Actually of all the abortions constructed to get around the California ban, I think I'd like the pump the best. You can do aimed fire with a pump pretty much as fast as you can a semi-auto, with a little practice. And you don't have to give up the other stuff, like the pistol grip, the flash hider, and even the evil bayonet lug. Clearing jams is easier too.
But maybe I'm prejudiced, since I for a long time the only guns I owned were pump action shotguns. I'd shot .22 semi-auto rifles before then, but I didn't own them as I did the shotguns (from age 14 up to my present advanced age). Of course since the 5.56 doesn't recoil much you don't take as long for the follow up aimed shots, like one does with a 12 gauge, double, pump, or autoloader. (Actually my very first shotgun, which was only borrowed until Christmas when I got the pump, was a bolt action 16 gauge, follow up shots when wing shooting with that beast was a challenge. I didn't get a single bird with it. :) )
Can you describe one?
I thought that a pump-action required a blunt-nosed round so that the rounds could be lined up without a primer being hit by the point of another round. Is there such a "blunt-nosed" .223? How many rounds can such a pump .223 hold?
Since it is not semi-automatic, I presume that it is Kalifornia legal. It's ironic that we have the FFL infringement in Kalifornia to help keep us out of trouble with respect to all the other infringements. It takes a lot of expertise to know what's legal here anymore.