Many air rifles claim to hit velocities past the sound barrier (1080 feet per second). I want to know if that is true and if so, what does it take to do it.

Since nearly every .177 break barrel claims to be over 1100fps, I chose the cheapest I could find: A Crosman F4. I imagine any Crosman nitro piston will perform the same so long as it is single shot (multishots have a restricted port and don't shoot as fast). I found that opening the pellet skirt helped increase the velocity, but decreased the accuracy significantly.

The .22 is the Gamo Swarm magnum and it is a real pain to cock. Your arms will get sore cocking this one unless you are unusually strong.