Depends on whether you're firing slugs or shot. If you're using, say, pellet shot, you roll the weapon's dice(2) plus the extra from the ammo(6). 2 + 6 = 8 Too complicated?

Updated this a bit. I sort of borrowed ThatWhichNeverWas' idea about multi-mode spread ammo, but in a way that makes more sense to me. A shotshell has to stay more or less in one piece as it travels the length of the barrel, otherwise the pellets start rebounding off the inside and kill the muzzle velocity. Modern shotguns have a concave wad at the back that helps accomplish this, but that mechanism doesn't really work with EP's caseless ammunition - it also imposes an upper limit on rate of fire, as firing too fast risks the next round hitting the wad of the previous one as it exits the barrel. I think the idea I came up with more or less works. Took out birdshot, as it doesn't really differentiate itself much from the larger "buck" shot. And, pellets are a spray weapon now. I crunched some numbers and did some thinking, and I think my earlier concern - that making pellets a spray weapon encroaches too much on the shredder's combat role - is unwarranted. In addition to different AP/DV characteristics, I tweaked the combat shotgun a bit to give pellets a different range profile than the shredder. I think they're different enough that neither is necessarily better than the other. Added a seeker round option, inspired by Rastus' assorted houserules. Essentially he had the same idea that I did regarding smoothbore weapons as multi-role munitions delivery, but he went with seekers instead of grenades. As Aldrich pointed out there's no reason you couldn't do both, fluffing the latter as having a larger payload instead of propulsion and guidance systems. So grenade shells are now equivalent to standard grenades(with some physical modification), and seekers are equivalent to single-shot micromissiles. The previous grenade shells are now specifically minigrenade shells, which aren't limited to SA fire. It also occurred to me that, seeker weapons using magnetic coils as a launch system anyway, there's no reason you couldn't use seeker shells with a rail-shotgun, and that you wouldn't need a sabot or propellant to do so (unlike gas-propelled firearms). Still, the firing characteristics of kinetic weapons means they have shorter range increments than a "standard" micromissile, although this is less an issue with a rail-shotgun because it can achieve a higher muzzle velocity before the seeker's scramjet kicks in. No sabot, and thus no risk of barrel obstruction, means rail-shotgun seekers can do semi-auto fire as well. Anyway, they both use different weapons skills. Players and GMs intending to use these rules, remember you can default to a related skill(in this case Kinetic Weapons) at -30 if your shotgun-carrying Sentinel has poor Spray/Seeker ratings. Finally, grapple shot. Something which is, I think, unique in Eclipse Phase. Of course being unique means I had to write it from whole-cloth(borrowing some language from the Subdual rules on grappling), so it may need balancing.