Thank you,
@Shootist43 - I literally saw it at 2:55 PM yesterday and by 2:57 I had bought it. I simply knew I had to have it! Unfortunately I don't have any details as to the history of it. I'll ask J.J. (the seller) who the most likely maker is--that will be a great start.
A bit of firearm history about Army and Navy Cooperative Society, Ltd., copied from a post on thedoublegunshop.com:
"The gun department opened in 1873 at 105 Victoria Street. The manager was S. J. F. Newbury who retired in 1909, F. W. Cole replaced him. At some time the Society became a limited company [...] In 1888 the gun department moved to the adjacent building at 8 Howick Place but, probably at this time, it briefly moved to 117 Victoria Street. In 1890 a branch was opened in Bombay by Thomas Lawrence (ex Purdey), followed by a branch in Calcutta (managed from 1901 by Archie Leeson, son of W. R. Leeson of Ashford, Kent, and London, and brother of Reg Leeson of R. B. Rodda of Calcutta). By 1901 other branches in Delhi and Karachi had been opened and agents had been appointed in South Africa (in Cape Town and Durban).
"Although the Society made some of the other products it sold, they never made guns;
guns and rifles were bought mainly from Birmingham, bearing either the Army & Navy name or the manufacturers name. Philip Webley, W. & C. Scott (later Webley & Scott), Westley Richards, Greener, Tranter, Vickers, Mauser, Mannlicher, Colt, Winchester, Smith & Wesson, Marlin, Hopkins & Allen and others
all supplied the company. Not only guns but also ammunition bore Army & Navy names, Reliable, Victoria and A. & N. Nitro amongst them. At some time the company had a shooting ground at Greenford. In 1934 the Society became Army & Navy Stores Ltd., and it opened its doors to the general public."
Given the fact that the barrel flats don't look like they were reproofed, there is a possibility that the rifle was made expressly (heh) for the nitro round. So, if I had to guess, I'd say it was made sometime between 1899 and 1902 (when Jeffery introduced the 3" version) or shortly after. As for the maker, I don't think it's a Westley Richards, since it's a hammer gun, so my guess is that it could be a Webley--but I'm wading into the deep waters of too many assumptions. Either way, it's a fantastic-looking rifle and J.J. tells me it's a really good shooter with tight bores and easy loads that regulate very well in it.
Can't wait to take it to Africa!