I got this one: http://www.cabelas.com/product/Shoo...=SBC;MMcat104792580;cat104701680;cat104257080I bought this for my Remington cylinders. Had to take the plastic inserts out, works great. Not "authentic" I guess, as if anyone carried spare cylinders back in the day.
I've yet to buy a ROA spare cylinder, just too expensive. But, yeah, if it works for the Remmy, it'll work for the ROA, same siize cylinder.
http://www.cabelas.com/product/HKS-...Loader+pouch&WTz_l=Header;Search-All+Products
The ones from Cabelas might require soaking in water to stretch for fit. Just oil the cylinders well and use Saran wrap, insert and let leather dry. This is what I did for my 58 Remmy cylinders, worked fine.Cabella's has spare cylinder pouches for the Remington 1858 Army that match the cowboy holster. They would probably fit the Ruger Army, too.