Depends on what you mean by "powerful", commercial or wildcat cartridge, current or obsolete? Rifle or handgun? Does it have to be of a bigger diameter or just deliver more ft/lbs of energy or do you just want to know about velocity? Rimfire or centerfire?
Other than a toy gun or water gun, the next most powerful one a citizen can have without a permit is a "B.B. gun".
A BB gun would be more powerful
The 17 pound gun was more powerful than the 90mm gun.
Generally, no. The size is the same, but the mass of the projectile is not. And a .22 rifle bullet is propelled by gunpowder, with a much higher muzzle velocity than an air-powered pellet.
Depends on the application. If you mean power, the higher the caliber, the more powerful it is. for example, a .22 caliber rifle is much less powerful than a .50 caliber rifle.
Yes.
can you use any kind of an 22 shell like an long or short shell in an 22 gun
It depends on a couple of factors, but generally speaking, a gun.
First, it is rifle, not riffle. Second, no, or we would shoot tanks with a rifle. Cannon are more powerful. Finally, depends on the rifle. I have a .22 rifle and a .44 magnum pistol. The pistol is far more powerful than the rifle. I also have a .22 pistol, and a 30-06 rifle. The rifle is far more powerful than the pistol (in THAT example).
"Powerful" is a subjective term. The .22 is more powerful than some cartridges, but less powerful than others. A .22 is (generally considered to be) underpowered for self defense, but it has plenty of power for small game hunting.
sniper riffel
the measurements of a round are not measured in that way, nor does the size of the gun have anything to do with how powerful it is