[Ted Fast]

So maybe I have missed a FAQ/errata somewhere but what are the rules for which guns can benefit from a Gas-Vent system?

SR 20th Anniversary Core Ruleooks says on page 322

Gas.vent systems can be built into machine pistols, SMGs, assault rifles, and machine guns.

But the Auto-Assault 16 shotgun from Arsenal (page 28) has a Gas-vent system rating 2 as a standard mod.

Did I miss something or are the rules for the Gas-vent accessory and mod different?

[Mirikon]

Specific rules > general rules. There may be specific guns outside of those listed that have gas vent, but that does not mean other guns of that type can have it. Just like there's one sniper rifle that you can use in non-sniper situations without the Edge test to avoid a cumulative -1 each time you use the gun, or one light pistol that treats BF recoil like SA recoil..

[Medicineman]

in SR3 (IIRC) you could use a gasvent on Shotguns if you used solid Slugs instead of Shotgunshells
(maybe they carried it over to SR4 in this special case ? )

with a solid Dance
Medicineman

[Lysanderz]

I miss Big D shells from SR3. Something was really fun about turning your shotgun into a single turn flamethrower to flush out gangers from a crack house.

[Ted Fast]

in SR3 (IIRC) you could use a gasvent on Shotguns if you used solid Slugs instead of Shotgunshells
(maybe they carried it over to SR4 in this special case ? )

with a solid Dance
Medicineman

Never played SR3 but that isn't a half bad rule. I might use  a rule similar to that.
The rules for using buckshot in a shotgun is something I'd prefer never to have to use.

I miss Big D shells from SR3. Something was really fun about turning your shotgun into a single turn flamethrower to flush out gangers from a crack house.

Are you sure that there isn't ammo like that in SR4? Crazy ammo like that seems like a really SR thing. Maybe I'm thinking of Neotech.

Specific rules > general rules. There may be specific guns outside of those listed that have gas vent, but that does not mean other guns of that type can have it. Just like there's one sniper rifle that you can use in non-sniper situations without the Edge test to avoid a cumulative -1 each time you use the gun, or one light pistol that treats BF recoil like SA recoil..

Thanks for clearing that up for me. I might house-rule differently but it is always good to know what the basic rules are.

[Michael Chandra]

Given how Arsenal introduced Burst-Fire shotguns, I'm surprised they didn't rule that shotguns can also be equipped with gas vents.

[RHat]

Arsenal also offered new Burst Fire pistols and the Firing Selection Change mod, but specifically left Gas Vents as they were.  This can be assumed to be intentional.

[Mäx]

I miss Big D shells from SR3. Something was really fun about turning your shotgun into a single turn flamethrower to flush out gangers from a crack house.

Here's one SR4 version of those:
Dragonsbreath rounds
These shells use low-explosive propellant charges to expel burning powdered zirconium out of the barrel, basically turning the shotgun into flamethrower.
When using these shells use tazer ranges and the gun can only fired in SS mode.
6P -half I 12R 140¥

[Lysanderz]

I like it. Sounds like I'm gonna run this by the GM and pick me up a box.

[Reaver]

What's interesting is both hero Lab and Chummer let you add a gas vent system to pistols of all types.

[RHat]

What's interesting is both hero Lab and Chummer let you add a gas vent system to pistols of all types.

Hero Lab and Chummer are not rules references, so I'm not sure what's interesting about that...

[Michael Chandra]

Hero Lab offers quite a bit of freedom for GM interpretation and rulings. I can throw programs onto nearly everything electronic, for example. Doesn't mean a GM would allow it, but it means I could rule "okay, if you pay for it you can have Encrypt running on that Micro-Tranceiver but the program is not compatible with commlinks and the thing can't run other programs."

[Novocrane]

I don't see why you would rule it that way. Peripheral nodes are only able to use software they are designed to use, not the other way around.

[Michael Chandra]

Honestly, at a 600-nuyen pricetag, does the difference matter?

[MadBear]

In SR5 combat, recoil  now carries over from IP to IP, so there is good reason to add recoil to even SA pistols. Yes, IP to IP. So if you accrue 3 [ts recoil in one IP and then fire three more shots the next IP, you have a total penalty of -6(before comp). That penalty resets as soon as you spent an IP NOT firing the weapon. SS weapons, btw, don't suffer this cumulative penalty but can't ever fire a burst like SA weapons can.
You get recoil comp = 1/3 your STR added to weapon recoil comp, so unless you are firing bursts you can usually go a couple of rounds before you have a problem.