I wish I'd been that lucky. I generally consider 1 1/2" acceptable with the more affordable factory sporter weight rifles, i.e. Ruger, Winchester, Remington, etc., and I've had a number of factory rifles that wouldn't do that well. Although in all fairness I've had some that were tack drivers.

But back to his break-in question. I've tried various methods though the years, but I gave up on them. I never saw any real improvement.