FWIW, I've never seen a sideplate - early or late - that looked anything like his. Cannot tell if it is a shadow, but the feed track scratches certainly take a jog (and maybe a dip?) at one point. Someone appears to have dug around in there, possibly in an attempt to feed a short bullet, or even maybe blanks? I'm guessing the problem will go away with a smooth plate - the spring only provides in-line pressure - the up-over-and-in-swoopty-do is dependent on smooth, properly shaped surfaces.