Please excuse my poor memory 8^)
If I remember correctly, at AR15.com or maybe at Bushmaster's site I read something about having to fire 100 - 150 rounds with no cleaning or perhaps minimal cleaning. The article said something about leaving some residue in the barrel to help polish/smooth the barrel's internal finish. To clean the barrel before completing this break in procedure would put you back at square one. This pertained to an AR15 with a chrome lined barrel.
From what you are saying... I take it the break-in will only be a waste of ammo. Am I understanding you correctly?