I built and offline terrain for you to practice this and all gunnery in the game.
1. - Logon online and go to the "Free" tab.
2. - Click create arena and choose "gunnery".
3. - Make no other changes and click OK.
4. - The terrain will be downloaded to your PC while an arena is created on the HOST.
5. - Once in the arena online, go into the CM tools in the clipboard and click on shut down the arena.
Now you have the terrain file but you need to go to the following link for the offline files and instructions to achieve your wirble goal.
http://bbs.hitechcreations.com/smf/index.php/topic,381847.0.htmlFollow the directions and get the zip file with the needed offline files. When you have set it up, choose the gunnery terrain and do offline mode using it. In the tower go into the hanger and select your wirbel and spawn NW. The drones will fly just above your head about 800 yds and you can turn on the LCD gunsight. You will start noticing how the wirble gunsight range marks work as you slaughter the drones.