I've been trying to find:
1. When Live Bird and Inanimate Target competitors were limited to 1 1/4 oz. loads and
2. IF 8g guns were prohibited, or excluded because of weight limitations.
Jan., 1879
The Chicago Field reported the New York "Brooklyn Gun Club vs. Philadelphia Gun Club, 8 guns per side competition. "Only two Parker guns on the grounds. Mr. T.E. Broadway of the Brooklyners used a Parker 10 ga. with close choke weighing 9 1/2 lbs shooting 4 1/2 drachms of DuPont's Diamond Grade and
1 1/4 oz of Tatham's soft shot. For the Philly club, Mr. H.A. Burroughs shot a Parker 12 bore with medium choke weighing but 7lb 14oz. He shot 4 drachms of Hazard's Electric Powder and
1 1/4 oz of chilled #7 in the left barrel and #8 in the right. UMC's new paper shells were said to be the choice of most to carry their loads. W&C Scott was the choice for most shooters with a pair of Remingtons and a Moore and a Williams & Powell."
I couldn't find a shot or gun weight limitation for the first "International Clay Pigeon Tournament" (or inanimate target tournament) run by Geo. Ligowsky's and J. E. Blume's National Shooting Association in Chicago in 1884; the second International Tournament was in New Orleans in 1885.
Sporting Life reported the weight limitation of 8# in 1898
http://www.la84foundation.org/SportsLibrary/SportingLife/1898/VOL_30_NO_24/SL3024020.pdfJohn L. Lequin. secretary of the Interstate Association, writes us under date of Feb. 25 1898 as follows:
"We have received inquiries from most all directions recently from a number of shooters who are probably desirous of entering the Grand American Handicap next month, concerning the weight of guns, and whether the handhold and recoil pad will be counted as a part of the gun when weighed. The subject has been placed before the Tournament Committee of the association, which committee has decided that the guns will be weighed naked."
As Bro. Tom said, the "rest of the story" is likely to be quite interesting! Possibly ordered in 1896 and put in the closet when the weight limitation was established in 1898? Of course private flyer shoots continued thereafter.