1903A3 Barrel Change

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A strong work bench .
A padded vise.
Barrel vise.
Breaker bar and applicable socket.
Action wrench and a cheater bar.
Headspace reamer/bushing and extension rod. Pull through
usage described in this presentation.
GO and NO-GO 30.06 headspace gages.
Small toothbrush sized stainless or bronze brush.
Kroil or other good penetrating oil.
Cutting oil.
A good solvent..
Anti-seize.
A white paint pen.
Aluminum can, something to cut it with and tape.
Rags and pans to catch the mess you’ll make.
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Put the barreled
receiver in a
padded vise, barrel
up a day or so
before you begin.
Apply Kroil to the
shoulder area
several times a day
to aid in barrel
removal.
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Lay out the tools
you will need for
the project.
Provide yourself
with plenty of
light.
USE A GOOD SOLVENT TO REMOVE
ALL OIL AND GREASE FROM THE
BARREL AND RECEIVER WHERE THE
BARREL VISE AND ACTION WRENCH
WILL BE INSTALLED.
ALL OIL NEEDS TO BE REMOVED TO
PREVENT SLIPPING
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Depending on your
action wrench find the
best angle to clamp the
BR in the vise to give
you maximum pulling
leverage.
Mine was upside down
at a slightly clockwise
angle.
Clamp the barrel very
tightly in the vise very
close to the receiver on
the un-tapered part of
the barrel.
CUT A STRIP FROM AN ALUMINUM
CAN TO PLACE BETWEEN THE
RECEIVER AND THE ACTION
WRENCH TO PREVENT MARRING THE
RECEIVER FINISH.
WRAP THE ALUMINUM AROUND THE
RECEIVER AS FAR FORWARD AS
POSSIBLE AND TAPE IT IN PLACE.
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Clamp your action
wrench on the
receiver, over the
protective strip as
far forward as
possible toward
the barrel.
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You may need a cheater
for your action wrench.
When you are ready,
brace yourself well and
pull hard on the wrench
to break the receiver free
from the barrel. This
may not be easy…this
one wasn’t but I didn’t
need the cheater.
If the barrel slips tighten
it more or add rosin to
prevent slippage.
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The receiver has
broken free from
the barrel.
REMOVE THE ACTION
WRENCH FROM THE
LOOSENED RECEIVER.
TURNING COUNTER
CLOCKWISE UNSCREW THE
RECEIVER FROM THE BARREL.
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Loosen the vise
and remove the old
barrel from the
vise.
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I use a small
stainless brush to
clean the threads
but any small
toothbrush sized
steel or bronze
brush will work.
Clean the threads
thoroughly.
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Buff the threads on
the new barrel well
to smooth out any
rough finish.
Carefully brush the
shoulder of the
barrel.
I USED A WHITE PAINT PEN AROUND
THE WITNESS MARK, LET IT DRY AND
LIGHTLY WIPE WITH ACETONE. IT
LEAVES A VISIBLE WHITE LINE
THAT’S EASY TO SEE.
DO THE SAME WITH THE RECEIVER
WITNESS MARK.
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Clamp very tightly
using a breaker bar
leaving the witness
line barely visible.
Be sure the witness
line will be visible
when indexing or
visible to a helper
while you tighten
the receiver.
VERY LIGHTLY LUBRICATE THE
BARREL THREADS WITH ANTISEIZE AND WIPE OFF THE EXCESS.
DON’T OVERDO IT, JUST A LIGHT
COATING. WIPE OFF THE EXCESS.
VERY LIGHTLY LUBRICATE THE
RECEIVER FACE TO AID IN
DRAWING UP THE RECEIVER.
WIPE OFF THE EXCESS.
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Turning clockwise screw
the receiver on as far as
it will go by hand.
Note the position of the
witness lines. Too far
apart may require
machining back the
shoulder of the barrel.
I have drawn up as
much as ½” (this one
was ½”).
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Tape the aluminum
strip back on the
receiver and attach
the action wrench.
You are probably
going to need a
cheater during this
operation to line up
the witness lines.
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Line up the two witness
lines to achieve proper
index.
It may require
tightening and
loosening several times
to enable you to draw
up the receiver to line
up the lines.
This one took four
operations but they
eventually lined up.
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If you installed a new, short chambered barrel
it will require headspace reaming.
This can be done with a finish reamer from the
chamber end or a pull through reamer from the
muzzle end.
This presentation will show the use of the more
versatile pull through reamer only (it’s all I
have).
A pull through reamer can be used for both
bolt guns and M1 Garands.
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Lay out the tools
and materials you
will need for the
reaming operation.
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Clamp it by the
barrel well in front
of the receiver to
allow room to
work.
This operation will
be messy if done
right so lay out
rags, etc. under the
work area.
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Pour a quantity of
cutting oil into a
small container
and position it near
the receiver end of
your workspace.
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I prefer to fully
strip the bolt,
including the
extractor in order
to have nothing in
the way.
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I wrap a patch
around a plastic
brush to clean all
debris from the
chamber.
LUBRICATE THE REAMER
EXTENSION ROD WELL
WITH CUTTING OIL.
INSERT THE ROD HALF
WAY INTO THE BARREL.
I USE A PLASTIC BRUSH DIPPED IN
THE CUTTING OIL TO APPLY COPIOUS
AMOUNTS OF OIL TO THE CHAMBER.
YOU CAN’T USE TOO MUCH CUTTING
OIL. MAKE A MESS, IT’S A
GOOD THING.
DIP THE REAMER INTO YOUR
OIL CONTAINER TO GET IT
FULLY COATED WITH
CUTTING OIL.
ATTACH THE BUSHING TO
THE BACK OF THE REAMER.
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Carefully insert the
lubricated reamer
and attached
bushing about half
way into the
chamber.
Notice how messy
this has become.
That’s perfect!
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While holding the
reamer in place, slowly
slide the extension arm
against it.
Turn the extension rod
slowly in a clockwise
direction to screw it on
the reamer.
The reamer will start to
turn once it’s fully
screwed on.
Stop!
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Slide the bolt
against the bushing
on the back of the
reamer.
Make sure it is flat
against the face of
the bolt inside the
outer ring of the
bolt face.
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VERY slowly slide the
bolt and reamer into the
chamber while
supporting the
extension rod on the
muzzle end until it
stops.
You don’t want to bang
the reamer against the
shoulder and leave a
nick to start with that
you’ll have to ream out.
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On a short
chambered new
barrel you should
expect to see this
when the reamer is
fully inserted.
DON”T push
down hard on the
bolt handle and
score the chamber
shoulder.
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While slowly turning
the extension handle
and reamer clockwise,
very lightly press down
and forward on the bolt
handle allowing the
reamer to slowly cut the
chamber.
You will see the bolt
handle and safety lug
begin to drop after a few
turns.
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When the bolt is about
half way closed slide it
back off the reamer and,
using the extension rod,
slowly slide the reamer
out of the chamber.
You will see metal
shavings on the reamer
from the reaming
operation.
REAMER REMOVAL
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Most reamers have a flat
to put a small wrench on
for removal.
Remove the bushing so
you don’t lose it.
Secure the reamer with
the wrench and turn the
extension rod counter
clockwise to unscrew it
from the rod. Don’t
drop the reamer on the
floor and damage it.
IN SOLVENT FIRST.
MAKE SURE YOU REMOVE
THE BUSHING FIRST AND
BLOW THE REAMER WITH AIR
TO REMOVE ANY METAL
SHAVINGS.
POUR SOLVENT DOWN THE
BARREL AND BLOW OUT WITH
AIR.
SWAB THE CHAMBER WITH A
PATCH WRAPPED AROUND A
BRUSH TO REMOVE ANY
REMAINING METAL DEBRIS.
RE-OIL THE CHAMBER.
OIL AND INSTALL THE
REAMER AND BUSHING.
MOVE THE BOLT AND REAMER
FORWARD CAREFULLY.
APPLY LIGHT FORWARD AND
DOWN PRESSURE ON THE BOLT
AND TURN THE ROD CLOCKWISE.
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At this point I
usually leave the bolt
closed and, using the
extension rod, press
the reamer/bushing
against the bolt and
take a couple of
turns on it to smooth
any rough spots.
It’s not required but
it’s just something I
do.
REMOVE AND CLEAN THE REAMER.
BE SURE TO REMOVE THE BUSHING
BEFORE BLOWING.
CLEAN OUT AND BLOW OUT THE
BARREL AGAIN AND SWAB THE
CHAMBER CLEAN AND DRY.
GO and NO-GO Checks
CLAMP THE BR BACK IN YOUR
PADDED VISE, INSERT THE GO GAGE.
WITH LIGHT FINGER PRESSURE
VERIFY THE BOLT WILL EASILY
CLOSE. IF NOT MORE REAMING WILL
BE REQUIRED.
INSERT THE NO-GO GAGE
THE BOLT SHOULD NOT
CLOSE ON THE NO-GO. THAT
MEANS YOU DID THIS RIGHT
YOU HAVE JUST INSTALLED
AND HEADSPACED A NEW
BARREL ON YOUR 1903A3. ALL
YOU HAVE LEFT TO DO IS PUT IT
BACK TOGETHER, SHOOT AND
ENJOY IT FOR MANY YEARS.