troubleshooting

Hey all, my AR is still not working. Today I went to my LGS and found they were having a going out of business sale, decided to get the above pictured fore end cap just on the off chance that my gas block was misaligned with the gas port in the barrel and that's why my gun wasn't getting enough...

OK so I have struggled with this friggin thing for an hour now. It's a russian 1954 tula laminate stock SKS. Whenever I go to empty loaded rounds out of the mag the whole damn assembly falls out on me. I know you rock the assembly into place with the trigger group out, then slide the pin on the...