[mlov420]

gamemode_casual.cfg, and other files similar (gamemode_competitive.cfg, gamemode_deathmatch.cfg, etc.) are default files that come with the game. If you update them, once there is a CS:GO update, those files will get set back to their defaults, meaning your custom settings will get changed back. Also, they are one of the first cfg files that get loaded, so often times other configs will override their settings.

What you want to do is take that gamemode_casual.cfg file, duplicate it, and rename it to gamemode_casual_server.cfg

Once you do that, set all your custom configurations in this new file. When you change from map to map, this will be the last standard config to load and your settings should remain however you've set them. Some maps do have custom settings that will change things, but your gamemode_whatever_server.cfg file *should* override them.

This new file will not get overwritten when CS:GO updates, it will always keep whatever settings you set. You don't need to do anything special for the game to recognize and read this new file, it will automatically do it if you set the name to gamemode_casual_server.cfg and are running the Casual gamemode (game_mode 0, game_type 0 )

Hope this helps!