▁of ▁Carlos ▁H ath cock ▁in ▁the ▁Vietnam ▁War , ▁and ▁the ▁scope ▁used ▁by ▁H ath cock ' s ▁oppon ent ▁did ▁not ▁have ▁the ▁numerous ▁internal ▁optical ▁elements ▁of ▁the ▁scop es ▁tested ), ▁it ▁was ▁found ▁to ▁be ▁pla us ible . ▁H ath cock ▁was ▁mentioned ▁in ▁the ▁NC IS ▁episode ▁" One ▁Sh ot , ▁One ▁Kill ", ▁when ▁a ▁white ▁fe ather ▁was ▁found ▁at ▁two ▁crime ▁scenes ▁where ▁the ▁vict ims ▁were ▁shot ▁and ▁killed ▁by ▁a ▁sni per . ▁The ▁series ▁protagon ist , ▁Special ▁Agent ▁L ero y ▁J eth ro ▁Gib bs , ▁a ▁former ▁Marine ▁sc out ▁sni per , ▁realized ▁the ▁significance ▁of ▁the ▁fe ather ▁as ▁the ▁perpet r ator ' s ▁" call ing ▁card ", ▁referencing ▁H ath cock ' s ▁nick name ▁during ▁the ▁Vietnam ▁War ▁(" White ▁Fe ather ▁S ni per "). ▁He ▁cred its ▁H ath cock ▁with ▁" 3 9 ▁confirmed ▁k ills ", ▁apparently ▁having ▁trans posed ▁the ▁digits ▁of ▁H ath cock ' s ▁actual ▁ 9 3 ▁confirmed ▁k ills . ▁H ath cock ' s ▁du el ▁with ▁Cob ra ▁was ▁mentioned ▁in ▁the ▁History ▁Channel ▁S ni per ▁- ▁Inside ▁The ▁C ros sh airs ▁in ▁ 2 0 1 6 . ▁As ▁in ▁M yth b ust ers , ▁this ▁show ▁also ▁tested ▁the ▁question ▁of ▁whether ▁shooting ▁a ▁sni per ▁through ▁his ▁scope ▁was ▁possible ▁and ▁came ▁to ▁the ▁conclusion ▁that ▁it ▁was ▁highly ▁pla us