Squib308 mentioned: concur appears like an ammo difficulty. perhaps the brass is bulging? Have you ever inspected the winchester brass before vs. soon after firing? It stood in well over the 590 but a pink dot that may not formed like a box might be a more sensible choice. Any https://highimpactrounds.com/product/mossberg-590a1-spx-12-ga-20in-8rd/