Airsoft gun Clip modification

[Biolore]

So, I've got a firepower A47 Beta (http://www.airsocom.com/47390B6.html), and the crank for the clip broke. The shaft that it would plug into fits a 3mm allan wrench perfectly. I want to mount a small motor that can run the gear to load the airsoft gun while I hold the trigger. I'm Not sure where to get one, and that so far is my only problem

The motor would be around 120 rpm speed I think, and a somewhat low torque so it doesn't break the clip, likely with an either a keyed axel that can hook up to the proper allan, or a 3mm hex axel.

I figure this is the best place to ask.