I saw an advert a few weeks back (and ordered), a $50 "Endosnake" bore scope (thinking why not?) and received it yesterday. It plugs into a smartphone or tablet, and with an app can capture video or images. So...I ran it down a "shot out" 6.5CM Bartlein I had tossed on the junk shelf (3000+ rds down the tube). Not bad for $50, and you can at least see the throat erosion (plus that weird straight line mark up the breech...have no clue what that is from). At any rate, it's not a true bore scope, but I could see it coming in handy for just seeing in really tight spaces (like through a spark plug hole to view the cylinder walls of an engine, or inside an intake manifold, etc.), and figured I'd pass the finding along... Yeah, this barrel is toast...