I had the 590A1 lock up with a round chambered and got great advice here, but it's not over. I followed the advice in this thread: http://www.mossbergowners.com/forum/index.php?threads/improved-mossberg-elevator.12594/#post-166999 but I did minimal filing as instructed. When I loaded the mag tube again with high brass Rio 00 buck, as before, it resisted going in the tube. And again, the action lock lever hung up and jammed everything again. But this time, by swearing and trying to pull the lever back down while pushing the forearm forward it freed itself and I was able to cycle several rounds thru it and unload. Then I tried Rio #8 game loads (low brass) and they insert easily in the mag tube and cycle and eject perfectly. So, is the high brass thicker? It seems so. I know most every firearm prefers a particular brand of ammo. But where I live there aren't a lot of choices. There was a skeet range near here but I don't think it's open anymore. We get a 2 month dove season and while I can take a few shots here and there I really can't fire off 2-300 rounds... Is there any way I can break in this 590 other than that? I could try going back and doing a little more filing but would rather not. At times I miss the wide open spaces of the Pacific Northwest where I could shoot all day.