I have a similar rifle to MotelAlpha
A Hollis & son Boxlock ejecter
serial number 30204 their last entry was 30374 in 1919
it has 3" chambers
birmingham proofed
nitro proofed
marked Cordite 750 max bullet
also marked S&B (shot & bullet ) this stamp is not seen that often
the triggers are turnd out to suit a right handed shooter.
Prince of Wales grip

Sherman Bell wrote a good article about a rifle similar to mine and MotelAlpha's in the double gun journal 2001 vol 12 issue 2

The rifling in mine is invisable ,it need a lot of powder residue and bullet lube to see the seven lands and groves ( probably not the correct terminology )

I think the rifling in MotelAlpha's rifle is Metford rifling

good shooting

sbs470