David J. Baker in his book "Heyday of the Shotgun" has a good discussion on pigeon guns and the "Hurlingham rules". "Under the Hurlingham rules, there was an upper limit of 7 1/2 lbs" for a shotgun. This might answer your qestion on "Hurlingham weight". And just, as an add on, pigeon shooting started out as a sport for the upper classes! Just as it is today! It is for people with deep pockets! As overheard between two individuals at a local gun store, the first guy asks the question,
"what does it cost to learn pigeon shooting?" And the other guy answers, "Oh, about $50,000"!
