I like my ported guns, however there are some disadvantages -- like plastic build-up in the vents.Zippy hates ported guns...
Have you ever shot a ported gun in dim light? I've seen significant fire jets from my ports. The additional flash, when shooting in low light, is another disadvantage of ported guns.The point is that the shotguns use fast burning powder so ignition is complete before the shot string passes the ports .There is little hot gas exiting the ports .Therefore no reduction in recoil.
You can't have it both ways, my friend. If the physics reduce muzzle hop, then there's been energy diverted away from the muzzle, that diverted energy will also result in less recoil.I still say it reduces muzzle jump between the 1st and 2nd bird....and does nothing to reduce recoil.