This is one of the best weapons to use while on a Sky-Line since it has a blast radius and can kill enemies quickly. It also works pretty good against the harder enemies. Your limit is the ammo, but ammo can be given to you by Elizabeth when you run low.
Stats: 1250-1750 Damage, 0 Critical, 2 clip size with 8 reserve capacity.
Damage Boost 1 (Dmg +25%): First found in Inside Hall of Heroes for $385
Damage Boost 2 (Dmg +25%): First found in Emporia for $385
Clip Increase (Increase Clip to 3): First found inInside Hall of Heroes $816
RPG Speed Boost (+100% Projectile SPeed): First found in Downtown Emporia for $333
To fully upgrade the Barnstormer you will need $1919.