Need suggestions on how to photograph rifle bores

This is the one we have.

Digital Inspection Camera with Recorder

They also have this one.

Wireless Inspection Camera - Great Deals on Wireless Inspection Cameras at Harbor Freight

20% with cupon at local HF.

Neither of them will help, although a good enough pixelation, the head is too large at 8.5mm.
You need a head under or about 2.5mm to ensure you can access .22cal barrels.
The problem then becomes the ability of the camera to do what you want, as they have inbuilt LED's also, there's not much room for a good camera, specially as you require it to look sideways at least 45 degrees.
If you wish to utilise this style unit, checkout the HongKong/Chinese market, they provide them this small, you may also find what you are looking for in optical fibre.........ain't technology grand.