To further the argument... IMO, the genius behind the .327 Federal as a possible defense round isn't merely in the 6th shot over 5, it's the reduced felt recoil of a round that puts out more energy than a .38 Special +P and does it without the numbing shock of a .357 Magnum.
Will the .327 Federal anchor a horde of bad guys? I have no idea and if there is any street data on the actual on-target performance of any of the .327 Federal loads on bad guys, I've not seen it... I really, REALLY don't know.
But IMO, that's the main draw of the new round. Not just the 6th shot.
Attention Brass rats and other reloaders: I really need .327 Federal Magnum brass, no lot size too small. Tell me what caliber you need and I'll see what I have to swap. PM me and we'll discuss.