How can "Low Recoil" be the same??

The low recoil 00 Buck we went to was the result of 2 things - there is only 8 pellets instead of 9 so the mass of the projectiles is less. And the velocity is reduced by about 200 fps. The up-side included much tighter groups in addition to the reduced recoil.

that makes sense with the "low recoil" buckshot since the mass is less and velocity is only slightly less, the "momentum" of the load is less. Therefore the reaction is less equalling lower recoil.
But I'm asking about a handgun cartridge which has the same grain weight bullet as a standard round but is labelled "lower recoil". Example is the hydrashok rounds we talked about in another thread here. If the bullet weight doesn't change and the muzzle velocity didn't change, then momentum must have been the same and recoil will be the same.

Help!!

og

OG,

Could it be that the pressure curve is either gentler, giving more of a gradual shove, or much sharper and quick to taper off, so it's not as noticable? Recoil would be the same, and "reduced recoil" would be a misnomer.

Just guessing here.

Josh <><

We need some chrono data to compare and maybe show if there is a difference.