It is easy to store semi-auto pistols in a gun safe using traditional racks that store the gun in the muzzle-up position. However, these racks do not work very well for revolvers since the measurement between the top of the back-strap and the bottom of the grip varies greatly on different revolvers. Several factors come into play such
as the frame size, square grip or round grip, extended grips, etc. You can find the solution to this problem at your local Home Depot or Lowes. Buy a sheet of 1/4"sheet of pegboard, 1/4" dowel rod, and two "L" brackets. Cut the pegboard to fit the height and length of the safe shelf you are going to use for the revolver rack. Then bolt one"L" bracket on each side of the pegboard to hold it up and against the back of the safe wall. This is only necessary until you get one or two pistols/revolvers on the rack, so you can omit the "L" brackets if you prefer.
Cut a length of 1/4" dowel rod for each pistol/revolver you want to put on the rack. The length will be determined by the length of the revolver's barrel. I cut the dowel 1" shorter than the barrel, except 2" revolvers get a 1 1/2" dowel rod. Push the 1/4" dowel rod into the appropriate hole in the pegboard to match the height of the barrel. You can use the same square footage twice by storing shorter pistols/revolvers under taller ones with longer barrels.
It's quick, easy, flexible and cheap.