I like to do wood working and received a catalog that had an interesting item that might be good for checking bores of pitted barrels. It won't give you the depth, but you should be able to get an idea of what they look like on the monitor.
The camera probe is 1/2" in diameter and 1 meter (39" long)

What are your thoughts?

http://www.rockler.com/product.cfm?page=31274&filter=48135

David