You have me there. I'll take a look the next time I have them out.
I know at one point I tried rotating the cylinder to line up the empty chamber with the barrel before closing the gate, but too often I did not time it right, causing it to miss locking up at the desired point.
I know that the "drill" for Colt style single actions is to pull the hammer to full cock before lowering on the empty chamber. If you let the hammer down from half cock it causes the bolt to drag on the cylinder.