How To Battle Zombie Hordes

From Wired:

It is widely accepted that the best way to stop a zombie is by destroying its brain with a bullet to the head. In practice this is a difficult feat of marksmanship under combat conditions (even the police only manage 25% hits ) so you want to carry as much ammunition as possible. Some readers suggested using the small, lightweight .22LR round, suggesting that this has enough energy not just to penetrate but will "bounce around inside the skull".

...Of course it depends very much on what sort of .22LR ammunition you are using, as there are many varieties in this caliber, ranging from subsonic heavy bullets to smaller "hyper-velocity" rounds and they all have different properties. But it's worth remembering that .22LR had not been adopted as a military cartridge, in spite of the large number of conscripts out there using the 'spray and pray' technique, as it is considered more useful against small animals than humans. That's got to raise questions about its use as a zombie-stopper.