Ah yes, those clips. As I remember I just ground them off - no more problem. Anyways, Precision Reloading has the short kit if you're going to buy one. They also make round brass spacers for the 12 and 20. If one had a metal lathe they would be simple to make for any gauge. If you go here you can view them
www.precisionreloading.com - go to shotgun reloading, then mec presses, then mec accessories, then on the second page you'll see the brass spacers.