From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: "Hardness" of Barrel steel & cleaning rods?
Organization: Hewlett-Packard Fort Collins Site

K. Karcich (kkrh@troi.cc.rochester.edu) wrote:

: I choose not to use coated rods,jointed rods or non-ferrus rods. For my 22-250
: I made up a little steel bore guide that slips into the bolt raceway to guide
: the rod. It would be quite simple to make up a muzzle cap for those barrels
: that had to be cleaned from the muzzle. Since with this setup, *my* rod does
: not actually touch the edge of the bore, one could in theory use any kind of
: rod.

This is what smallbore shooters did over 50 years ago.  But they found out
the bare steel rods were ruining the throat as they scraped over it.  Even
with proper cleaning rod guides, the rods still bent enough in the bore to
damage the rifling.  Parker-Hale (another great product from England) rods
are coated with a nylon-like substance and soon became the rage of these
mousegunners.  No more ruined barrels.  Accurate life was about tripled in
some situations.

Benchresters found this out too; they also use coated rods.

I suppose that if the rod guide's hole was cleaning rod diameter plus
a couple of thousandths of an inch, the rod may not rub on the origin
of the rifling.  But I'm not aware of any commercial rod guides with
that small of clearance to the cleaning rod.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: Frequency of cleaning
Organization: Hewlett-Packard Fort Collins Site

Gary Coffman (gary@ke4zv.atl.ga.us) wrote:

: It's not the brass brush, it's the gritty steel rod that's pushing
: it. A bullet goes down the barrel *concentric* to the bore (at least
: we *hope* it does), but that dirty rod is going to scrape the bore
: *eccentrically* unless we are very careful. In a barrel that we paid
: good money to have made with a tolerance of 0.0001 bore uniformity,
: that eccentric wear is a very bad thing, especially at the muzzle
: crown.

I'm not convinced that it's all that important to be `very careful'
during bore cleaning with an uncoated steel rod.  Especially with bores
of 27 caliber or greater.  As long as a rod guide is used in the
receiver's boltway and it's a decent one, the rod won't get far enough
off center to damage the throat.  And it won't damage the bore surfaces
between the throat and muzzle.

The important thing seems to be to keep the rod from bending.  Which
means that for bores larger than 27 caliber, a solid steel rod will be
stiffer than a coated one; it'll bend less when the brush/patch is
pushed down the bore.  Smaller caliber bores just about always need a
coated rod because they'll bend more and their coated sides do bear on
the bore.  Hundreds, if not thousands, of top shooters agressively
clean their target barrels with both brush and patches, but they use a
rod guide.  If there was any measurable degradation in accuracy from
agressive cleaning, these folks would notice it and would quickly go to
a gentler, kinder cleaning process to preserve the gilt-edge accuracy
the barrel maker lapped into the bore.

Nor am I convinced that eccentric wear at the crown, nor even back into
the bore, will reduce accuracy.  Back when the M1 was `the' service rifle
for competition, it had to be cleaned from the muzzle.  Solid steel rods
were used.  Many of these rifle's barrels had been cleaned enough that
the copper wash stopped 1/4 to 1/2 inch back from the crown; when new,
the wash went all the way to the muzzle.  The worn area without copper
wash was typically longer at one point than the others due to the way
angle the rod was to the bore axis during cleaning.  Accuracy did not
degrade as the wear increased over the life of the barrel.  Remember
that the bore/muzzle condition did remain the same for each shot of a
string.  There may have been a very slight shift in zero, but not enough
for the top shooters to have concerns about it.  All four of the M1
barrels I wore out exhibited this condition.

BB

From: bartb@hpfcbart.fc.hp.com (Bart Bobbit)
Subject: Re: barrel wear
Organization: Hewlett-Packard Fort Collins Site

Bullets actually cause virtually no wear at all in barrels, given the
same material used in the barrel for either jacketed or lead bullets.
99.99% of barrel wear is caused by the burning powder's high temperatures.
Jacketed bullets typically are used with powders that produce higher
pressures, hence higher temperatures.  That's often confused with the
bullets causing wear.

If a barrel is on the soft side, such as those used many years ago for
lead bullets, then it will wear out faster.  The hot, high-pressure gases
will erode it faster than if a harder barrel steel was used.

Improper use of a cleaning rod will probably cause more barrel wear than
lead bullets.  And the cleaning rod's material can also be a basis for
increased barrel wear.  Aluminum and brass cleaning rods readily hold
abrasive material and rub that stuff back and forth against the bore,
causing more removal of barrel metal than the bullet does.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Subject: Re: [RIFLE] best way to clean 10/22?
Organization: Hewlett-Packard Fort Collins Site

You could use a coated steel rod inserted into the muzzle.  I doubt if
that will cause any damage to the crown at all.  This would be a lot
easier than disassembling the rifle to clean it from the breech anyway.

I'm convinced that cleaning rifles from the muzzle end is not nearly
as detrimental to accuracy as most folks think.  My reasoning is based
on wearing out three 7.62mm NATO barrels in M1 rifles.  When new, each
of those barrels shot sub-MOA 20-shot groups at 600 yards.  About 5000
rounds or more was fired through each barrel before replacing it.  I
used a GI solid steel cleaning rod without any muzzle protector at all.
Cleaning was done about every 30 to 40 shots.  After about 1000 rounds
in each barrel, I noticed that the copper wash ended about 1/16th of
an inch back from the crown.  With a new barrel, that wash went all the
way to the crown.  After each successive 1000 rounds or so, the copper
wash was further back another 1/16th inch or so.  At about 5000 rounds,
the wash ended near 3/8ths inch back; clear evidence the cleaning rod
was wearing away barrel metal and making the bore/groove diameters
larger where the rod rubbed against the bore.

But most interesting was accuracy levels remained constant for each
barrel through their 5000+ round life.  One of these barrels was air
gaged. 'Twas found to be a few thousandths of an inch larger in diameter
at this wear point.  Which explains why the bullet's jacket didn't get
rubbed off at this place.  There may have been some gas escaping around
the bullet before it cleared the muzzle.  Each barrel had quite uniform
wear around the circumference of the bore.  I must have run the cleaning
rod in and out at all angles enough to cause uniform wear all the way
around.  In checking out other M1 barrels, one had the wear point only
at the bottom of the bore; copper wash went all the way to the crown in
the top half, but not at the bottom half.  This implies that rifle's
owner had the cleaning rod rubbing against the bore's bottom half.  But
this rifle also shot sub-MOA groups at 600 yards with 1/4th inch of no
copper wash at the bottom part of the bore.

The fact is that all of these barrels with varying degrees of wear at
the muzzle from cleaning rods shot very accurate.

BB

From: bartb@hpfcla.fc.hp.com (Bart Bobbitt)
Newsgroups: rec.guns
Subject: Re: "Hardness" of Barrel steel & cleaning rods?
Date: 18 Feb 1994 10:37:39 -0500

Cleaning .22 caliber bores should only be done with a coated rod.  Those
made by Parker-Hale and Dewey are excellent.  Their steel core does bend
somewhat and it's the coating on the outside that prevents the steel
from scraping the bore.

Any bare metal cleaning rod used in .22 and .24 caliber bores will 
eventually reduce its accuracy.  Whether one notices this in their
shooting is another issue.  But it does happen.  Brass and aluminum
rods are the worst culprit; they carry embedded abrasives back and forth
in the bore further lapping away the top of the lands.  Stainless steel
rods don't let abrasives embed in them, but they do bend and that makes
'em rub against the bore hard enough to cause damage.

Stainless steel rods are tougher than chrome moly barrel metal but about
equal to stainless steel barrels.  Chrome moly steel cleaning rods may
or may not be harder, softer, more or less tougher than the barrel metal.
Only comparison of the specific barrel/rod metallurgy and tempering will
tell; something few folks can measure or determine.

Jointed rods of any type are best used in ones garden to let tomatoes
entwine their branches on.  When used in bores, the micro-step at each
joint acts much like the business end of a cold chisel when it goes into
the muzzle crown or chamber leade.  I prefer not to put an extra micro-
rifling groove, or more, in my barrels with such rods.  

Bores larger than .270 can be safely cleaned with uncoated, solid, one-
piece stainless steel cleaning rods.  Their cross sectional area is more
than twice that of a coated rod for .22 caliber bores; about 4 times as
stiff.  They don't bend enough to damage the tops of the lands.

A cleaning rod guide, either muzzle or breech type, is essential if one
wants to preserve their barrel's accuracy as long as possible.  These
things keep the rod entering the bore much straighter than us mortals do
by look, touch and guess.  Doing this keeps the front and back parts of
the rifling from being lapped away maintaining whatever accuracy level
the barrel has.  Again, we get to choose what we do to preserve our
favorite barrel's accuracy.

BB

From: bartbob@aol.com (Bartbob)
Newsgroups: rec.guns
Subject: Re: Are aluminum cleaning rods really that bad?  Was Re: Gun Cleaning
Date: 23 Jan 1997 21:45:29 -0500

Regarding these words:

" ......it is easy to ding the muzzle with the edge of the rod on guns
like the M1 that get cleaned from the front. The tinniest dent here is a
giant speed bump to the
bullet."

I've wondered about this for years.  In all four 7.62mm NATO M1 barrels I
wore out, each one exhibited the same wear at the muzzle from the solid
steel cleaning rod I used.  After about 4000 rounds had gone through each
barrel and the barrel being cleaned after each 50 to 80 shots, there was
enough metal on both bore and groove surfaces that no copper flash was
present.  The micro-thin copper plating from bullets wasn't on the metal
for about 3/8ths of an inch down the muzzle.  When new, the barrels showed
this plating (or fouling) extended all the way to the crown.  I believe
this is caused by the barrel being worn away from cleaning rod movement
enough to open the diameters enough so the bullet no longer touches the
bore at the muzzle.

Yet accuracy was still excellent.  Accuracy cradle tests resulted in
300-yard 20-shot test groups to be about 2.5 inches with the barrels at
about 4000 rounds and no bullet jacket material on the last 3/8ths of an
inch of bore.   When new, the barrels shot about the same group size;
close enough to be statistically the same.

Perhaps because the wear was probably uniform all the way around, accuracy
wasn't decreased by cleaning rod wear.  But for whatever reason things
were like they were for the lives of 4 barrels, this amount of cleaning
rod muzzle wear didn't appear to be detrimental to accuracy.