Good Christ, I go away for a weekend and come home to this?
There are a ton of various opinions on barrel break in, most are rather absurd, some plain stupid.
On barrels that are not hand lapped match grade barrels, there may be some merit to some of the more vigorous manners that are proposed.
On a top quality match grade barrel MY PERSONAL BELIEF is that the clean this way, then that way, then do a little dance followed by prayers in all directions and to all the God like entities is rubbish.
MY PERSONAL barrel break in is as follows. 1 clean patch down the bore just to ensure nothing is in the bore followed by shooting the rifle.
Once I have enough shots to ensure the scope is sighted in, clean said barrel with Wipe Out foaming bore cleaner. Dry patch as per the instructions on the Wipe Out can and then commence load development. This consists of 3 or 4 fouling shots and a couple of 5 shot strings fired for group size.
Re-clean bore and repeat until happy with the group the load produces.
Once load is determined shoot rifle until group size opens up, then clean.
ATRS does NOT recommend the use of Bore Snakes or non coated rods having seen far too much damage resulting from improper use.
I do not think there is any proven and definitive manner that proves barrel break in is anything but a bunch of opinions.
The opinion expressed is simply my own and reflects what has always worked for me.
YMMV
And she's locked.