1. Chris Kyle was in the Army, he didn't have the luxury of choosing a rifle. He used what they gave him.
Negative, he was a Navy SEAL. He got to choose from a variety of SWS and he chose according to the mission that he was going on. He used a .308 up to a .50 BMG and everything in between. His longest confirmed kill was made with a .338 Lapua at over 2,000 yards.
He did not used what was given to him, he used what he asked for.