So what is the life expectance of a factory Remington 700 Sendero 7mm RUM barrel? I have around 400 rounds through the factory barrel and thought that it was just getting broken in. It is in being rechambered for a tight neck with minimum freebore. Also having a muzzle brake installed. Question is, should I be having all of this work done to the factory barrel or should I be having a new barrel installed?