I own one of those and it is truly painful. I did at one point load some 45 caliber round ball over trail boss that was not brutally painful. I have all so shot some of my subsonic (in a marlin) 550 grain loads that chronograph about 680 FPS from the derringer. Those are pretty bad. Factory Hornady Leverevolution left me with a bruise on the palm of my hand.
It dose how ever work well with 410 shotshells and they dont kick that bad.
I wish heizer defense would make one in 357 magnum. That should be a no brainer.