A weapon system comprises a firearm configured for discharging ammunition having multiple projectiles and a sighting apparatus integral with the firearm. The sighting apparatus outputs a beam of light having a generally round shape. The sighting apparatus is oriented such that a centerline longitudinal axis of a barrel of the firearm extends through the beam of light. The sighting apparatus includes a light beam size selector for allowing a cross-sectional size of the beam of light at a fixed reference location external to the sighting apparatus to be selectively adjusted by a shooter of the firearm to a plurality of different cross-sectional sizes.