A successful 3 round burst

[Sorenant]

As far as I know most burst fires are there to save ammo, not hit a target with more bullets, so the current GURPS mechanics seems good. In a range you have all sort of bonus that allows you to hit a target with more than one bullet but you'd be hard pushed to repeat the performance in a real firefight.
For guns that uses burst fire with the intend of actually hitting multiple shots, like AN-94 and G11, GURPS already accounts for them in HT83 by reducing recoil.

Edit: I just noticed none of the UT slug-throwers has high-cyclic controlled bursts. If I recall correctly UT came before HT, so that would explain it.

[Anthony]

Originally Posted by Sorenant

As far as I know most burst fires are there to save ammo, not hit a target with more bullets

Burst fire is to increase the odds of hitting a target with one bullet; the evolution of the modern assault rifle basically assumed that only a single rifle bullet hit was needed (and in GURPS, if you hit a target wearing Vietnam-era body armor with a Vietnam-era M16, one bullet very probably does the job).

Burst limiters are for saving ammo.

[OldSam]

Originally Posted by Ulzgoroth

But 'right where you point it' isn't necessarily where you actually want it! [...] It's entirely possible that the first shot isn't quite on target, but one of the later ones finds its way to where it's wanted.

But then you're talking about gun shots IRL, not about GURPS rapid fire rules, right? The question was specifically about 3 round bursts, IMHO in GURPS terms that would be a single rapid fire attack with RoF 3 (three shots / bullets). Going with a single attack role like that, it's not possible that the MoS of shot 2 or 3 is better than the first shot... (*)

*: Of course, it would probably be ok to allow rolling separately for each single shot (though this is not RAW AFAIK), _then_ something like that could happen mechanically, e. g. rolling a critical success for the 2nd projectile. Certainly results in slower game performance, but it could have some advantages regarding realism at times.

[Ulzgoroth]

Originally Posted by OldSam

But then you're talking about gun shots IRL, not about GURPS rapid fire rules, right? The question was specifically about 3 round bursts, IMHO in GURPS terms that would be a single rapid fire attack with RoF 3 (three shots / bullets). Going with a single attack role like that, it's not possible that the MoS of shot 2 or 3 is better than the first shot... (*)

*: Of course, it would probably be ok to allow rolling separately for each single shot (though this is not RAW AFAIK), _then_ something like that could happen mechanically, e. g. rolling a critical success for the 2nd projectile. Certainly results in slower game performance, but it could have some advantages regarding realism at times.

GURPS doesn't have a MOS for the second or third shot. It has a MOS for the entire attack, which determines the number of shots from the attack that hit, but not which shots.

P31 of Tactical Shooting has a section titled "Attacks with Mixed Ammunition" that discusses this.

EDIT: from said section:
"It’s irrelevant in which order the different
rounds are fired, partially for playability, but also because
GURPS does not assume any particular preference in which
rounds of a rapid-fire or multiple-projectile attack hit. In the
span of a one-second turn, it doesn’t matter."

[OldSam]

Originally Posted by Ulzgoroth

GURPS doesn't have a MOS for the second or third shot. It has a MOS for the entire attack, which determines the number of shots from the attack that hit, but not which shots.

P31 of Tactical Shooting has a section titled "Attacks with Mixed Ammunition" that discusses this.

Ah, ok, thanks, makes sense in that way!

So in the end the order of the rounds is normally GM interpretation, in case that even matters. I'd probably still stick to the simple version "first projectile is normally the most accurate" as a quick default (most basic), but obviously it is very good to have other explanations, too, as situations differ. And yes, as it's said in TS, usually it's not really important anyway...

[Plane]

Originally Posted by johndallman

You can, for example, start by aiming a little low and let muzzle climb scan the burst across your target.

Is this anything like "Walking the Burst" on TS16?

Originally Posted by Ulzgoroth

This is more obvious at higher rates of fire where GURPS gives a bonus to hit over a single shot.

That's the key thing right there.

It's really useful to know which bullets hit if for example you have different rounds (like a magic bullet in your clip) so it seems like MoS-based bursts can't give us that.

The only way I can think is to actually have 1 distinct roll per bullet. It's super-crunchy but I can't think of another way.

Originally Posted by Ulzgoroth

P31 of Tactical Shooting has a section titled "Attacks with Mixed Ammunition" that discusses this.

EDIT: from said section:
"It’s irrelevant in which order the different
rounds are fired, partially for playability, but also because
GURPS does not assume any particular preference in which
rounds of a rapid-fire or multiple-projectile attack hit. In the
span of a one-second turn, it doesn’t matter."

I could see it mattering with certain abilities...

Like for example if you had a 2-round clip, one containing a lead bullet and one containing a silver bullet.

I have DR (limited: silver bullets, absorbtion +80% heals HP, reflexive)

If I get hit by Lead-then-Silver, then I'm injured by the lead then instantly healed.

If I get hit by Silver-then-Lead, I have nothing to heal so the absorbtion is wasted, and then I take the lead injury.

[Sorenant]

Originally Posted by Plane

It's really useful to know which bullets hit if for example you have different rounds (like a magic bullet in your clip) so it seems like MoS-based bursts can't give us that.

The only way I can think is to actually have 1 distinct roll per bullet. It's super-crunchy but I can't think of another way.

Why not just roll a dice to define which bullet connected? 1-2 means the first bullet hit, 3-4 means the second one did and 5-6 for the third. If the player wants better chances, maybe let them buy a leveled perk that grants 1 impulse buy point for this purpose.

[Ulzgoroth]

Originally Posted by Plane

Is this anything like "Walking the Burst" on TS16?

Not really, no. Walking the burst involves observing the fall of your shot and using that to correct, not sweeping your aimpoint in hopes of increasing the chance that it lays some rounds where the target is.

Originally Posted by Plane

It's really useful to know which bullets hit if for example you have different rounds (like a magic bullet in your clip) so it seems like MoS-based bursts can't give us that.

The only way I can think is to actually have 1 distinct roll per bullet. It's super-crunchy but I can't think of another way.

Maybe you should read that section, because it has a way and the way is not that. (It's pretty crunchy, but a lot better than one roll per bullet in some cases.)

Originally Posted by Plane

I could see it mattering with certain abilities...

The statement that order is not relevant (like most statements) should be taken to pertain to the context in which it is made. Not every possible context you could transplant it to!

Whichever rounds hit, it's usually safe to presume they hit in the order they were fired. Which for typical situations is clearly defined, though it could be confusing for multi-barrel weapons. Or if you loaded a multi-shot projectile with a combination of shot types.

[Anthony]

Originally Posted by Ulzgoroth

Whichever rounds hit, it's usually safe to presume they hit in the order they were fired. Which for typical situations is clearly defined, though it could be confusing for multi-barrel weapons. Or if you loaded a multi-shot projectile with a combination of shot types.

The more common (though still rare) situation is where you have multiple ammo types and you need to know which of them hit (I have 1/3 silver for werewolves, 1/3 cold iron for fey, and 1/3 armor piercing for rampaging robots; I only got one hit). Can probably just do it randomly, though.

[Ulzgoroth]

Originally Posted by Anthony

The more common (though still rare) situation is where you have multiple ammo types and you need to know which of them hit (I have 1/3 silver for werewolves, 1/3 cold iron for fey, and 1/3 armor piercing for rampaging robots; I only got one hit). Can probably just do it randomly, though.

Doing it randomly is appropriate but can be non-trivial when you've got types mixed in odd ratios, and maybe some of them have accuracy modifiers or different Rcl values...

Which is what the Tactical Shooting section is mostly handling.