Fires a large cannonball (damage partly blast damage). Additional projectiles will increase the size and damage of the cannonball instead of adding additional projectiles.
Mods like Splinter could still function but dont know how Barrage would work, maybe by dividing the projectiles into smaller projectiles while still thinking about the weapons unique perk.
Negatives should be quite slow rate of fire. Don't know by how much the damage should increase per added projectile.