ACCURIZING THE
STOCK BEDDING
I will break down the issue of stock bedding
into two parts, for the curious and the serious. Essentially the two parts are
standard bedding and for the competitor, center bearing stocking. It is important
that the steps be followed in the correct order so that the completed rifle
will have the correct pressures at the correct places.
After reading this page, check Stock Bedding Page 2. This page offers actual range target
results of the effects on accuracy the stock bedding and center bedding has on
a Lee Enfield No4 Mk2. See for yourself the changes.
Standard Stock Bedding - Military Specs
The fore-end must fit tightly at the rear
end, between the sear lugs and the buttsocket of the body. See figures 1A,
(a) and (b).
A good bearing must be obtained on the body surfaces, around the hole for the
front trigger guard screw and along the narrow ledge on each side of the
magazine opening. Extending for a distance of no less than 1-1/2 inches to the
rear of the front trigger guard screw hole. It is important that this bearing
is even throughout its surface and that the fore-end is clear on either side of
the barrel socket of the body. See figure 1B.
There must be a good bearing of the reinforce, extending for it's entire length
and not less than one third of the reinforce seating in width. It is important
that this bearing is in the center of the reinforce, the sides being entirely
clear of the barrel. See figure 1C.
If a fore-end is encountered that is low at the reinforce and difficulty is
experienced obtaining a bearing, two remedies are at hand to float out the
reinforce.
Wood Patch Method
Chisel out the existing reinforce, level with the body seating with a minimum
width of 3/4 inch. Under cut the sides of the recess with a slightly decreasing
taper towards the front, to form a dovetail seating for a patch. Fashion a
patch from similar wood with the grain running front to rear and shape it to
give a snug drive fit in the dovetail recess. Ensure the patch is of sufficient
thickness to permit floating it out to give the bearing described above. Glue
the patch into position and allow to set. Once set, file and sand the patch to
form the new correct reinforce seating.
Fiberglass Method (modern)
As with the wood patch method, chisel out the existing reinforce level with the
body seating. Rough the surface sufficiently to provide for good adhesion of
the fiberglass. Using body dummy (plasticine) build a dam at the front and rear
of the reinforce area and fill this area with an appropriate fiberglass
mixture. Seat the rifle action and barrel back into the fore end and secure as
normal. Let the glass set. It is important to remember to coat the metal
surfaces with a release agent so that it may be removed once the glass has set
without disturbing it. Once set, remove the barrel and action and sand down the
sides of the new fiberglass reinforce to form the correct seating.
The muzzle end of the barrel must bear for the full length, and be in the
center of the raised seating at the front end of the fore-end. If off center,
adjust the fit of the rear lugs, either left or right to correct the muzzle
position to center. See figure 1(a) & (b). There must be a clearance
between the barrel and the fore end on either side of not less than
0.02-inches. See figure 1D. The weight required to raise the barrel from this
seating should be between 3 and 10 lbs. To test this pressure, use a 0.003-inch
feeler gauge. Set it between the barrel and fore end and using a fish scale
gently lift the barrel until the gauge will pull out, read the scale. If the
weight is below 3 lbs., the bearing at the reinforce seating should be lowered
slightly and the collar for the front trigger guard screw shortened as necessary.
The barrel must be entirely free from influence of the fore end except at the
points specified. The clearance between the fore end and the barrel, from
reinforce bearing to muzzle bearing, should be a little more than 0.05-inches.
The hand guards must also be clear of the barrel by the same amount, except at
the muzzle where the clearance may be less provided the barrel is free. Care
must be taken that the rivets and metal strengthening pieces in the hand guards
are well clear of the barrel.
Figure
1
Competition Stock Bedding - Center Bearing
Note: Because the following
procedures involves alterations to the rifles fore-end that are NOT reversible,
I would suggest anyone trying these bedding procedures acquire a second
fore-end, so as not to alter or destroy the originality of the rifle.
The details in this section are laid out in two stages and it is important to
follow the procedures in order of sequence so that the finished job will have
the correct pressure at the center bearing.
Stage One - Stock Bedding
To begin, make sure the rifle is bedded as per the military standard,
having 3-10 lbs. downward pressure at the muzzle. To get this pressure, the
rear surface of the fore-end and sear lugs have to be shimmed up with arborite,
use shim stock of .025-inch thickness, or any similar hard fiber material of
this thickness. With this shim stock in place, fitting of the reinforce and
under the body is necessary to get the body level and the muzzle pressure
correct. Check to ensure the barrel is centered in the fore-end. If necessary
file the shims to move the barrel left or right. See figure 1(a) & (b).
When this has been completed, the body and action tight, the barrel true in the
center of the fore-end, stage one is finished.
Stage Two - Center Bedding
Stage two is the fitting of the center bearing at the middle band. See figure
2. This center bearing can be fitted, either with a hardwood wood block or
with fiberglass. The hardwood block can be difficult to make without the proper
equipment, but it can be attempted by hand cutting. For the shape and size, see
figure 3. The groove in the block is hand-fitted to the barrel; it will
bear at the 10-1/2 inch point. Get this fit by putting sandpaper on the barrel,
towards the muzzle, where the barrel will be a bit smaller. By selecting the
correct point, the block will get a good radius fit at the center-bearing
point. Check the fit with lamp black and oil and keep sanding until a 100% fit
is achieved at the center-bearing point.
With the fore-end, a 1/8-inch recess is cut into the fore-end at the center
band. See figure 4. Adjust the center-bearing block until it fits freely
into the recess. Height is not a concern yet. Put lamp black at the barrel
bearing point; assemble the rifle with the block in its bearing recess
(unglued).
With the action screw tight, check the height of the barrel and its alignment
in the center of the fore-end. To get the barrel lower, and level, take the
wood from the base of the block; don't touch the radius fit of the groove. To
center the barrel a small amount may have to come off the side of the block.
With the barrel at the correct height, and true in the fore-end, the block 100%
in contact with the barrel, glue the block in place, assemble the rifle and
tighten up the main body screw.
The center bearing can also be made out of fiberglass with excellent results.
With this method, the barrel must be held up from the fore end for the required
barrel clearance. Place a shim ahead of the center-bearing point, to raise the
barrel about 1/8-inch. Free the fore-end and hold the barrel true in the center
of the fore end. With this in place, the required amount of fiberglass is put
in at the center band. When the glass is set, the temporary shim is removed.
With both types of bearings, the pressure should be from 12 to 14 lbs. This can
be checked by putting a thin metal test shim (.003-inch) under the barrel at
the bearing point. Raise the muzzle with a fish scale and note its reading when
the shim can be slid out with a gentle pull.
From here the rifle should be test fired to determine its group size before
proceeding to the next stage.
Figure 2
Figure
3
Figure
4
Stage 3 - Muzzle Shimming (Barrel Packing)
This stage may or may not be needed; I have used this procedure for my own
barrel packing experiment and have found it successful.
This method requires that the muzzle be shimmed up with cork, about .010-inch
higher than it's free position. To do this, remove both the front and rear hand
guards only and measure the free position of the barrel muzzle. See figure 5.
The measurements given in the figure are for example only, as the readings on
all rifles will differ.
To calculate how much shimming is needed to raise the muzzle .010-inch, press
the barrel down to the wood and take a second measurement.
As an example - if the free muzzle reading was 1.350-inch and when pressed down
to the wood it was 1.290-inch, you would know that the space under the barrel
muzzle is .060-inch. To this add the .010-inch lift needed, so the overall shim
thickness needed will be .070-inch.
If the space is excessive under the muzzle, it is a good idea to build up the
front with fiberglass. This can be done by putting a metal shim about .012-inch
thinner than the cork shim around the barrel, at the bearing point, before
filling up the muzzle bearing with fiberglass. When the tin shim is removed you
will have the correct clearance for the cork shim. See figure 6.
When the muzzle shimming is complete and the rifle is assembled with the main
body screw tight. The muzzle will read about .010-inch higher than it did in
the free position. In the example it would now read 1.360-inch. At this same
time the muzzle pressure is checked and should require 4-6 lbs. effort to lift
it from the front bearing. This pressure will not be sufficient to change the
center bearing pressure, which was set at 12-14 lbs.
With all this completed it is now time to fit the hand guards. First the rear
hand guard is fitted with a piece of rubber gasket (I prefer neoprene rubber
because of its resistance to heat and its resilience to crushing over time)
about 1x1-inch square. This is placed in the hand guard just over the center
bearing. Its thickness adjusted so that there will be about .010-inch gap
between the hand guard and the fore end to be pressed down by the outer metal
center band. If there is too much packing the outer band will not close or the
band screw will not meet. See figure 7. Next comes the front hand guard.
In the front hand guard, a piece of cork or rubber is placed in line with the
lower bearing. Have about .005 to .008-inch space between the hand guard and
fore end before the front metal band is screwed in place. Once again if too
much packing is used, the front metal band is hard to fit.
The final hand guard fitting involves checking that the metal band grooves at
the center are even, otherwise, when the band is tightened it will pull the
hand guards to one side. See figure 8.
Notes
This stocking procedure should improve the Lee's grouping at the 100 to 600-700
yard ranges. It was originally designed for the 7.62mm NATO converted
One cannot begin to fathom the past conditions that a particular rifle has
seen, was it soaked in the marshes of
Figure
5
Figure 6
Figure
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Figure
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