[CrankTheBoost]

Last year I picked up a Classic Army metal upper and lower M15a4 receiver set, The previous owner fully disassembled the upper receiver and put all the parts in a bag.

Now I'm trying to assemble the charging handle but I can't figure out how it works, I might be missing some parts.

Does anyone have a picture of the insides of the upper receiver? Or could someone with a classic army metal receiver please take a picture?

Thanks in advance,