I do not know anybody interested in vintage shotshells here. I know that in USA almost everthing are "collectable"; we have a border between us, so there is no practical (or even legal) way to send those old paper shotshells to you.
My question is regard any possible danger (rising pressure) in making the change of buck pellets for #9 shot. Please comment.
Now about Destry question about live pigeon, yes of course!!!
About 1 hr drive from downtown Mexico city there is the "Buenavista shoting club" the most famous place for live pigeon shooting in Mexico. All the diferent types of pigeon shooting (colombaire, jaula europea, Barnabie) are practiced in that place.
Also there are 3 or 4 more shoting places that makes live pigeon tournaments within an hour from Mexico city.
Completly legal and still a lot of shoters like it because there are money prices involved in all tournaments.
Best,
Jose