User blog comment:Kogath/Monster Hunter: World Discussion/@comment-6050823-20170826140239

Heavy Bowngun


 * There were two Heavy Bowguns (Bone Shooter and Steel Assault) in the demo for Monster Hunter: World. Both Heavy Bowguns had a special type of ammo. The Bone Shooter had a Sniper type of ammo and, while the Steel Assault had a Gatling Gun type of ammo.
 * A gauge is used to show the special ammo. Once a hunter starts using the special ammo, the gauge will decrease before slow refilling overtime.
 * Even if you switch ammo while fully loaded, you won't have to reload the weapon again.
 * Now if you're out of range from a monster, the Heavy Bowgun's reticle will indicate this.

Source: https://www.famitsu.com/news/201708/26140477.html