Galaxy

So I got this M3 from gunbroker, had really huge trouble putting two assembly together. The receiver is already a little broken due to my efforts blute forcing the barrel assembly in, but the small block on the end of the chamber extension just doesn’t want to go into the groove on the receiver. And then I found this on the barrel assembly and I kind of think the chamber extension is timed wrong. Am I just doing something wrong? Does everything look… correct? https://imgur.com/a/bcTgpGY