I have a 642-2 which i bought several months ago. I was shooting some hornady +P ammo in it for the first time ever (this is a .38 special +P rated gun, and this was factory ammo...this gun has never had reloads through it). I loaded 5 rounds and made it through 4. The 5th round wouldnt fire, and I noticed the trigger would not cycle the cylinder when pulled. I unloaded the gun and noticed that now the cylinder with turn freely counter clockwise when locked in the firing position. When I pull the trigger, the cylinder doesnt cycle, although it looks like the firing pin comes forward. Any clue what broke?