With the unloader idea, are you planning just a pusher or you thinking more mechanical like a wheel? I designed a quick and easy to print pusher which I think I showed you before but never did get around to making a more mechanically involved one.
if your mag only holds like 110 and you ever fill it. like you set up to 120 will it stop automaticly or will it pop mag out and dump rest of the bbs on the floor ?