Ok thats cool, to put it in context (and so the reason I asked) is that the implant weapon will occupy the whole lower arm more or less and my thinking was that it made it very simple to point and fire, but I am more than happy to accept the penalties.
In terms of mechandrites I more meant how wold they compensate in terms of normal hand actions, as obviously he will be limited in his actions with one hand, so for things like climbing ladders, reloading etc. Things other than mechanical interface which they obviously provide a benefit.
Again for context the character is a Phaenonite Inquisitor, the controlling hand of a large sub-sector crime syndicate, as well as being in connection with a radical tech-priest, who is not fully aware of the Inquisitors allegiance, so thinking him only a minor radical.
Cheers all anyway

Ps. I hope it doesn't come across that I'm just trying to cheat my way out of penalties, thats really not why I'm asking. Sorry if it comes across as that though.