Try using another Bolt.
The problem with building a 80% Ak is that the Headspace is set by the Barrel being pressed in to the right point and then Drilling and putting the Barrel retaining pin in.
Sometimes these kits were demilled because of this very issue and I why you must always check headspace on a Kit build Period.
If the headspace is off he can set the headspace with a Barrel press and then use a larger barrel pin after redrilling the barrel pin hole as this is the best option.
I had to do this on a few of my builds to get headspace right, YMMV and this is posted for its Entertainment value only.
Thanks!
I passed that info along and he said "eh, I stopped caring about 10 minutes after I built it. It's gonna keep assisting gravity in holding down that back corner of the safe for the rest of its life. And I don't want another AK."
I, on the other hand, hate to see projects linger in an unsatisfactory state. It's not even MY project and it bugs me. Maybe at some point I'll get him to torch the receiver and let me have the parts so I can redo it right - with the help of someone here who knows WTF they're doing.