sarduy, watch it again, on every crate of weapons, every gun the 10-rings guys had, if you look close you will see the stark enterprises logo on the side, I thought it was pretty obvious...
Stark was a weapons designer, the first one that is, pappa stark built the company suppling arms and high tec weapons to the military, Obo stane took over after he presumeably was responsible for Stark Sr.'s death, Stark Jr. when he came of age continued the tradition his father had started, to develop and supply weapons to the military to fund his other projects.
problem was that his other projects slowly got put on the back burner until he was nothing more than a weapons dealer.
Stark made the missles, Stark made the Guns, Stark even made the land mine's.
that was the entire point of the movie, Stark the man was trying to come to grips with what Stark the company was doing.