>>6143691I've got a feeling you're issue lies with the fact it's one of the old ass MGs. I built a bunch of MGs fine, but my Shining Gundam build was a piece of shit, with one of the shoulder joints just snapping in half, and none of the screws working properly.
I'd say you'd be fine with a newer MG, get yourself something nice and simple like the RX-78-2 or GM Sniper 2 or something.