SxS appropriate for early/mid 1860s?

[Patrick Henry Brown]

We have a member here that wishes to set his impression Circa 1860-66
so he too wants the Pecussion ..( I sent him link to Dixie thank's Rickk )
He wants full 28 barrels as well.
We are an NCOWs posse' and we will allow the Muzzle loader he will have to cap in on the clock
and there will be no reload for percussions needed.

I use a 78 Colt Hammer gun myself ( TTn) but I may just tackle a Percussion my own self  

The flipside of that though is that he only has to shoot two targets and usually, there are no makeups for Pistoleer in NCOWS. So instead of the usual 4 targets with a reload on the clock, he has to only shoot two. That would be the same with cartridge or percussion.

[Sir Charles deMouton-Black]

I spent half the day trying to find some of my lost links.  The one that still eludes me is the obscure page that can date your old Husqvarna.

The point I was researching was the date of introduction of the French Lefaucheux underlever pinfire design. Anyway, Husqvarna manufactured them under licence from 1877.  As soon as "modern" ammunition was available the switch was made.  The Lefauxcheux design was one of the earlier ones available in serious quantities, but I'm not siure how many came to America. Husqvarna made this pattern up to 1956.  81 years!   Plenty of them are available at good prices, and I used one in a cas match last August and it worked well.

When the NWMP marched West in 1873 they had PERCUSSION SxS shotguns for foraging, and the remained in service for quite a while.

The answer;  There were very few break open shotguns available in the West until sometime in the 1870's.