Had a somewhat sobering experience the other day......Had a look down a borescope at my lovingly cleaned and carefully fired .243 barrel
Its a Blaser match...fired 1200 from new....mostly home loads, RL19, H380, RL22, Superformance...nothing too "hot"......shoots sub moa with 85 grain Gamekings.
What I saw made my blood run cold.....fire cracking, throat erosion, non existent lands, copper fouling, carbon streaks.......scary! The .243 has always been labelled as "Over bored" but never a throat burner in the same way as a 6.5-.284 but something is sure munching away at the ironwork!
Does it affect how it shoots? Well, so far ....no! But if I was shown the mess the 1st couple of centimetres are in if I was buying it,,,,I'd be running for the door!!
Sometimes its just better not to know!
Also looked down my .22-250....bad but not as bad as the .243 and a 6.5 x55.....hardly a blemish.
So...whatever you do....Do...Not...Look...Down the bore!!!