Explosive shotgun rounds are single projectiles with a contact fuze with the same damage profile as a Rifled Slug but doing EXP-DMG as a S. EXP.
Technology used to produce explosive bullets during WW2 has recently been repurposed to construct explosive shotgun shells. Though underpowered in comparison to an actual grenade, a direct hit from a shotgun's explosive round can easily tear off limbs and disembowel.