"Break In' procedures are touted as the method of removing the tooling / machining high points off the lands of the gun's barrel.
If your firearm is CHF (Cold Hammer Forged) then stop reading right here - there are no tooling / machine remnants to polish off. (SIG pistols, Swiss Arms, Danial Defense, etc.)
Otherwise - one camp of shooters are gonna tell you to take a certain amount of shots, then clean the barrel.
Then there is the other camp that will tell you to shoot a bunch of rnds through the barrel without cleaning it, as the residue left behind creates a 'lapping compound' of sorts to aid in the removal of said machining marks.
And finally there is the group that just says shoot the weapon, and clean it when it becomes fouled.
Your choice my young friend - this debate will go as long as the DI vs. Piston debate.
Abby