I bought this $12 adaptor from amazon because I needed to figure out how to mount a camera to a scope. The scope I wanted to use immediately was my son’s microscope, but additionally I wanted to be able to put it on a bb gun as well as his .22lr cricket.
I doubt this cheap adaptor will work on anything larger than .22lr, but in all honesty I have not tried it.
The adaptor was too large to fit on my son’s microscope without adaptation, and instead of doing anything permenant, I simply took painter’s tape (so as not to leave residue or be hard to remove.) and wrapped it carefully around the objective tube to increase its diameter.
I went slow so I could keep the tape in the same area so I had a smooth top and no wrinkles.
It was not hard, and did not take long but it was tedious.
The do make commercial adaptors and lenses specially for microscopes, but they cost several hundred dollars and are for specific cameras and microscopes.
I wanted something universal and cheap so I had to be okay with a less elegant solution.
Once I had figured out how to put this on his scope, I went back to the safe to try it on his rifle.
There are three different adjustments, and none are very fine, so it takes a minute to get everything lined up and the screws tightened.
Actually, the installation part is a true PITA, Getting the reticle level and lined up on the scope to reduce parallax and allow the bolt to be thrown takes patience.
It also disallows the use of the actual scope when completed, but this setup allows me to watch over his shoulder and see what he sees. With the phone set to video, it also can be used to go back and look at trigger control and follow through.
For the price I am pretty satisfied with the setup, and if he gets into using it I may buy a better setup – something specific to his rifle scope.