I bought a used one made in 2010 per Taurus. The revolver is not locking the cylinder all the time. From the parts diagram I am thinking its a fouled/weak cylinder/stop plunger from looking at the diagam. I say this because when it does not lock I can look below the cylinder and see the stop is not all the way up. This happens about 50% of the time. I'd like any suggestions before I take the gun apart.