Using OpenIV open 
GTAV/update/x64/dlcpacks/patchday3ng/dlc.rpf/x64/models/cdimages/weapons.rpf
drag and drop them into this folder and delete w_pi_pistol+hi.ytd

if you are using the latest version of gta 5 put files go to patchday8ng instead of patchday3ng

enjoy