This version, from Krieger's website, is the one I choose to believe.
BREAK-IN & CLEANING:
With any premium barrel that has been finish lapped -- such as your Krieger Barrel --, the lay or direction of the finish is in the direction of the bullet travel, so fouling is minimal compared to a barrel with internal tooling marks. This is true of any properly finish-lapped barrel regardless of how it is rifled. If it is not finish-lapped, there will be reamer marks left in the bore that are directly across the direction of the bullet travel. This occurs even in a button-rifled barrel as the button cannot completely iron out these reamer marks.
Because the lay of the finish is in the direction of the bullet travel, very little is done to the bore during break-in, but the throat is another story. When your barrel is chambered, by necessity there are reamer marks left in the throat that are across the lands, i.e. across the direction of the bullet travel. In a new barrel they are very distinct; much like the teeth on a very fine file.
When the bullet is forced into the throat, copper dust is removed from the jacket material and released into the gas which at this temperature and pressure is actually a plasma. The copper dust is vaporized in this plasma and is carried down the barrel. As the gas expands and cools, the copper comes out of suspension and is deposited in the bore. This makes it appear as if the source of the fouling is the bore when it is actually for the most part the new throat.
If this copper is allowed to stay in the bore, and subsequent bullets and deposits are fired over it, copper which adheres well to itself, will build up quickly and may be difficult to remove later. So when we break in a barrel, our goal is to get the throat "polished without allowing copper to build up in the bore. This is the reasoning for the fire-one-shot-and-clean procedure.
Every barrel will vary slightly in how many rounds they take to break in For example a chrome moly barrel may take longer to break in than stainless steel because it is more abrasion resistant even though it is a similar hardness. Also chrome moly has a little more of an affinity for copper than stainless steel so it will usually show a little more color if you are using a chemical cleaner. Rim Fire barrels can take an extremely long time to break in, sometimes requiring several hundred rounds or more. But cleaning can be lengthened to every 25-50 rounds. The break-in procedure and the cleaning procedure are really the same except for the frequency. Remember the goal is to get or keep the barrel clean while breaking in the throat with bullets being fired over it.
Finally, the best way to tell if the barrel is broken in is to observe the patches; i.e. when the fouling is reduced. This is better than some set number of cycles of shoot and clean as many owners report practically no fouling after the first few shots, and more break-in would be pointless. Conversely, if more is required, a set number would not address that either. Besides, cleaning is not a completely benign procedure so it should be done carefully and no more than necessary.
+1
well said
Before I totally believed in brake-in I tried a test on a new rifle. I shot 50 rounds through a 416
Remington without cleaning.(It was the only new rifle I had at the time)
Using the same ammo and shooting 5 shot groups on separate targets, I monitored each group
to see if there was any improvement/change.
The best group was the first one. after the second group it settled into a very consistent 1'' group for all the others. I was ok with that because of the service that the 400 grain bullets would be used for.
After getting home I started the cleaning process (Something I had learned well while shooting NRA matches. I first looked through the bore and saw lots of copper fouling (Not to surprising) and started the cleaning process.
After 1 hour of cleaning I began to wonder about the wisdom of shooting this much without cleaning
and if a brake-in would have helped. 3 hours later and hundreds of patches it finally came clean.
So I vowed never to shoot this rifle that much with out some cleaning. (also to take better care of my shoulder) I also thought that this rifle might be the exception as far as fouling and just be worst than others.
This is when I got the idea to do a brake in on it because the fouling had prevented brake -in by covering the bore with a lot of copper not allowing the bullet to condition the bore.
The next session at the range was very informative. The set up and ammo was the same and the rifle was clean just like when I started the first time.
The first 5 shots with cleaning were slightly better than the first 5 from before I also noticed that cleaning was effortless 2 or 3 patches and the bore was clean. (Of course I realized it should be better because I had only shot 1 round round through it without cleaning)
The thing I noticed most about the break -in process was the feel of the patches in the bore. They got easer and easer to push through the bore the more shooting and cleaning I did.
The second 5 shot group (10 rounds through the bore) the groups got even better than the first and much better than the 50 shot groups that I had shot before. I though to my self, Maybe I am just having a better day But decided to proceed as long as I saw improvement.
The 3rd group was even better (15 rounds through the bore) and while cleaning the barrel I noticed
the bore felt greasy(very smooth). By now I was getting tired of getting the crap kicked out of me but wanted to continue, so I decided to fire a 5 shot string without cleaning (20 rounds down the bore) The rifle shot very well just under 1/2" (the best it had ever shot) so I gave it up and went home.
Deciding to clean when I got home, after only 2 swabbing's with solvent and 3 patches it was clean.
This was a factory barrel and sometimes they will take more shoot and clean shots to reach that point where they clean up easy. The custom hand lapped barrels take far less to get to that point
(7 to 10 shoot and cleans)
Others have different experiences and beliefs but I am convinced that brake-in improves cleaning and extends barrel life.
End of story
J E CUSTOM
