Right there ^^^^ What in the FUK is that shim for??? and what in the FUK is it made out of?
And my guess is you had no proper tools ,vises...or brainpower to assemble this and get it torqued down....go look up what the word torque means you nitwit
I knew something caught my eye everytime I looked at your $hit....You put a Piece of Cardboard or some piece o $hit material to shim up the barrel nut to the upper You Stoopid Fuk Head..... no wonder its about to explode and wont feed or extract Wash