It's simple,realy. All you have to do is aquire a few hundred fully automatic firearms, mostly AK-47 and clones, M16 and variants, G36s, MP5s, and a grab bag of other guns. Then you go to Hollywood, build a gun vault the size of Manhattan, and hang out your shingle. It's realy simmple, you just need a few million dollars, a few tons of paperwork, and a good contacts with arms dealers.
Actualy, I have no clue, but that sounds right to me.