But, you've heard something about running in a new barrel.
It is usually a good idea to carefully run in the new barrel on your rifle. Whether it is a match grade target barrel or a new factory rifle. In the manufacturing process there will be some machining marks or burrs that the lapping process (if done at all) has not completely removed.
Also in the process of machining the chamber into the barrel there will also be some very small machine edges or burrs left particularly in the throat and leade area. The best way to remove these and prepare the barrel for long life is to go through a process of shooting and cleaning.
Initially there may be substantial fouling from the bullet jacket material. This is not unusual. By adopting a simple procedure like I have listed below here you should be able to have your new barrel prepared for normal use before too long. A little work and patience will usually be rewarded