Thats crazy man, yes factory ports are worthless but a aftermarket port job can decrease muzzle jump 100 percent. I have seen high cal. rifles and shotguns be decreased by alot, some down to the recoil of a .22.
There is somewhat of a major difference in the pressure between a shotgun and rifles. A heavy shotgun is not affected by the muzzle porting.
With all due respect to my friend Jim, the ONLY company that ports target guns is Browning.
Beretta, Cesar Guerini, Blaser, Zoli, Perazzi, Kreighoff, Kolar, Fabbri, Bertuzzi, and many others do NOT port barrels as a standard feature - yet these are the heavy favorites in the serious target arena. Field guns are not ported- if ever there was a need for the magic of porting, it would seem to be on a lighter field gun that uses heavier loads and needs to react in any direction as the birds juke about - yet field guns, even Brownings, are not ported
Sorry guys, port your S&W 500 handgun, or your 50BMG bolt gun.........it simply isn't necessary or useful on a shotgun