Like how muzzle attachments can change ammo speed, weapon recoil and weapon dispersion, have the ability to create muzzle attachments that can change the submunitionConeAngle (and maybe other submunition properties that make sense). The idea for this is that so a choke attachment can be added to a shotgun that would decrease the spread of a pellet ammo.
Or in other words making MagazineCoef, AmmoCoef and MuzzleCoef effect submunition projectiles