I am not in possession of an Edgun I could tell you to the exact size, but you can save the image and increase them until the scope tube has measured 30 mm to the monitor (sniper SWFA SS 10×42 believe it is) then you can make the shot size which you need. I so I made my bullpup.
I think your size is 110 mm.
I hope I made myself clear, if not: http://imageshack.us/a/img138/3448/ujjd.jpg http://imageshack.us/a/img547/6221/5m61.jpg
Thank you very much bebtm ..To help,
Regards