nice pistol. no hidden proof marks underneath the barrel?
william iv was also king of hanover at the same time he was king in the UK. royalty was pretty much interrelated back then, and is still. hard for them to find a royal mate of similar age they are not too closely related to.
his successor, victoria, managed to marry most of her children around the royal courts of europe - WW1 was in fact a squabble amoungst close family.
p.s. - what is the crown/B mark on the barrel? interim proof? germany also had a crown/B proof mark. it looks a bit mis-struck, could there have been another letter right of the 'B'?