Yes, absolutely break the barrel in properly.

My gawd people you make it sound like slave labor.

Clean thoroughly before your range session.
After every 3 shot group clean again.

If you're shooting properly you will be allowing your rifle to cool before the next group anyway. What are you going to do while you wait for it to cool? Run a few patches of bore solvent through it. patch dry. Run some copper removal (sweet 7.62 is the best). Patch dry. run patch with light oil through. After that 10 minutes of slave labor. You will still need to let the bore cool for another 10 most likely.

If you take the time to follow these steps, you will end up with a rifle that is easy to clean. You won't get a more accurate rifle, but you will end up with one that doesn't foul as badly.

Most of the folks that mock the break in process cant see the forest for the trees. They don't want to go to the trouble so they say its rediculous. I build semi custom rifles for myself and friends. Altogether we probably built 15 rifles last year. All with custom barrels and all where broken in. Its not difficult, you just do it during the sighting in and load development.