It appears that at least a sample of the P97's suffer from extraction failures. Alas, do not panic if your P97 is leaving empty casings floating in the upper. The pistol re-design has fixed the many problems that prevented the PO Carbon 15 from being reliable. This problem stems from a weak spring in the extractor which for newbies is a component of the bolt that grabs the lip of the .223/5.56mm casing and holds it so it moves rearward with the bolt carrier assembly for ejection from the ejection port.
The problem is a small,little, spring that just doesn't. Alas read the following posts for the problem and solution: www.ar15.com/forums/topic.html?b=2&f=28&t=141379 www.ar15.com/forums/topic.html?b=3&f=118&t=171690&page=1
P.S. The mounting rails for the P97 that allow for optics and lights are very expensive but available now at BFI. I ordered them yesterday, but they have not shipped yet, so I don't know if they are really available.