attack (stacking with extra attack), but all at disadvantage, though I concede that the maths would take some balancing.

[Admiral Squish]

Two vague thoughts:
Firing a burst is a ranged attack, and it's a single attack roll per 'burst'. If the attack roll hits, roll something like a 1d6 or 1d8 to see how many shots hit, then roll the damage/bullet. Bonus damage from abilities only applies to the first bullet in a burst.
Like the first, but slightly less random. Give burst weapons a 'recoil' number. It's still a single attack roll per burst, but for every [recoil number] you beat the target number by, an additional shot in the burst hits. So, if you hit the target dead on, one bullet hits. If you beat it by [recoil number]x3, four shots hit. Weapons with lower recoil generally deal less damage/shot, but the more accurate you are, the more shots hit.

[Knaight]

This is functionally the same as readying an action to 'shoot if anyone moves from that piece of cover'. It might be worth introducing a 'pinned down' status condition to simulate this better.

Then I worded it poorly - I was going for an action where you get to shoot everyone who moves from that piece of cover.

[1Forge]

Then I worded it poorly - I was going for an action where you get to shoot everyone who moves from that piece of cover.

I think everyone is reaching a consensus, but I have one more question for the proposed method. I want to apply another effect of suppressing fire to account for the psychological effect on a soldier behind cover (after all no one wants to get shot, and shooting back means you have to get out of cover).

I propose they make some kind of will saving throw vs an effect. That being said how do you guys think the DC of the suppressing fire should be handled? (Off the top of my head the options seem to be a fixed DC that becomes irrelevant at later levels or crippling at early levels, or a skill based DC that causes one to wonder how suppressing fire becomes more scary in some peoples hands.)

As for the effect in question both fear, and stunned could apply, though a new condition could be added. Which condition do you think is most fitting in this situation? (also might rolls on the madness tables make sense for critical failures on the save?)

[Knaight]

I think everyone is reaching a consensus, but I have one more question for the proposed method. I want to apply another effect of suppressing fire to account for the psychological effect on a soldier behind cover (after all no one wants to get shot, and shooting back means you have to get out of cover).

I propose they make some kind of will saving throw vs an effect. That being said how do you guys think the DC of the suppressing fire should be handled? (Off the top of my head the options seem to be a fixed DC that becomes irrelevant at later levels or crippling at early levels, or a skill based DC that causes one to wonder how suppressing fire becomes more scary in some peoples hands.)

As for the effect in question both fear, and stunned could apply, though a new condition could be added. Which condition do you think is most fitting in this situation? (also might rolls on the madness tables make sense for critical failures on the save?)

I'd be careful about this - it is effectively the start of a morale system. With that said, I'd propose another two options.
1) Proficiency Check against a standard DC. Bounded accuracy means this affects everyone, but it affects high level characters less. Tying it just to Proficiency makes it more a factor of combat experience than anything, and none of the attributes fit too well.
2) Weapon specific DCs. Someone using a rifle on burst fire is a bit easier to push back against than someone using something like a vehicle mounted machine gun.

[1Forge]

I'd be careful about this - it is effectively the start of a morale system. With that said, I'd propose another two options.
1) Proficiency Check against a standard DC. Bounded accuracy means this affects everyone, but it affects high level characters less. Tying it just to Proficiency makes it more a factor of combat experience than anything, and none of the attributes fit too well.
2) Weapon specific DCs. Someone using a rifle on burst fire is a bit easier to push back against than someone using something like a vehicle mounted machine gun.

To prevent it from taking over combat perhaps after a certain amount of successes either players become desensitized or at least less phased by suppressing fire? (like succeed 3 times and you have advantage on all future saving throws?)

[Knaight]

To prevent it from taking over combat perhaps after a certain amount of successes either players become desensitized or at least less phased by suppressing fire? (like succeed 3 times and you have advantage on all future saving throws?)

Considering that it takes an action every turn to suppress and any decision to suppress is also a decision not to just shoot somebody I wouldn't be too worried about it taking over combat. It's likely to become a significant part, but that's fine.