Rcher--thanks for posting these and for sharing your experience. I love borescope videos.
I'm still experimenting with the .22, which seems to be the most critical as far as getting it clean before the accuracy falls off. On the centerfires, I haven't seen much effect as long as there aren't large pieces of material stuck to the bore, especially near the chamber end. Any deposit large enough to remove material from one side of the bullet will affect the accuracy. But my P-10F barrel is so rough looking that one would think it would not be a good shooter, but, in fact, it IS an excellent shooter, I think because the roughness is so uniform and consistent through the length of the barrel.
On the .22, the bore is so small that a tiny bit of hard material left in the leade area will swage the bullet down and then it will not be sealed by the time it reaches the muzzle. This is one place where the JB Bore Paste or Flitz would be useful--as an abrasive to remove what is there, and as a polish to make the surface smoother so it slows the buildup after cleaning. I have some Flitz left over from polishing the P-10 parts several years ago, I may try it on the .22.
"Don't aim your borescope at anything you don't intend to clean."
Joe