22 long is a type of 22 rimfire. Others are CB, short, long rifle and a few others .
22 is a rimfire, 222 is a centerfire.
If you're talking about the difference between a .22 short or long rifle and a .25 ACP, the .22 is a rimfire cartridge and the .25 is a centerfire. Also, the .25 is .03 of an inch larger in diamter.
Mainly length and energy. From the shortest (and weakest) to the longest (and most powerful) .22 BB cap, .22 CB cap, .22 Short, .22 Long, .22 Long Rifle. There are also obsolete .22 cartridges no longer made- .22 Winchester Auto, .22 Special, and .22 Extra Long. The .22 Winchester Rimfire (WRF) and .22 Winchester Magnum Rimfire (WRF) are larger in diameter than the other .22s, and will NOT interchange with them. There are also centerfire cartridges with 22 in the name, such as .220 Swift, 22 PC, 22-250, but they have no relation to the other 22s.
The .22 Long Rifle is a rimfire, whereas the .223 Remington is a centerfire cartridge. The .223 uses a longer 'spitzer' projectile vs. the rounded projectile of the .22 LR. The .223 tends to be a heavier projectile, and has a much higher velocity than the .22 LR.
22 Short, 22 Long, or 22 Long Rifle rimfire interchangeably.
.22 Long Rifle is a longer cartridge.
There are 22 caliber centerfire cartridges such as the .22 Hornet and others, but ordinary 22 cartridges (short, long, long rifle) are rimfire.
Rimfire cartridges do not have a primer at the center of the base of the cartridge- the firing pin strikes the RIM of the cartridge. The most common rimfires are 22 short, 22 Long Rifle, 22 Magnum and .17 HMR.
There is a .22 WRF, and a .22 WMR. WRF is Winchester Rimfire. Bigger than a ,22 Long Rifle, but shorter than a .22 WMR- Winchester Magnum Rimfire. If someone is using the term .22 MRF, it is an inaccurate term.
Only if it's a .22 Long Rifle revolver. It's not compatible with the .22 Winchester Magnum Rimfire.
.22 short, long, or long rifle rimfire ammunition only.
"Regular .22 rimfire ammo IS .22 LR.