Complex sentence: Christopher Scott "Chris" Kyle (April 8,1974--February 2,2013) was a United States Navy SEAL proclaimed to be the most lethal sniper in U.S. military history, having accumulated 160 confirmed kills out of 255 probable kills.
Split into simpler sentences: Christopher Scott "Chris" Kyle (April 8,1974--February 2,2013) was a United States Navy SEAL. The most lethal sniper in U.S. military history, he accumulated 160 confirmed kills out of 255 probable kills.