How powerful are BB and Pellet guns?

In this video Ill compare the power of several types of air guns, including airsoft, BB, Pellet, and a 22 long-rifle. I compare them by shooting cans of spam, drywall, and other things. For some reason the slow-motion shot of the .22 doesnt seem to play in the youtube version, it just sticks on one frame.\r
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I would also like to comment on the number of folks mentioning my formula is wrong. Yes, I knew it was wrong when I made the video. I was just trying to simplify things for people. I ually used the full formula when calculating the joules shown. I didnt expect people to be using this information for passing math class and I just wanted people to realize that mass was just as important as velocity in determining energy. For those calling for me to edit the video, sorry.. It is impossible to edit a youtube video once it is posted.