Hi Folks,
A fellow shooter posted an article a while back on other boards about a barrel relining project he had and in that he mentioned this cheap USB borescope. Being so cheap I figured it was worth the risk so I ordered one. This board wont let me post the Ebay URL where I bought it but you can find that on my site.
It's 20" and has reasonable resolution. It certainly seems worth the money.
There's a more detailed writeup including pics and video clips at my blog site
http://BPCR1885.net/34-borescope/