Well, he is really good at shooting things. . .
There is nothing there that bothers me or jumps out as "I would do this different".
If I have a constructive criticism it would be that he may be a little too focused. It really depends on the campaign. You are very good at shooting holes in things, shooting bigger holes in things, and thowing grenades. In some campagins thats all that is really called for. In others, well, your character doesn't really have a secondary skill set to offer. Certainly he would have learned something else in the military, like fiirst aid, or demolitons, maybe a little close combat skill for when the situation calls for a more subdued response. Personally, i think you would want something to do when the situation didn't call for airing out the room with automatic weapon fire.