I can't seem to find this map anywhere online where I have checked am I just dumb and the map is in the game or is there some secret place to find the map. I would like to speedrun the map but can't find.

It appears as "weapons course" in the bottom of the drop menu when you click "play" in the main menu. The gun range is a part of the weapons course. You will get to it if you complete the weapons course, or you can just noclip through the door on your left after spawning if you want to grind gun range.