I am curious, I have never shot any of those Winchester promo shells but I have seen them around my club. Do they have a fiber base wad? Do they have a plastic base wad? It would be interesting to compare the hull in the picture with another one.
If that is the Winchester "Super Target" loading they advertise it uses a one piece hinged wad (whatever that is). It makes me wonder if the wad could have broken at the hinge, shot cup and shot exiting normally but lower part of wad, the gas seal stuck in the bore????????? I would not think so but obviously something out of the norm happened.
https://winchester.com/Products/Ammu...Target/TRGT207