ESB DL-44 scope mount suggestions

Hi all,

I've just finished my ESB Han Solo blaster build and it looks great, but although the scope mount knob is screwed as tight as possible, after a considerable amount of handing I've noticed the scope mount will ever so slightly move. I'd consider it the weight of the M-19 scope doing this. It is quite heavy. My question is, what are some of your suggestions for permanently restricting the movement of the scope mount for good?
Unless you're doing the Hoth version (mine's the 'standard' Bespin version), it's essentially only held in place on the gun with a single thread. Thoughts?

Thanks.

It would be easier to help with some pics of the used parts.

Generally i would suggest to drill and tap a additional sunken tiny extra screw under the mounting knob, that would help to avoid the mount from spinning.