zakattack467's_m4a1.zip

This download looks like an addon. You need to extract the downloaded zip and put the addon folder in your Garry's Mod addons folder. You should end up with a directory structure similar to below:

• steamapps
  • common
    • garrysmod
      • garrysmod
        • addons
          • zakattack467's M4A1 <-- Addon folder!
            • e.g.
            • lua
            • maps
            • materials
            • models
            • etc

• zakattack467's M4A1/
  • info.txt
  • lua/
    • autorun/
      • server/
        • m4a1textures.lua
    • effects/
      • effect_hit/
        • init.lua
      • rg_muzzle_highcal/
        • init.lua
      • rg_muzzle_rifle/
        • init.lua
      • rg_muzzle_silenced/
        • init.lua
      • rg_shelleject/
        • init.lua
      • rg_shelleject_rifle/
        • init.lua
    • entities
    • weapons/
      • important lua/
        • shared.lua
      • weapon_real_base_reddot/
        • cl_init.lua
        • shared.lua
      • weapon_real_base_rifle/
        • shared.lua
      • m4a1stuff/
        • shared.lua
  • materials/
    • scope/
      • scope_normal.vmt
      • scope_normal.vtf
      • scope_reddot.vmt
      • scope_reddot.vtf
    • vgui/
      • entities/
        • modelofm4a1.vmt
        • vtfofm4a1.vtf

フタオ{HU TAO}♡, zacharygamex, дима копылов, sukoisu47, Jurisdiction, Dunkelheit, Sistine, Front.Face<AFP>ARMY.