Winchester bulk pak ? , we've had that same problem for quite some time, does the same in my Benelli , 930, MKA 1919, never had a lockup that bad, but routinely they would come out WITHOUT most the lip for the extractor to grab, Yes the SWELLED that much, or the "brass" was split.
Quit buying Winchester about a year ago, Win AA's NO problems
Thats good to know