I miss the old Full House HA lol back in MHGen Full House III used to fill a lot faster but also you can quickly swap ammo right after shooting which makes Striker LBG is decent pick with the true Nakarkos LBG, or the explosive gimmick with the Lost Musket
curious choice of weapon, when i think about pierce 2/3 lbg the first thing that comes to my mind is mizu/soulseer lbg for its better raw and clip size, but i can see the reason boltreaver's affinity would also work, considering narg's hitzone