Selling to governments and large corporations is probably way, way harder than selling to small businesses. Firstly, large corps will have a lot of demands on the solutions you provide and if it is weapons there is probably a lot of legal issues as well.

I don't think governments will tell people on the kind of software weapons they have. They won't simply hire any contractor.

I think it's probably a bad idea but at the same time it is not really clear on what you'll be doing.