Ah, the proof marks tell the tale. And what a tale they tell. Great detailed photos.
- The serial number, 12978 is recorded in my books as made in 1878, three years into the Anson and Deeley patent of 1875. This 1878 date can vary by a year or two, WR record search of the record books will give the exact date of completion. For comparison, #12,576 was completed as a pinfire in August 1873, subsequently converted to central fire by unknown. #13,238 was completed in September 1880, it is an Anson and Deeley action best quality gun like yours only 12 gauge.
- The original proofs are for 28 gauge, 1875-1887, no nitro proof in use at this time, so black powder by default.
But this gun has been reproofed for nitro powder, modern ammunition.
- The words NITRO PROOF were initiated in 1896 and were used until 1954.
- NP is the Birmingham nitro proof mark, in use 1904-1954
- The word CHOKE was used 1887-1954
- 2 1/2” was only used 1925-1989
Summary, this gun went through a second proof, for Nitro Powder sometime between 1925 and 1954. This means that at that time this gun was proofed safe to use with modern smokeless 2 1/2” ammo. Unfortunately in the absence of a date code stamp this is as close as I can pin it. If this was initiated by Westley Richards it may show in their records and you’ll get a copy.
This is a very nice, very unusual ( not unusual for WR who made an almost infinite variety of firearms) gun that if well kept since reproof is perfectly usable with modern 28 gauge 2 1/2” ammo - if you can find some. Please update when you get your package from Westley Richards. J.