In case you are not aware, revolvers are NOT pistols. A pistol is a handgun that shoots the projectile (bullet) from the barrel, which is how handguns started back in the 15th century, and were all muzzle loaded. While in today's world, we use cartridges and nothing is muzzle loaded, all semi-auto handguns are pistols because the cartridge, and hence the bullet, are all forced up into the barrel from the grip, and they are launched (fired) from there. Whereas, all revolvers load the cartridge into a cylinder that rotates (revolves), and hence the name 'revolver'. This is where the bullet is fired from, and not from the barrel.
If you doubt this, feel free to look it up. And if you look up the definition of pistol, you will often get the 'common' definition meaning any handgun;, but technically this is incorrect, but it there simply because it is misused so often, especially as a result of it being misused in many of the old western movies and TV shows, which was done simply because they did no know any better! They were movie and TV experts, and not gun experts. But almost all ammo and handgun manufacturers list these separately and never combine them or list revolvers or revolver ammo as pistols or pistol ammo. Of course,, there are a few exceptions, such as with Buffalo Bore in some of the ammo ads, and I have contacted Tim, the owner of BB. He well knows what a pistol is, but thinks that the marketing hype is needed for more business to attract more customers when they use the term pistol when it is used in their listing for revolver ammo, so he will not change it.