I looked all over to find a clear picture of what I was looking for and could not find it, but I did modify a pic to show you what I mean.
What you are experiancing is called the "Flash" of the gun. Technicaly a non part of the gun. The space between the cylinder and the forcing cone. Should be about 3 thousand of an inch, (roughly the thickness of a sheet of paper)
I highlited the area I am speaking of here. This is where your bullet has to pass between the chamber of the cylinder into the barrel. The first part of the canon called the forcing cone. The forcing cone is made to round off the lead or other metal going through it and prepare it to go into the groves of the rifling. When the bullet passes through there, a very small amout of lead or coper is shaved off the projectile to make sure it fits in the rifling, then the rest is pressured down to a size acceptable to pass in the rest of the barrel. The lead shaved off along with quite a bit of gases comes out of the "Flash".
If you shoot in the dark some day, you will see that the fire ball coming out the front is no where as impressive as the one coming out the sides.
If you place cardboards on either side of the revolver when you shoot it, you will see the cuts in the cardboard where lead and gas hit. After a while of shooting, if you look at the top strap, you will actually see a cut there from the metals and gas hitting there constantly.
Good practice in shooting is not to place your fingers or any part of your hand in front of the trigger.