Down a few slots in this old post, posted about some of the things that could go wrong.https://www.gatewaytoairguns.org/GTA/index.php?topic=125934.msg1232793#msg1232793Could be a simple as the striker spring being cranked up too far...so the striker can't travel all the way back...and the "hand" can't travel down far enough to pick up the next "edge" on the magazine ("edge" being those rectangular cuts around the outside of the mag.).
Hatsan customer service email me within an hour after I emailed them. I had already tried everything they were suggesting. I called field Supply and they are sending me an RMA and will replace the rifle. I am really happy with the customer service from both Hatsan and Field Supply.