Here is the problem with the 597.

When the bolt cycles rearward and stops against the buffer it begins moving foward again before the case can get completely out of the receiver. The charging handle smacks the empty case and knocks it right back into the receiver.

This is what you need to do. Cut the rubber buffer that is in the back of the receiver in half so that the bolt will move farther to the rear and allow the spent case to clear the receiver before moving foward again. Once you do this it should function just fine.

It took me a whole lot of shooting inside the test booth before I finally was able to figure out exactly why the case wasn't clearing the receiver.