I picked up an endoscope on ebay for $17 shipped from Hong Kong. Diameter 7mm, it plugs into a USB port, has its own light and came with software that enables video and still photos. The field of view is 60 degrees, so it obviously can't focus on small flaws like the borescopes that cost 50X as much. But it can verify if there's rust, lead, or copper fouling. The captures don't show the detail that you can see "live".
Examples:
I was able to verify that the bore on my newly acquired Safari Arms Hawken .50 is super shiny:
http://s1093.photobucket.com/user/nilsek/media/Metmans%20diverse/20130411230314_zps2e4a574c.jpg.html?sort=3&o=2
The bore on my Swedish RB m867-89 still has some lead stuck here and there:
http://s1093.photobucket.com/user/nilsek/media/Metmans%20diverse/20130411230924_zps38b20866.jpg.html?sort=3&o=0
Examples:
I was able to verify that the bore on my newly acquired Safari Arms Hawken .50 is super shiny:
http://s1093.photobucket.com/user/nilsek/media/Metmans%20diverse/20130411230314_zps2e4a574c.jpg.html?sort=3&o=2
The bore on my Swedish RB m867-89 still has some lead stuck here and there:
http://s1093.photobucket.com/user/nilsek/media/Metmans%20diverse/20130411230924_zps38b20866.jpg.html?sort=3&o=0


















































