Get your Movie Dork Hat On

And cue 'Comic Book Guy' from 'The Simpsons'.

I sort of wondered about the scene in 'Terminator Salvation' aka 'Terminator 4' where he shoots a terminator in the head at close range with what is probably a 5.56mm rifle round. And those geeks over at Gizmodo were discussing it. 

The questioned asked here and there is if that could kill a terminator or not, as we've seen them shot with pistol ammo, shotgun ammo (non-slug as far as we can recall) in the movies, and with a .50 BMG in 'Terminator: the Sarah Connor Chronicles' (which did disable the terminator shot with it, but it was an unknown model).

Well, it looks the me the short answer is 'Yes' because it's a movie and they can do what they want.

The longer answer is that in this shot, it's not a T-800 which was the model Arnie plays in all the movies.

Proof: the following is a rotated piece of the scene and a shot of a T-800 model head from T2. You can clearly see there is no CPU hole on the rotated shot, and the front of the skull is different as well as the top plate. 

Terminator 4 model:

T2 Model (T-800):

I rest my case!

The T4 version probably has some soldered in CPU that sucks for gaming and can't be upgraded or overclocked. I'll spend the extra bucks on the T-800 model. It has a better operating system too.