Things start to get a little hazy around the top end of things. The largest SPORTING rifle caliber may be the .700 Nitro Express, although there was an anti tank rifle that was 20 mm (about .80 caliber) and at least one designed in 30mm (1.20 caliber). Years ago, a gun known as the Paradox (part of the barrel was smoothbore, part was rifled) was measured in Gauges rather than caliber- and they were extremely big. I have seen one custom rifle built as an experiment that was a a TWO gauge black powder rifle- fired a lead ball the size of a billiard ball. However, bigger is not always better. Good question, though.
.17 to 20x110 Hispano
The .950 JDJ is the biggest rifle The biggest hand held gun is the 600 Nitro Express Pistol
a .22 caliber
If you are asking about the 2200 Crosman Magnum air rifle then it shoots a .22 caliber pellet not a BB.
A .177 caliber air rifle has very little recoil.
.223 caliber or 5.56mm.
No You could build a rifle in .306" or any other caliber but you are likely referring to 30.06. A 30.06 rifle is referred to as "30 Caliber" but to be accurate it is nominally .308"
Yes, I can. A Barrett M107 is a .50 caliber sniper rifle.
The Dragunov (note corrected spelling) sniper rifle is in caliber 7.62x54mmR. This is the same caliber at the Moisin-Nagant 91/30 rifle.
50 caliber
There has been a revolver made in caliber .600 Nitro Express. This was an elephant rifle cartridge. As a firearm, it is a curiosity, and not a practical shooting firearm. There are also unconfirmed reports of a Maadi bolt action pistol in caliber .50 BMG.
value of a model 49 ithaca 22 caliber rifle