So when you first buy a, lets say Colt AR or maybe even a Bolt gun ( Bolt gunners can chime in too). How do velocities change over the life of a barrel. So as the journey goes from brand new barrel to being completely shot out, how do velocities change over time.

We shot a bunch of 14.5's today and there were no real surprises but it made me wonder. So anyone in the know, help a brother out.

PB