barrel wear

[marxman]

people talk about failing accuracy as a barrel wears. the velocity must go down too with powder blowing around the bullet. or does it? is it significant? is a rifle performing pretty close to the same velocity wise up till the accuracy becomes unacceptable?

[260 Rem]

I think the "barrel wear" you are referring to is "erosion" that starts immediately forward of the chamber ... the result of hot gases. As I understand the phenomenon, it generally does not extend very far down the bore. I have a buddy that uses HV contours which have a long shank .... so he can set the chamber forward when the throat washes out. I don't think "bullet induced friction" causes much wear. I'm sure the gunsmiths and folks with good bore scopes will explain what is going on...
It makes sense, that velocity would decrease, given the prospect that the volume in the boiler room has increased?