RE: Killing a Squirrel : BB or Pellet Gun?
4 grains!??! Never use something that light to hunt with!!!!Plenty of bb guns. Wait, steel bucket or oil drum, or like a soup can? And it's a pellet gun if it shoots pellets.
BTW, mini-coaxial homemade guns can get 1000 fps out of a plastic pellet, at short range that will kill a squirrel.