You may want to go to the US Optics website. They are the only sole source manufacturer and repair shop for the M40A1 and A3 riflescope.
http://www.usoptics.com/sub_pages/scope ... ecordID=10
I don't think unertl is making the scope anymore but I could be wrong.
http://www.usoptics.com/sub_pages/scope ... ecordID=10
I don't think unertl is making the scope anymore but I could be wrong.