Since I am up way past bedtime, and sure Rob is getting is beauty sleep, I will just give my opinion and you can find it MB downrange radio # I don't know which. To me, it is the recoil impulse, the time it gets the slide to function, return to battery and get back on target, it is not the force of the recoil, just this abnormal waiting for things to happen vs a 9mm or .45, now this is full house defense ammo, not custom tailored for competition, I still have one, a Kahr M40, the grips a so small you get complete control of the pistol, it is heavy, and it shoots so accurately I just want to keep it. I shot head to head with a G27, and I outshot it, except for the additional 4 rds the 27 had, remember, more rounds, the longer you can fight.
I dislike my Benelli M1 super 90 for the same reason, the recoil impulse is very weird to me, technically it may be faster, but my 1187 Remington I can start from the ready and clear 5 plates in 1.8 seconds all day long. The Benelli makes a fine hunting shotgun though. Maybe my 1st choice for Turkey and of going after hogs in thick brush. Trusty over and under, is 1st choice for birds.