[DrAnders]

Hello fellow Shadowrunners,

I am working on some homebrew rules for allowing multiple gun attacks against a single target, I am considering the following:

The number of bullets exceeding the first bullet imposes a -1 on defence, meaning declaring multiple attack against a single target with the complex action long burst imposes -11 defence, but with the damage of a single gun and potential for double ammo modifier (-10 armor pen for double APDS ammo, but also +4 dmg / +10 armor for using flechette).

My idea is, that the attack requires the attacker to split the dice pool, since he is using two weapons it would make sense that the accuracy is halved.

Summary for the rule:
Pros
-1 defence for every bullet beyond the first (better than a single full auto weapon)
Double bullet modifier
Cons
Half dice pool (less hit potential and higher risk of glitching, makes sense in a roleplay aspect too)
Damage value of a single gun applies (lower one if they have different DVs)

What do you guys think, this probably needs some fine tuning. Thanks in advance.

[Glonthein]

So instead of having each attack dodged and soaked independently, you would join them as one massive attack with double dodge penalty and ammo effect. First, we agree here that you are using two weapons - so probably two uzis or something like that - because a multiple attack with a single weapon in burst fire mode would be treated as two burst fire, not two long burst.
Second, you did a little mistake, APDS rounds have -4 AP modifier, so it would be -8 in your example.
Third, this seems quite strong with most of ammos, but with flechette it truly sucks, since except if your target has literally no armor, it will always mean stun damage. If you ever face someone in mil-spec battle armor, or spirits, it will probably mean no damage because of how the hardened armor effect works.
Fourth : What happens if you use two different ammos on each weapon ? By default I guess you would add both effect, but better be sure.

[DrAnders]

So instead of having each attack dodged and soaked independently, you would join them as one massive attack with double dodge penalty and ammo effect. First, we agree here that you are using two weapons - so probably two uzis or something like that - because a multiple attack with a single weapon in burst fire mode would be treated as two burst fire, not two long burst.
Second, you did a little mistake, APDS rounds have -4 AP modifier, so it would be -8 in your example.
Third, this seems quite strong with most of ammos, but with flechette it truly sucks, since except if your target has literally no armor, it will always mean stun damage. If you ever face someone in mil-spec battle armor, or spirits, it will probably mean no damage because of how the hardened armor effect works.
Fourth : What happens if you use two different ammos on each weapon ? By default I guess you would add both effect, but better be sure.

First: Yes it would be two pistols of some kind, does a multiple attack action require  you to make a seperate attack action with each weapon, I always thought you could take a complex action like long burst for both weapons? If so, then yes two burst fires.
Second: Yep, my bad 
Third: Yeah, it kind of breaks flechette, but I have a hard time coming up with a general rule where flechette isn't hurt
Fourth: Thats why I decided to use the lower damage value, so you can't negate flechette with APDS rounds and gain +2dv. Otherwise you could mix ammo, but there's no benefit of offsetting the DVs.
 

[Glonthein]

About 1) Core says that, when using a single weapon to do multiple attack in burst fire mode, you are doing the long burst complex action, but you must divide the bullets between the attacks, so it is treated as two burst fire. But yes, when you use two weapons, if you want to do a multiple attack in burst fire mode, you can indeed use long burst on both weapons, in which case each attack is a long burst. Be cautious with the recoil, because it is going to go up like crazy, but you can make it work.
Which reminded me, if a character who doesn't have the Ambidextruous quality uses you houserule, how are you treating his dicepool ? Normally, you would have half of your dicepool on the good hand, and half -2 dp on the off-hand. Since you do only one roll with half the dp here, it would mean that said quality would be useless - at least in the context of that action. There may be a fix to do here.

[DrAnders]

I guess if you don't have the quality you would suffer the -2 dicepool to the overall roll, meaning half the dicepool for the roll and then minus -2 applied after the split, not before That should make it nice and even, and still make it a solid quality.

Halfing the dicepool twice seems to me, as forcing people to choose it. For the price of 4 karma, it still has a really nice payoff, compared to 6 karma for pistol II.

And thanks for all the feedback, it really helps. Hopefully it's possible to make some interesting and rewarding rules for multiple attacks, without making it incredibly overpowered like in Run&Gun.