Reducing recoil with a barrel? Really? If that's the case then Beretta ought to tell Ferrari the secret so they could re-profile their V10's combustion cylinders. Less vibration would prolly make things a whole lot easier where margins are measured in nano seconds.
I'm not arguing their case, but by having a larger bore, for most of the barrel length WILL reduce the acceleration of the shot charge etc, as gasses will seep past. As I said, this will result in reduced velocity thereby reducing the recoil over all and will also lengthen the initial pulse, which is where the perceived reduction comes from. To be fair, it is probably minimal in reality and more placebo than actual felt reduction.
As you are clearly familiar with Newtonian physics, I would expect that to be apparent to you.
I can't comment greatly on the Ferrari V10, but I doubt they want loose fitting pistons as this would also result in a loss of power and probably increased vibrations!
Something else to consider (not directed at anyone)...is that the recoil pulse, isn't one pulse, it is several because several things are happening, during the shot.
So possibly being able to feel the difference between choke constrictions, is certainly plausible...much of the shot is running into a wall at high speed...it is the same effect as the forcing cones have, at the other end. So the energy dispersed during constriction...has to go somewhere and not all of it will be in constricting the shot column.
We should not doubt the intricacies of our own bodies and how sensitive they may be.
So apart from all that jazz...how damn sexy is that DT11 though? Gotta love the styling!