I don't do it. Certain premium barrel makers demand it, other premium barrel makers call it hooey.
A couple of years ago I'd found an article online by a benchrest shooter, who set out to demonstrate what happens when you don't break in a barrel properly...just to shut-up all the naysayers.
He ended up converting himself to the "no break-in required" camp.
If you choose to purchase a rifle or a barrel with a warranty conditional upon proper break-in, then do it.
For the experience, you should try hand lapping once also.
And for what it's worth, if you've fired five whole rounds at this point without following the procedure of a break-in, you've already voided someone's warranty.
Shoot it.
Jon