Friend John,
Please re-read my statement on flyer loads/ 10ga. lest it be further misconstrued or perhaps I was inept in word choice. The standard 'load' for a 10 was 1 & 1/4oz. of shot and normally 3 & 1/4 DE or 1200 FPS. That load was used in 10's as a flyer load as well as the general all 'round waterfowl load with appropriate sized shot. Most 10's had 2 &7/8" chamberings. Tens were built and used as pigeon guns early on. Gauge was an option, the max load was fixed. 'Trap guns' by def were pretty much ALL pigeon guns prior to 1900 as there simply was not sufficient use of clay targets to justify the term being used in any other context prior to that. Going from memory [a big gamble, that] the ATA Grand American was still live birds until just after the turn of the century.
I may well be mistaken, but want to say that the first 'Trap Gun' in the modern context, meaning expressly built for clay target shooting, was a single bbl gun and perhaps the Baker, but will defer to those more historically bent to answer that. I think the term 'trap gun' and 'pigeon gun' are pretty much interchangable prior to 1900, certainly in the early 80's they would have been. In fact, I would guess that the marking 'Trap Gun' was the made for the American market part of the Greener statigem.
FWIW, I traded off a 10 ga. Bonehill 'Pigeon Gun' so marked w/reversed triggers earlier in the year. I think the term 'pigeon gun' was more a Brit term initially, and over time came to infer a high or higher grade in its connotation in addition to being the first purpose built and marketed competition shotguns.
