Looks like it. The TCP would do that with wider hollow point or cast bullets. I had forgotten that. Looks like the nose may have been bumping the tab, though why it happened ONLY on the last round is a mystery. I tried tweeking the mag lips, then filing the tab a few strokes at a time. I was working when I had to leave the range today (MASSIVE rain storm!!!) I'm going to try some handloads later this week or early next. If they cycle, we're home free. Thanks to everyone for the help and suggestions.