A mechanic friend of mine has one of these. This thing will let you watch live, take pictures, and record video. The head that came with it is 8mm. He has been using it to check the barrels of 45/70's and larger caliber rifles. Now he has the 5.5mm head ordered. (30.06, .308, etc. oh yeah). You can see fouling unbelievably well. You can also check out the quality of the rifling, throat erosion, etc. It's really neat. Check it out:
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=81957&group_ID=21604&store=snapon-store&dir=catalog
http://buy1.snapon.com/catalog/item.asp?P65=&tool=all&item_ID=81957&group_ID=21604&store=snapon-store&dir=catalog