Everytime I hear "He has a Howitzer for an arm," I chuckle. A pure howitzer (not the later Gun-Howitzers, like an M110A2) like a 75mm Pack Howitzer, this definition applies:
how·itz·er
ˈhouətsər/
noun
a short gun for firing shells on high trajectories at low velocities.
Sounds like Jacory...