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BARREL BREAK-IN PROCESS
By Wayne McLerran
Posted: 5/31/15

When breaking in a barrel the goal is to burnish (smooth out), down to the
microscopic level if possible, any chamber reamer marks in the throat or rough
edges in the lands and grooves from the broach cutting process.  A smoother throat
and bore is less likely to lead.  But barrel break-in is somewhat of a controversial
subject.  Most if not all rifle and barrel manufacturers publically recommend it but
some manufacturers will privately admit it may not be necessary, especially for
barrels with lapped (polished) bores.  I’ve discussed the subject with several barrel
producers and distinctly remember one such discussion a few years ago with the
owner of a high-end cut-rifled barrel manufacturer.  Since the bores were lapped
after the riflings were cut he was not convinced breaking-in his barrels was
necessary.  But rather than spend time discussing and debating the subject at length
with numerous customers, it was more expedient to “side step” the issue and post a
procedure on their website since most of his customers were convinced that a
break-in process was necessary.

While buying and selling scores of Browning and Winchester BPCR, many
customers requested recommendations on a barrel break-in process.  Since the
rifles feature Badger cut-rifled barrels, my standard response was to refer them to
Badger’s website for their step-by-step instructions.  Since Badger Barrels is no
longer in business their procedure is listed below.  I’ve also included a much
simpler approach developed by Lee Shaver that I will be using from now on.

By the way, breaking in a barrel does not just apply to a new rifle.  A used rifle
can also benefit from the process, especially if the bore was never properly cleaned
between shooting sessions and was fouled from the beginning with copper and/or
lead and carbon residue.  With a used rifle it’s very important to ensure the bore is
absolutely clean prior to starting the break-in process or it will be a waste of time.  
Here’s where Lee Shaver’s break-in technique “shines”.  It not only saves a lot of
time and effort, but very effectively removes all fouling during the simple and short
break-in procedure.

Badger Barrel’s Break-In Procedure

Break In with Jacketed Bullets:
For the first ten shots we recommend, if possible, using jacketed bullets with a
nitro (smokeless) 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 cleaners 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" when it heats up.  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 gun's life the man
complains that the 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 cleaning between each shot with Windex
and an ammonia-based cleaner through shot 10.

If you have any ammunition 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 culling and hand lapping procedures.

Break In with Lead Bullets:
The same shooting/cleaning break-in process may be used when firing lead bullets
and black powder with the following exception: shoot 2 bullets, than clean and
repeat the process after the barrel has cooled.  Naturally, you must use a cleaner
appropriate for removing lead and black powder fouling.  You can also use harder
lead bullets if available to accelerate the break in.  This will accomplish the same
as the jacketed bullets but it will take 80 to 100 rounds to break in the barrel with
lead bullets.  That is why we recommend using jacketed bullets when possible.

After this procedure, your barrel’s interior surface will be sealed and should shoot
cleaner and develop less fouling for the rest of its shooting life.

Lee Shaver’s Break-in Procedure

Having used the jacketed bullet/clean-between-shot process in the past and
specifically Badger’s procedure when breaking-in one of my Browning BPCRs, I
was not looking forward to repeating the very lengthy process with my other
Browning’s.  Fortunately Lee Shaver came to the rescue with his much simpler and
less time consuming process.  With permission from Lee I’ve included the details
of his procedure.  It’s from a larger article Lee published in the May 2013 edition
of The Single Shot Exchange Magazine.

Excerpt from “Breaking In a Barrel” by Lee Shaver:
Several years ago, I developed a process for breaking-in barrels for lead bullet use
that eliminated the afternoon of shooting and cleaning with jacketed bullet.  It
began because I would occasionally have to get bad leading out of a barrel for a
customer, and when you charge what a gunsmith must charge to stay in business
you don’t want to spend an afternoon scrubbing the lead out of a customer’s gun.  
And I’m sure the customer would rather not pay for said services.

What I learned was that when scrubbing lead out of a barrel, I could run a tight oily
patch through a few times and then take the patch off the jag.  I would then unroll a
little 0000 steel wool and cut a piece the size of the patch.  Place that over the
patch and then run it all through together.  (The proper fit is when you have to
bump the rod a few times with the palm of your hand to get it started in the bore.)  
When you shove that steel wool over a patch through the bore of a badly leaded
barrel, it may sound like paper tearing as the lead is ripped out of the barrel in a
pass or two.  I can clean the lead out of the worst barrel in about ten or fifteen
minutes that way, and an average leaded barrel will be clean in a few strokes.

After using this technique for a while, I began to notice that the rifles that I was de-
leading that way seemed to lead less afterwards, which got me to thinking.  We use
fine steel wool on the outside of old guns all the time to do some cleaning or spot
rust removal, and it does not damage the surface of the steel.  It just scrubs it.  
Which lead me to consider the fact that we are trying to break in a barrel by
smoothing the surface without cutting, and it seems to me that process would go
much quicker if we used something on the inside of the bore that was closer to the
hardness of the barrel instead of lead or copper.  So I started trying the steel wool
and oiled patch technique on new barrels before shooting them.  I use it about as
tight as I can get in the bore and wear out a steel wool pad or two in about 15
minutes, then I go and shoot the rifle.

How well does it work you might ask?  On a few occasions, I have built a new rifle
and taken it to a match without ever having fired the rifle.  All have performed
flawlessly in their first match and several times I won the match or set a record
with them.  On one occasion, I set a new 300 yard range record with the first 13
shots out of a barrel.  This method has become a service we offer to our customers
here in the shop and I have shared the technique many times with others.

So the next time you get ready to shoot that new rifle, just remember it is important
to break in a barrel properly, but if the operation you are doing to the barrel cuts –
it is not breaking it in.  It may be making the barrel smoother, but to break the
barrel in you need to polish the bore by burnishing not cutting either by shooting it
or scrubbing it.
Lee Shaver


Wishing you great shooting,
Wayne