By their very operation revolvers will ALWAYS be more reliable than a semiautomatic, given we are talking about quality firearms on both sides. The ammo in a semi needs to have a good magazine, seated properly, a flawless transfer from the mag to the chamber, fire and propel the bullet, move the slide to reset the trigger and load the next round, eject cleanly despite any issues with the gun itself or the shooters grip and actions and then do that every time you pull the trigger. The ammo in the revolver needs to fire and propel the bullet...and that's it. Only then can we start talking about possible issues with the mechanical parts of the guns themselves...