Scopes in Gmod

When I play Gmod, my scopes don’t work. For example, SB Spy’s tactical weapons pack. When I go into the scope, all I get is a purple and black checkerboard pattern. This might not have anything to do with it, but I don’t have Counter-Strike Source. What can I do to fix this?

reinstall the addon.

You might not have a game that the addon requires.

That game tends to be Counter Strike: Source. There was a method to change the scope texture to the combine binocular one, but I forgot what line in the script needs changing.

Okay, thanks, I’ll look that up.