Yes I am new here so I am seeking knowledgeable assistance with the following issue.I recently acquired a Powder Springs Mac 10 45acp. My first machine gun purchase. My problem is with several magazines "most" the gun will fire ONLY SEMI AUTO. No jams failure to feed or eject etc. It is only that with a lot of magazines that it will not continue firing. I have a Lage grip assembly with dual mag catches.I am using cut and uncut Grease Gun mags. The one magazine that works happens to be one that is cut. I would greatly appreciate help with members knowledge and any experience with this.