[fuzzywolly]

1. Tighten the mag catch screw: If it is loose, it will cause misfeeds. If it is too tight it can cause problems as well though.
2. Check the bucking: If ripped, obvious issues. If it is inside the chamber and squished because it was installed a bit "off" you will get misfeeds.

 

[fuzzywolly]

Check the bucking while it is still in the chamber. Don't be certain...be 100% positive before moving on to considering it being something else.