I was looking at your thread about your rifles lens problems. I have the same problem, though only with my lens, my diode and its window are fine. did you ever get it fixed? I ordered these www.rayfoss.com
I was able to easily remove the lens from its housing, and am confident that I could screw one back in, but the ones i ordered seem to be longer, so I hope they fit in the housing. I emailed max but no response yet. If you fixed your lens and got it somewhere else it would sure help me, if the ones i ordered don't work. If you have not fixed it and these work for me, I will let you know.