Yes, it's serious; and you should stop using your G-21 with such heavy loads. There's got 'a be some sort of increase in headspace on that 45; and primers are going to have a tendency to back out on ya, too. I have, long, suspected Glock breech faces of not being properly hardened and of inconsistent density. I've tried, for years, to find out exactly how and what they're made; but all I ever get is, 'from steel billets'. What kind of steel billets remains a mystery? Are they X-rayed for stress imperfections and cracks? I doubt it. Tenifer is just a surface treatment; and the overall tensile strength of a Glock's breech face remains largely unknown. Do Glock breech faces ever fail? Yes, on occasion, we already know that they do. I suppose I'm as guilty as the next guy. I've fired modest 45 Super loads in both of my own G-21's. So far, though, without any apparent ill-effects other than a little minor slide peeing. A reasonable solution? Get an aftermarket slide; and, from now on, shoot tamer loads. NOTE: Now that I think about it, nothing has been said about, 'HOW' you set this G-21 up? Your polymer frame could be, 'wobbling like spaghetti' every time the pistol is fired.