That is how Remington made ribs, both solid and ventilated, until the Model 11-48 and the Model 870 came out. For some reason, Remington began offering a vent rib on the Remington Autoloading Gun/Model No. 11 in the 1910 catalogue, but I don't find a vent rib offered on the Remington Repeating Gun/Model No. 10 until the 1923 catalogue, and then only on the No. 10T "Target" Grade?!? The No. 17 seems to have been offered with a plain barrel, a matted barrel or a solid rib barrel, but not with a vent rib.