I just got a neat tool. A NIDAGE 11.5 foot BLUE TOOTH borescope. I got mine used for under $20 off e-bay and have it set up off an I pad. It will also work with a smart phone.
It is semi rigid so you can bend it and have it stay. It rechargeable and you can adjust the resolution to 1920 x 1080. Light turns on and off.
It is long enough that Greg Long can sit at his kitchen table and look down the cylinder of a Series 80 in the barn.