A very lovely paradox you have there. Holloway made strong and well finished guns and your looks to be in very good condition. Beginning in 1921 the Birmingham proof house began to stamp "private view marks" on the barrel flats of most guns that they proofed and I assume rifles as well. These viewers marks were actually coded stamps that indicated the year the gun/rifle was proofed. The viewer marks for 1924 were crossed swords or sceptres with a capital letter "C" and for 1925 a capital letter "D". Actually the letter C is for 1July1923 to 30June1924 and the letter D is for 1July1924 to 30June1925. Letter A through Letter V were for years 1921 through 1941.

According to Nigel Brown in his book: "British Gunmakers" vol II, George & Sidney Holloway's records reside with Christopher Holloway at 5 Noble Avenue, Oldland Common, Bristol BS15 5YY, Telephone 01179 326713. From these record book Nigel Brown produced a chart of serial number ranges and the approximate year dates of production of the serial numbers. Brown indicates that for the year 1923 serial numbers in the 12800-13000 range were used; for year 1924 number in range of 13100-13400 were used and for the year 1924 the numbers range 13500-13600.

G&S Holloway made a lot of guns for the trade and I have one of their 20 gauge shotguns made for Thomas Henshaw, Dublin, which is identified as a G&S Holloway by the "H" preceding a serial number on the short rib between the barrel lumps and the fore end loop; and the cut away action standing breech.

G&S Holloway also favored the "cut away" style of action standing breech (that your gun has) in lieu of the other more common style of "ball" and "ball and bead". This is fortunate as the cut away standing breech has much more metal to support a Greener style cross bolt and heavy loads.

I hope this helps you date your new treasure.

Regards;
Steve Howell