1919A4 Troubleshooting help

Guys after this weeks L.C. shoot I still have (2) minor bugs that need to be worked out. By the way this is a A.A. build, and under warranty. However if I send it back for warranty work who knows when I will get it back, plus it's a learning experience for me.

1. There were many times when the trigger would not reset. After pulling on the trigger and pushing it down I would get it to reset. When I had the bolt out one day I noticed that the sear was not moving freely. So I am thinking about removing it and polishing it. Do you guys think I should replace the trigger reset spring as well?

2. Thanks to "Lucky #13" we noticed that if we fed the belt in "single loop" first the bolt would not fully close. I would have to push the bolt forward every time to fire. Now if we fed the belt "double loop" first it ran fine until it got to the last round which would not make it to the extractor/ejector so it would never get chambered.

So is there any way to make this accept a belt fed in "single loop" first, or how can I get it to feed the last round to the extractor/ejector so it can be chambered?

Thanks for the help guys.