What is the next caliber up for a 22 air rifle?

Answer 1

.25 Caliber is the next size up from .22 Caliber

Here are the sizes of pellet calibers.

.177, .20, .22, .25, 9MM (.0357) 45 cal and 50 cal

I believe there are a few .25 cal spring rifles, however most everything above .22 cal are in the world of PCP (Pre Charged Pneumatic) air rifles and require a special hand pump or Scuba tank to charge them to 2.000 to 3.000 PSI. These air rifles are used in professional and Olympic shooting and in medium to large game hunting. The cost of these rifles starts around $350 and goes up beyond $3000. The cost of the charging equipment for these rifles can add another $200 to $400.