I have searched the inter webs high and low for an official answer. My thought is likely the 30s is not available in a Gen 4 configuration. I did find several listings, one from Osage County Guns advertising a Gen 4 30s. Anybody seen one in person if they exist? I handled a 30s at my LGS today and really liked it. I happen to prefer the Gen 4 configuration and probably would have bought it on the spot had it been.