This morning I tried to shoot my pre-24 Model 1950 44 special target. When in double action, the firing pin hits the side of the case. In single action, when I pull the hammer back the cylinder spins at bit too much and does not seem to lock up. I can physically turn the cylinder to lock it and then fire. What could be the problem? Maybe I should take the sideplate off and give it a good cleaning? Any help would be appreciated.