Remington Arms Co. used the terms "Flat Matted Rib" and "Hollow Rib" to describe the ribs on their Remington Hammerless Doubles up through the 1905-1906 catalogue. Early on, all the Remington Hammerless Doubles had the Flat Fatted Rib. In the 1902 Remington Arms Co. catalogue they begin offering "Hollow rib furnished to order" on the C-Grade and higher guns. Beginning with the first 1906 Remington Arms Co. catalogue they just say "matted rib" for the various K-grades and "concave rib, matted" for all the grades from A- to EEO-grade.
Hollow (Concave) Matted Rib left (1905 vintage CEO-Grade), Flat Matted Rib right (1895 vintage BE-Grade).
