A few months ago, I received this note from reader Jon Morigi in Farmington, PA:
“What do you suggest is the proper break-in procedure for a new rifle? I have read several procedures over the years and don’t know which is correct. Is there a different break-in for blued versus stainless?”
Here’s the short answer: If you clean your barrel every 10 shots or so for the first 50 rounds, you can rest easy at night and, no, there’s no need to differentiate between stainless and blued barrels.
Here’s the longer version: There’s little agreement on how to break in a barrel, and that right there should be a clue that this isn’t a rigid science. (One well-known barrel maker told me the only reason he ships barrels with instructions for this, which he made up arbitrarily, was to stop the calls from customers bugging him for the information before he had a break-in process.)
In practical terms, breaking in is done to smooth out any rough spots in the barrel by depositing some copper fouling along its length. But without knowing the condition or quality of the rifling of your barrel before you start, you can’t tell how much breaking in you should do–or if the barrel will benefit from the process at all. The best course of action is to clean your barrel periodically in the beginning and see if it settles in and delivers better accuracy.