What is a good load for plinking/target shooting? I am not trying to test it's limits.
You asked so here it is. Ruger ROA's are NOT like any other BP pistol. A completely different animal. They were designed for hunting and will shoot 50gr. of BP. They will BARK!
The cylinder is tapered. (Bigger at the end, smaller the further you ram the ball in). Ruger did this to ease the user in case a round won't fire. In that event, pull the nipple, dig the powder out with a toothpick and push the ball out with a dowel. (I use a golf Tee cut square across the pointed end). I also use the other end to seat the Wonder Wads and also to seat the caps after using a capper (DON'T use your thumbnail)! Works perfect.
They like .457 round balls. They do also like Lee designed conical's, however I've NEVER seen a competition won using the Lee's. (In many cases, they are not allowed). For hunting, they're excellent!
28 to 30 gr. of BP is sufficient up to 50yds. However for maximum accuracy, don't just put the powder in and ram the ball home. You are very likely to get "ball creep". Meaning, by the time you take a few shots, the balls in the UN-spent chambers will work their way out towards the barrel (from recoil) and you may not be able to advance the cylinder.
It is imperative to load with the 28gr. (whatever) amount of powder, wonder wad on top of that, then load the rest of the cylinder full of cornmeal. When you ram the balls in, this concoction will compress. Seat the ball just far enough so the cylinder will spin free and none of the balls hit the barrel on their way around.
I use real BP for numerous reasons. Goex is fine, Swiss is even better (3f), but their is compaction differences between the two. Swiss doesn't compact as much as Goex. With real BP, compaction is everything. If you use some other powder, ALWAYS follow the manufacturer's recommendations. For instance, T7 recommends little to no compaction at all. I've also been experimenting with 2f in this pistol. Honestly, there's a bit less peak pressure and seemingly a touch more consistency in throwing the ball to the target. Too early to say for sure, a bit more testing is required.
I did not come up with this formula. It is common knowledge among serious ROA shooters.
Give this a try, let me know how you do and good luck!