That's what the little openings in the side of the Navy Jet are. If you want other types I suggest you look at photos of the real thing and then change the texture (I extracted it from the .a2c file and attached it) of the model. You could also switch between textures just to make the gun appear to file.

Simple shapes can be used for "bullets" if you want that - there are several examples in the "share worlds" section of the forum.