personnel. During the Vietnam War, kills had to be confirmed by an acting third party, who had to be an officer, besides the sniper's spotter. Snipers often did not have an acting third party present, making confirmation difficult, especially if the target was behind enemy lines, as was usually the case.
Hathcock himself estimated that he had killed 300 or more enemy personnel during his time in Vietnam.
"Charles Benjamin "Chuck" Mawhinney (born 1949) is an Oregon-born American who served in the United States Marine Corps as a sniper during the Vietnam War. He holds the record for the most confirmed kills by a USMC sniper, having recorded 103 confirmed kills and 216 "probable kills" in his 16 months of action."
"Adelbert F. "Bert" Waldron III, (March 14, 1933 October 18, 1995) was a United States Army sniper who served during the Vietnam War with the 9th Infantry Division. Although little known, until 2011 Waldron held the record for confirmed kills by any American sniper in history at 109. Although U.S. Navy SEAL Chris Kyle later acquired more confirmed kills, Waldron worked in a jungle environment where target opportunities were less commonplace, whereas Kyle worked in a target-rich urban environment where the rules of engagement were more lax."