Is an Air Pistol that shoots pellets at 425 ft-sec fast enough to hunt small animals such as rabbits or squirrels?

While the velocity you mentioned can be lethal for small animals, air pistols are generally not considered powerful enough for hunting larger animals. Hunting regulations and laws vary in different jurisdictions, so it is important to check local regulations before engaging in any form of hunting.

In general, air pistols are more commonly used for target shooting and recreational purposes due to their lower power output and safety considerations.