You'd have to be stupid to R&D your own weapons of war in this day and age; not when so much of the US GDP is spent on doing that for you; AND nearly everything we make is available through normal or grey markets at reasonable rates. One might be concerned about kill switches or backdoors; but i'm not sure anyone else worries that much about our cyberwarfare units.
I really am just waiting for us to start cutting out the middleman and start renting out chunks of the armed forces for whatever little shitshow someone want to put on. We currently supply most of the hardware, and the 3rd party ex-mil contractors as it is, so its only that small step further; for quite a lot of financial gain.