.457" round balls
A few tins of Remington #10 caps. Remington #10's and #11's appear to be the same diameter with the difference being in the length of the skirt.
A Ted Cash snail capper (Originally designed around Remington #10 caps)
Coupla pounds o' FFF black powder (Ya only gonna git 'bout 175-225 rounds per pound or 30-38 cylinders)
Powder measure, fixed or adjustable, capable of throwing 30-40 grains (volume). I use a FLASK
with a set of fixed measures that screw into it and prefer a load that lets me use a full stroke of the ram so I get even compression on every chamber.
Can o' Crisco & a popsicle stick to shovel it in with or a large syringe with a large gauge plastic needle/tube/hose is a bit neater & cleaner.
No need to pull the cylinder to load, it's quicker & easier to leave it in place, but a loading stand might be handy. (I don't use one myself) In my experience, round balls shoot much better than conicals and conicals are a pain to load anyway. When you seat a ball with no powder under it (It WILL happen!), pull the nipple, push as much powder through the hole as you can, replace the nipple, SEAT THE BALL FIRMLY ON THE POWDER, cap it, and shoot the ball out. No need to get a full charge under the ball, just enough to push it out the barrel, but make sure there is no air space between the charge and ball. Unless you want to take the time to get 30+ grains through the nipple hole, you'll have to seat the ball by tapping it into the chamber with a dowel cuz the ram won't reach far enough. Five to ten grains should be sufficient to propel the ball out the barrel. Clean up is a snap with hot soapy water and a good oiling afterward. Don't forget to pull the nipples now and then and use a good quality breech plug grease when replacing them. Ya don't have to tighten them up like Gonzo at the Uberti factory does with their screws, just snug 'em up good so they'll come out easily the next time.
Caution; ROA's can be addictive.
Four of my fixed sight guns shoot perfectly to point of aim with no regulation of the sights, but I haven't shot the fifth one yet, so it might very well be just as good. I've shot the adj sight pair in Cowboy Action Modern class several times and always kick ass with them.