When we get the report of a home owner hitting a perp with 5 or 6 410 buckshot rounds (which means 20-24 .36 caliber holes right through the bad guy ) and it being a failure to stop I guess I'll eat my hat and join the rest of the internet in hating this caliber /chambering.
Same with me.
One has to remember that even though a 3" 410 buckshot load only has 5 pellets versus 9 pellets in a 2 3/4" 12 gauge buckshot load, the individual pellets are still moving at around the same feet per second and the pellets are the same size/weight. And contrary to popular belief, the 2 1/2" 410 shells generally have a faster speed for the given payload. You can find 2 1/2" 410 shells loaded with either 3 or 4 pellets of buckshot.
While I haven't tested any buckshot/defensive 410 loads out of a pistol or out of any barrel shorter than 14", I wouldn't discount 410 buckshot loads out of a Mossberg Shockwave or other shotguns. Yes I keep my Mossberg Shockwave and Mossberg 500E loaded with 3" 000 buckshot loads for him defense.
Since this is about handguns, I'll stay on subject. A 410 defensive load will work just fine out of a handgun at close range of 7 yards or less. I would not try to shoot at any target farther out than 10 yards with a handgun loaded with 410 SD rounds. As mentioned, the rifling does effect the shot in a negative way.
On the subject of the Winchester PDX1 shells and the Hornady Critical Defense shells. They might do just fine out of a handgun at close range. From my testing, they don't do well out of a 14" or longer barrel. The Winchester PDX will hold an okay pattern at 15 yards out of my Shockwave. The Hornady Critical Defense was all over the place at 15 yards. Needless to say I was not impressed with the Hornady Critical Defense ammo. If I had to use something other than buckshot, it would be the Winchester PDX rounds.