G&G L85a2 upper receiver jumps out of alignment

[andersson]

I've got one of the earlier G&G L85 that has developed a wobbly upper receiver. Tightening the steel walls on the receiever around it helps, but instead of wobble the upper becomes spring loaded and jumps out of alignment. Holding it by the grip sideways makes one side jump out of alignment to the point it's canted. It's then very hard to force it back in its place. Tightening the sheet steel more makes it stick up and the upper sits on the edge of the lower receiver. This is only a problem in the front where it's supposed to hook around the selector tube. I've tried to shim the hook with electric tape without much success. I did small patches of tape inside the hook where it makes contact with the underside of the selector tube, then a larger one over the small patches of tape and the rest of the inside, in the hook.

This is obviously not good because the inner barrel and whole gearbox gets canted or bent.

Any ideas? I believe it might be that the electric tape is too soft, but adding to it tears it off while disassembling it. Could it be a screw somewhere I'm missing? 

Pictures (Tried my best) First two are just after assembling it;

Second two are after just holding it;

The inside without any tape

 

[ButcherBill]

Might not be relevent but in my A1 it has a 'bracket infront of the magwell that the body pin secures, it's designed to hold the upper securely to the lower in the middle. It's a pain in the arse to fit so I removed mine.

Here's a YT vid that shows what I mean, hope it helps...