shoot it, clean it, use WipeOut with accelerator and JB BorePaste. Use a boreguide so you do not damage the crown and always clean from the receiver if a bolt action. There is no special way to break in a rifle contrary to what is written in the internet. Rifle break in and how to do it is rife with internet B.S. What you are doing is burnishing the machine marks in the throat of the chamber. One last thing, if you are using a copper cleaner like WipeOut or Barnes CR10 you do not want a cleaning rod with any brass fittings because the products mentioned will eat your rod fittings, bore brush, and jag if they are made of copper. I use a one piece stainless ProShot (ordered from Sinclair International out of the States) cleaning rod with a ball bearing handle with nylon bore brushes and steel patch holders and no brass jags. You will know when your machine marks have been properly burnished as your 5 shot groups will usually mysteriously and suddenly, tighten up in a dramatic way. Hope this helps
Cheers & Tighter Groups: Eaglesnester.