An article I posted in February...
From Reloadersnest.com
Larry,
A break-in procedure in any of the accepted forms won't hurt your rifle. So if you choose to do one, it will also fit into your required fireforming anyway. The fireforming will just take a little longer. Many folks use a break-in so that they don't have to regret not doing it later in case a barrel doesn't perform up to their expectations. Superstitious. Please bear in mind that this is a "well-documented procedure" (and argument), but it does not necessarily provide "ultra accuracy results" by any means. There are always going to be mediocre barrels and poor barrels and sometimes we get one of those and there isn't anything that you can do about it except to send it back to the maker and see if they will exchange it. But for the most part, we are truly blessed with a large majority of top flight barrels and barrel makers.
I've seen those 1 hole targets from the factory and on 4 ocassions, we couldn't get those rifles to shoot like their targets. We called the factory and discussed the problem and they gave us their loads. Still not up to the targets shipped with the rifles. We shipped the rifles back and the barrels were switched. Good customer service! I wouldn't worry.
Plasma from the burning powder will melt the very tiny burrs that are present in some barrels. However, and you can take this to the bank, there is no copper clad bullet or plasma that will remove machine marks. Machine marks have to be lapped out. Barrel steel runs between 22 and 28 Rockwell and copper just isn't going to do any smoothing without having something abrasive on the surface of the bullet. The plasma turns the surface of the steel into what is referred to as alligatoring because it resembles the texture of alligator skin but this is after many hundreds of shots and extreme heat.
I will say this once more, the very best barrels are lapped by the maker at least once if not twice with a lead lap and some form of fine lapping compounds. These barrels usually don't need any more than a few shots to get the barrel to stop coppering.
Gale McMillan, one of the Deans of Barrel Makers and record holder wrote a series of responses to a group of folks concerned about barrel break-in. He categorically denied that it did anything to enhance the accuracy of a well made barrel.
"Hint: overheating is not the critical factor."
And just to finish up this discussion, here is a statement by Ernie Stallman, another one of the Deans of Barrel Makers and a noted competition shooter.
BREAK-IN PROCEDURE FOR BARRELS by Ernie Stallman/Badger Barrels
Jacketed bullets
For the first ten shots we recommend, if possible, using jacketed bullets with a nitro powder load. Clean the oil out of the barrel before each shot using something as simple as Windex which will soak the oil out of the pores. After firing each bullet use a good copper cleaner (one with ammonia) to remove the copper fouling from the barrel. We do not recommend anything with an abrasive in it since you are trying to seal the barrel, not keep it agitated.
After cleaning with bore cleaner, clean with Windex after each shot. Use Windex because many bore cleaner use a petroleum base which you want to remove before firing the next shot. This will keep the carbon from building up in the barrel (oil left in the pores, when burned, turns to carbon).
To keep the temperature cool in the barrel, wait at least 5 minutes between break-in shots. The barrel must remain cool during the break-in procedure. If the barrel is allowed to heat up during the break-in, it will destroy the steel's ability to develop a home registration point, or memory. It will have a tendency to make the barrel "walk" when it heats up in the future. I am sure we all have seen barrels that, as they heat up, start to shoot high and then "walk" to the right. This was caused by improperly breaking in the barrel (generally by sitting at a bench rest and shooting 20 rounds in 5 minutes or so). Then, for the rest of the guns life the man complains that barrel is no good. If you take a little time in the beginning and do it right, you will be much more pleased with the barrel in the future.
If you look into the end of the barrel after firing a shot, you will see a light copper-colored wash in the barrel. Remove this before firing the next shot. Somewhere in the procedure, around shot 6 or 7, it will be obvious that the copper color is no longer appearing in the barrel. Continue applications through shot 10.
If you have any ammunitions left, you then may shoot 2 rounds and clean it for the next 10 shots. this is simply insuring that the burnishing process has been completed.
IN theory you are closing the pores of the barrel metal which have been opened and exposed through the cutting and hand lapping procedures.
FWIW...
