
Oh Knarley One

Hindsight is such a gift. First and foremost, there is nothing wrong with Brass Frame Cap Guns. Tune 'em up and shoot away. Just don't try and "magnumize" them or run 'em with cartridge conversions.
Other than that
In this instance, eBay is your friend. There are several "breakers" who sell the parts and major assemblies of Cap Guns on eBay. May take a week or two to get two, but they will come available.
People ARE hazardous to Yer Health