I fitted a new indexing post to my Ultimate Sporter today. The pin that engages the slot in the cam plate is a tight friction fit in the post and needed to be moved - just enough to clear the back plate but not so much that it deflects the cam plate. The pin in the original version floats in the post. I don't know why the new one is made as a tight fit but I can't see it will be a problem once properly located.
The mags index nicely now with the pawl sliding smoothly over the mag on the downward stroke, so no gouging of the mag in future.
