To install with OpenIV you replace the provided w_sr_heavysniper and w_sr_heavysniper mag files in these two places: 

GtaV\mods\update\x64\dlcpacks\patchday8ng\dlc.rpf\x64\models\cdimages\weapons.rpf
GtaV\mods\x64e.rpf\models\cdimages\weapons.rpf



The provided w_at_scope_max files in these two places:

GtaV\mods\x64e.rpf\models\cdimages\weapons.rpf
GtaV\mods\update\x64\dlcpacks\patchday8ng\dlc.rpf\x64\models\cdimages\weapons.rpf



And the weapons.meta goes here:
GtaV\mods\update\update.rpf\common\data\ai\weapons.meta
(The meta titled sniper only is for people with premodified weapons.meta files to copy.)



If you have any problems with the gun not showing then replace the gun and attachement files in the other patch days.  


Don't forget the gun model has its own scope but will still spawn with a vanilla scope on it. 
Equip the optional scope (which is invisible) in Ammunation or with a trainer to make the gun look correct.



Thanks for downloading.