You know, for one second there, I thought the OP was just too OP to come back.
Seems I was wrong.
Ok, something constructive on your gun. If something similar doesn't exist in 2070, don't recreate it. For the sake of rules, just look at similar 2070 weapons and start from there. Stick to the rules, or your whole group will start "recreating" seemingly realistic things.
That would not be a problem on itself, but with guns there is a high risk to just bust the rules. In this case resisting damage. First, you yourself (and your teammates) would probably end up sleeping and showering in your military armor, OR you'd force your GM not to attack you with anything remotely resembling a weapon whenever you don't wear said armor. Because any surprise attack would just kill you. Second once your GM starts handing out better guns (and playing his mooks clever) you're doomed, as even the heaviest of armors will not save you. In theory, GMs can always do that (and get problems with their group afterwards), no matter the rules, but you have to keep in mind that you're kind of asking for it. Even if your GM just wants to present you some sort of a challenge he risks killing you. That will do your game no good. Shadowrun rules are not about being OP, because they're not made for a computer game, but try to imply some realism, while keeping game balance. So while you're probably right about your gun, and it does exist with all your modifications, it does not in the Shadowrun universe, maybe just for rules sake.
The rest looks like a random Mary Sue attempt, so I won't comment on it. But to answer your headline:
No, in my opinion it is not OP, just bad. It has no flavor but stinks of bending or breaking rules for the sake of getting an advantage over a) your fellow players (cheesy) or b) your GM (who per definition has more pull).