About this video

With this Heavy Bowgun build you and the impact mantle you can run over monsters! Try it out! If you have Glutton Assault :D
I think Nergigante was a good example for that
Played without Palico

And don't forget to eat food with the ability "Slugger"
A good HBG player will be even more fast :)

Armor Weapon Augmentation / Jewel
Tarroth Assault Glutton       Affinity + Atk
Kaiser Crown a Tenderizer + KO
Drachen Mail     Spread
Drachen Vambraces aElementless + KO
Empress Coil bCritical + Critical
Dante's Leather Boost a      Attack + Attack
Attack Charm III -
Impact Mantle