I'm not sure that this is what you were asking about but the collar button bullets were made from moulds introduced, I think, in the 1880s by Ideal, the firm that became Lyman. As near as I could ever tell, they looked like a collar button (I have no idea what a collar button looked like). The were cute little things. I think that there are pictures of them in maybe the 1st Ideal Cast Bullet Handbook or their Centennial Journal.
I'm pretty sure RCBS never made these. I'm also pretty sure that Ideal/Lyman hasn't done it in over a century.
Personally for target shooting I prefer SAECO #015. Weights about 300 grains. You don't have to drive this hard to get a very accurate load. Mild recoil. Accurate. Ideal for just punching holes in paper (but probably not anything else).