The problem with Break Free is that it is a poor lubricant.
It is too thin, and the solvent contained in the formula has a tendancy to dry the lubricant away after a few days or weeks. It also has the tendancy to attract lint, dust, dirt, sand and anything else that happens to be around. When the drying process then takes place this mixture turns into a gooey substance that makes carbon very difficult to remove.
A much better solution is to use a seperate solvent, such as shooters choice, Hoppe's etc(only to bolt or bore, never to the receiver).... followed lightly by a dedicated lubricant, such as Militec-1, etc.... applied to bearing and high wear surfaces. I use a paint brush to apply mine inside the upper receiver and to bolt areas, etc......
This will cut down on the amount of dried carbon that will adhere to surfaces inside the upper receiver and on the bolt, and make cleanup much easier. A rag, toothbrush, q-tips and pipe cleaner is all I ever need outside of the bore(no scaping).
There is no doubt that currently most of the malfunctions attributable to the AR-15 series of rifles are due to improper and inadequate lubrication, rather than inadequate cleaning.
A large part of this problem are the characteristics of CLP's which are a compromise, but in reality do nothing exceptionally well. In my opinion, it can only be considered a poor solvent and an inadequate lubricant.
James
former USMC ('79-84)