This thread sure highlights the reason for using flanged cartridges in doubles on DG IMO.
Take a pair of 500 3 inch NE cartridges and they'll almost find their own way into their chambers without having to worry about pushing and sliding and whatever else.
This "locating" the extractor pawl into the groove business, must surely cost time and create a possability of a fumbled reload IMO.

OK for non serious use but not really desirable for game that has a high price tag or a bad disposition.