So sorry about the form destructo. I'm forming an opinion here so thanks for the ed-e-cut lesson.
1. Dented brass is a non issue.
That was an answer.
2. The gas was an issue as was determined by Sig when I sent the gun back and they replaced the o rings for the gas return.
It got better... But still jams occasionally.
3. The short stroke is an issue as well. The m400 Enhanced has a shorter stroke as a design. I believe this is the problem. Normally this would not happen with a standard travel bolt but I think having even one system out of perfect sync makes the cycle more susceptible to error when the stroke is shorter by design.
See this: http://www.youtube.com/watch?feature...&v=mSbLragkC54
BTW I wanted the answers and I got at least two. Success.