I was having these exact problems today in a competition i participated in. The gun cycles and loads another shell but wont fire the next one. I've never had problems like this before but in this competition i was supplied with the ammo and wasnt able to bring my own...
I took the bolt apart and noticed the same steep angle mentioned here, i filed it down somewhat and now "rotating part" moves much easier and should be enough to fix this problem. (I will report my results when ive done some shooting).
I wanted to reply to this post since theres no other replies and this seems to fix this particular problem.
