I've got an old Heritage Rough Rider in 22lr that my grandfather baught a few years ago and while looking it over I found that it doesnt always catch on the half cock and let me spin the cylinder to eject the rounds in the cylinder. I'm not entirely too familiar with single-action revolvers but this one seems to be a bit odd in more than one way (including the fact it has a manual safety). I cant get the hammer to catch on the half cock or full cock if its pointed upward any. I'm guessing that's not normal, I have a feeling I'm missing a spring or something because its like gravity has to let the trigger fall to be able tto catch onto the half cock and full cock. Any suggestions on what to do to fix the problem, if it even is a problem?