breaking in a barrel

[dxt20]

what is the easiest way to break in a new barrel?

[ozark]

I am hoping to learn something from this thread. I have never thought a new barrel needed any breaking in. I have always just started using them and have never noticed that they became more accurate or less accurate after being fired a few or many rounds. Maybe someone will educate us bothe dx120.

[Richard]

This can vary according to the barrel. In my opinion, custom benchrest quality barrels need very little breaking in. They are, for the most part, machined to be smooth from the start. On the other hand, factory barrels are notoriously rough. That is, there are lots of groves, both length wise and cross wise, that can trap copper.......hence copper fouling! Some factory barrels are made to better standards than others. One area common to both is the throat. From the barrel turning around the reamer (in the lathe) where the leade angle is being cut into the rifling, it can leave some metal hanging off the lands and into the groves. Here again, some of this is relative to the sharpness on the reamer. Picture a knife which is dull, cutting a piece of paper or any type of material..........Then picture that same material being cut by a new razor blade? One a clean cut.....one a jagged cut. Now think about those lands where the throat is being cut by the sharp/dull reamer?
If the leade angle is cut by a sharp reamer (custom gunsmiths then to use a sharp reamer), there will be little or no jagged edges. On the other hand, the factory will get many chamberings on a reamer before it is sharpened. Obviously, the one cut with the sharpened reamer will be cleaner than later cuttings. So, it depends on where in the reamers cycle, your rifle's chamber was cut? What the break in does, is to help clean up this roughness in the leade. Also, it will help to sort of "iron out" some of the imperfections within the bores lands and groves.
The general procedure is fire a shot and then clean. That shot, going past the rough leade and bore tends to drag and deposit copper throughout the bore. This should be removed prior to the next shot. So shoot and clean for at least the first five to ten shots. Then go to three shot strings of shooting and cleaning for about five cycles and then to five shot groups with cleaning between groups for another few. As the leade and bore smooth out, copper fouling should decrease. If it does not go away, bore lapping might need to follow. Because the custom lapped BR barrels are smooth to start with and chambers are cut with sharp reamers, not as much break in is required.
Fire lapping a rough bore can greatly decrease bore copper fouling.
What I do after cutting a chamber is this: I take a cleaning rod with a patch and some lapping compound and run it in to the leade and then short stroke it maybe twenty times. This will cut the sharpness from the sides of the lands and make break in not necessary.
Richard

[ozark]

Good description Richard, Thank you. Now, a question: Have you noticed damage done if a barrel isn't properly broke in or better accuaracy afterwards? I have noticed that after having a rifle apart it sometimes takes a few shots to settle the action back into the stock. dxt20 I don't mean to hijack your thread. Sorry

[dxt20]

I'm not worried about it. i would like to hear what other people have to say about it

[ricksalisbury01]

Here is how I do it: www.gaprecision.net/ga-precision-download.html This is fro GA Precision and I like the process.

[rossman40]

I have to agree with Richard, the difference between a high end cut rifled and well lapped barrel compared to some button rifled barrels is night and day. The quality aftermarket button rifled barrels are far better then the OEM because time is taken and attention to the tooling is far greater. A well broke-in barrel will not foul as fast and what gets you is fouling, as fouling builds up chamber pressure curves get ragged and then your MV/SDs become inconsistent. For the guy shooting 100-200yds no big woop, but for the guy shooting longrange and trying to get every .1 (maybe even .01) MOA of accuracy it counts.

A cut rifled barrel is just about ready to go out of the box but there are the finer points such as chambering and crowning burrs that may have to be addressed as Richard mentioned.

With the button rifled barrels what happens is there are almost microscopic shards mainly on the lands (some of these shards may not even appear to the barrel is shot). A good lead lapping will take care of most of these but what happens is during firing the copper goes underneath the shard and lifts it up so it can catch more copper the next shot and be lifted more. Eventually what will happen the shard gets ripped out possibly leaving a sharp edged chunk out of the edge. During the break-in what you are doing is after one shot you de-copper and hit it with a brush to try to knock off the shards before they get bigger and are ripped out by the bullet.

Now you will get some shards even in a cut rifled barrel. A quality button rifled barrel more. A OEM barrel that is done in less then 45 seconds with dull tooling your going to get a lot more. Supposedly Remington a few years back cut the times on the drilling, reaming and button rifling their barrels by 1/3 in the name of productivity. Their button rifled barrels have been POSs since (one smith told me Savage barrels look good compared to some of the Remington barrels he has seen).

Supposedly SS will have more shards then chrome moly and a good barrel maker will pay attention to which direction the barrel was cut or pulled to help reduce the factor.

[whelenman]

I've always fired one shot and cleaned up to shot number five and then every five shots until I've gotten up to 30 to 50 rounds. I use a brass brush saturated with Butches Bore Shine for about 10 laps followed by a clean patch...then Butches Bore Shine on a wet patch followed by a couple of dry patches. Then swab the chamber with a clean cloth. The brush helps to break the edges and polish the sharpness of the edge. Don't even think of cleaning a good barrel unless it's from the breech and with a bore guide. The number of strokes is according to the barrel.....some less......some more. Like Rossman40 said good barrels require very little......bad barrels more. Nowadays I shoot mostly hand lapped Shilens and Kriegers which are all lapped. Very little is required. I spend more time removing carbon deposits than copper fouling.

[Tarheel]

Just shooting a rifle will lap the barrel, eventually. IMO lapping is far less a accuracy factor than barrel concentricity and straightness. Of course a premium barrel will have closer tolerences than a mass produced factory barrel, hence the price. I believe barrel harmonics are the single biggest accuracy factor. IMO

[Richard]

Ozark.......I don't think you will actually damage the barrel, it will just accumulate copper faster? I think all factory barrels would probably like a light "fire-lapping" to break them in. Get yourself a small can of 500 grit Clover lapping compound, two flat pieces of steel plate, put some Clover on it and roll your jacked bullet in between the plates. You will impregnate the grit into the copper jacket. Use a mild load and fire; then clean and repeat maybe five times. Those five shots will do more to improve your bore than probably a couple of hundred rounds.
Richard

[dxt20]

what i did is what varmint AL does... i shot the rifle 5 times. then i cleaned it very good with sweets 7.62. then i took jb bore brite and ran about 60 patches threw it with a 7mm brush with the patch on the outside (the gun is a 308 and a 7mm is just a little bit littler bullet diameter) it gives a good tight fit but not to tight... then i cleaned the barrel out with shooters choice and hoppes # 9. in order to get all the jb bore brite out. now i just shoot it. thats all there is... no cleaning every 3 or 5 shots. just clean it when the copper builds up. easy as that