He blinks when shooting
In his autobiography, Total Recall, Arnold says:
"I worked with guns every day before we filmed, and for the first two weeks of filming I practiced stripping and reassembling them blindfolded until the motions were automatic. I spent endless hours at the shooting range, learning techniques for a whole arsenal of different weapons, getting used to their noise so that I wouldn’t blink. As the Terminator, when you cock or load a gun, you don’t look down any more than Conan would look down to sheath his sword."
Also, earlier in the book:
"I had a very clear vision of the terminator. I told Cameron, “One thing that concerns me is that whoever is playing the terminator, if it’s O. J. Simpson or whoever, it’s very important that he gets trained the right way. Because if you think about it, if this guy is really a machine, he won’t blink when he shoots. When he loads a new magazine into his gun, he won’t have to look because a machine will be doing it, a computer. When he kills, there will be absolutely no expression on the face, not joy, not victory, not anything.” No thinking, no blinking, no thought, just action."
However:
- he blinks multiple times when shooting Ginger crawling on the floor
- I believe he looks at the Uzi when reloading in Tech Noir just as he's about to shoot Sarah on the floor, although I can't tell for sure