Some say that using moly coated bullets will make the break in process go faster/work better. The break in process focuses on the throat area of the chamber. Regardless of how smooth the bore is, the throat/leade area will have circular tool marks from the chamber reamer. The shoot and clean, shoot and clean regimen is to smooth out these tool marks. The roughness of the throat causes copper fouling. The hot gasses will carry the copper down the length of the bore. Some copper will deposit from friction also. Cleaning between shots removes the fouling from this area allowing the burning gasses to smooth out this roughness. The moly coating cuts down on the tendency for copper to accumulate. In order for the break in to be sucessful, all copper fouling must be removed each time cleaning is done. A better way to break in a barrel is to use the abrasive coated bullet kit. It will do more in less time and increases uniformity the entire length of the bore.