The mod replaces the special carbine in the game with the ACW-R.
Installing Upload files to path Grand Theft Auto VModsupdatex64dlcpackspatchday8ngdlc.rpfx64modelscdimagesweapons.rpf In my case Grand Theft Auto Vupdatex64dlcpackspatchday3ngdlc.rpfx64modelscdimagesweapons.rpf