I've got one of these and it works great:

http://www.crosman.com/site/listing/1101



Shoots a .22 caliber pellet at ~450 fps, but it is hand pumped so you don't need co2 cartridges. They're built better than the regular crosman guns too. It won't break the bank either at about $125. Whereas the TDR is over $1000.

A rifle would definately be better, but they are much larger and heavier.