The reason that the Early Single-Sixes went through the 3 different changes from "Long Throw", "Short Throw", and last the "Straight Slot" ejector rod housing was because Ruger copied the offset ejector rod housing from Colt. They started using the Short Throw first as that gave them enough throw to eject the .22 LR empties. Once the .357 Flattop came on the market they found it was hard to eject the empties so they lengthen the throw. Then when the .44 Mag. came out, Ruger had the same problem ejecting the empties so they just got rid of the offset altogether.