HalfaDouble,
My own 8x57R/360 is a top lever hammerless and is even lighter and handier than my favorite which is an 8x57IRS( both 16 ga 2 3/4", but the smaller one was rechambered from 65mm and reproofed at Ulm in 1969). Drillings for 8x58R S&S, 8x57R/360, 8.15x46R, etc, were usually made on a smaller frame than used for the M88 and M93 base cartridges. There is really a noticeable difference between these and 12 ga's.
Mike