I'm sure many have already tried this or seen the "You Tube" videos concerning the use of an endoscope for reloading purposes.
You can purchase an endoscope online from $12 to $35 dollars on up. I would recommend buying a high definition (HD) camera!
It attaches to a smart phone/pad.
The software that came with my Non-HD camera didn't work with my Motorola pad so I had to find and download compatible software.
Since I'm pack-rat by nature... I happened to find two different sized plastic sleeves that I glued together to act as the housing for the endoscope camera.
I placed electrical tape around the smaller end so that it would fit in the center hole of my Dillon reloading head.
Attach the camera cable to your smart phone/pad.
Turn on your smart phone/pad and now you have another way to visually monitor the progress of your progressive press.
The camera also provides additional light.