actually if I remember. Theres a member here who had a similar problem and it was the extractor not allowing the round to sit flush on the bolt face that was the problem.
unless you have the knowledge and some form of proper tools it can be hazardous to your guns health. I did my own SBR work, swapped out the stupid smooth barrel for a gi with the cutts on it that I got for $40. when the threads broke on the first barrel it sounded like a gunshot in my garage using my 4 foot cheater bar on my jig I made.
stuff like this can be found very very low in the right spots because they're not "attractive" anymore. I got my Stevens 620 for $120 last year. took a lot of cleaning to get it running good. Took the barrel down to 18.25 cause the last few inches looked like a beaver tried eating it.
"readily convertible" IE: you cant just take it off with a screw driver or hammer in 5 minutes. most non intrusive is blind pin and silver soldering over the holes.
Not very professional That's jail for you though. yes, but since the killer was suppose to be a pro, I would of thought he "d be more creative that stuffs for the movies.
i think they use their crappiest grain of wood for the commando parts. always reminded me of what century did to the wood on all those Czech VZ-52 rifles , bastards.