Although the following article does not specifically address a military
surplus rifle project, I felt it has appropriate content. In the spirit of
self-made firearm accessories I felt that a similar mount could be easily
adapted for several of the surplus rifles we shoot today, to use full-size
scopes. Also I have been planning for some time to address drilling and tapping
a scope mount on a rifle.
By R. Ted
Jeo and Mark Trope
I had not shot a 4 position
small-bore match for over 12 years when I started up again at the local indoor
league at the St. Croix-Hudson Gun club in Wisconsin in January of 2000.
I did not have the expensive
equipment that the other shooters had in my league, just an old Stevens 416 with
iron sights. The 416 worked for a while until the trigger gave out and
became erratic. Eventually, I traded the 416 for a CMP Harrington and Richardson
M-12 rifle, brand new with new Redfield Palma sights. I managed to get
quite respectable scores with this set up.
But then I noticed that my
eyes were not as good as when I was back in college and my scores started to
many target rifles of that earlier era, my H&R M-12 was equipped with the scope
blocks mounted in front of the receiver on the barrel. To help my ailing
scores I wanted to mount a scope on the rifle, so a teammate of mine lent me his
spare Unertl 20x target scope. Again, I was able to bring up my scores.
As the season ended that second year, I started looking into purchasing a Unertl
type of scope for my rifle…and nearly fainted at the price tag! 36X Unertl
scopes were selling for as much as $1,500.00. What to do? I could
have the receiver drilled and tapped for standard scope bases, but I did not
want to alter the original rifle configuration. Eventually, it led me on a
search via the Internet that ended up with me discovering Mark Trope.
a bench rest shooter, had designed a scope mount using one inch steel bar and
Tasco scope mounts that allowed him to attach a regular “modern” scope to his
H&R M-12 without any modification of the original rifle. The problem for me was
that his mount would put the scope high above the receiver (on the order of
several inches), which, of course, would be way too high for my 4 position
shooting. Over a period of several weeks we collaborated and came up with mount
design that could be used for position as well as bench rest shooting and was
easy to build. The main objectives we had was to use materials and tools that
are common to most shooters workbenches and not break the bank doing it. The
total cost for parts and any special tools was just under $30, well within my
cheap budget and many magnitudes less than the cost of any Unertl, Fecker, or
Lyman classic target scope. Just like those classic scopes, our base allows a
scope and base assembly to be moved from rifle to rifle without dismounting the
scope from the rings (Figure 1).
started out with just trying to find a suitable metal bar that would fit the
distance between the barrel mounts. We settled on ½ inch square mild steel
tubing that you can pick up at almost any hardware store for around $6. A
standard length of 36 inches is enough to build two scope mounts, or give you
more than enough to practice drilling and tapping. Of course, you will need to
make sure that it is square and straight which is not a problem as the tubing
does not bend easily. We also found the tubing to be light as well as strong.
A completed assembly with Weaver base, tube and Millett claws weighs only 7.9
ounces. Mounted to the ½ inch tubing will be a Weaver 63B scope base. We
selected this base because it very closely fits the ½ tubing width and is
designed to be used on a flat receiver and is average in height. The one thing
that we did not want to do is add too much height to the entire contraction.
Before you start the project, you should test fit your scope with rings to
determine if you have enough clearance for the scope objective. Both Mark and I
have built and used the scope mount on our H&R M-12 rifles using different
scopes and rings. He has a BSA Platinum 36 x 44mm and a Weaver 36 x 40mm and
uses Burris Signature Zee high rings. I also have a BSA Platinum scope as well
as a Simmons 6.5-20 x 40mm Mag 44 scope with Millett mid-height rings. We chose
our configurations for different reasons. Mark is rather tall in stature and
likes the height and strength of the Burris rings. I like the adjustability and
fact the Millett rings do not add unnecessary height. I just needed enough
height to clear the bell of the scope. There is probably an infinite
combination of scopes and rings that would work for this mount, as long as you
clear the bell of the scope. I also like the Millett windage adjustable rings
because it allows me to compensate for “not so perfect” workmanship when
mounting the ½ tube on to the rifle.
The first step in the
process is to determine how long of a tubing piece you will need for your
particular scope and rifle combination. To do this, you will to mount the scope
to the tubing and then mark where the barrel mounts meet the tubing. This way,
you can adjust for eye relief and also make sure that the tubing does not
interfere with the action of the rifle. To accomplish this measurement, you
will need to attach the Weaver 63B base to the tubing and then attach your scope
to that base. Before starting the step, cut the ½ inch tubing into two 18 inch
sections, this makes it easier to work with. Next, measure and mark, using a
Sharpie type marker pen, a centerline that runs from one end of the tubing for
about 8 inches or so (Figure 2).
the 63B base so that the rear end of the base is flush with the end of the
tubing. Align the holes in the mount with the centerline and,
a center punch (as shown in figure 3), mark at least two of the
holes where you will need to drill for mounting the 63B base to the tubing.
will need to use the #28 drill bit to make the correct sized holes for these
screws (figure 4).
Ideally, a drill press would be the
best tool to make the
holes; however, I have
found that if you are careful a hand drill will do the job fine.
is to drill the holes as perpendicular as possible (figure 5).
Use a few drops of oil to lubricate the bit as you drill.
the holes have been drilled, carefully clean them of metal shavings. Use
the 8-40 tap (figure 6), set
up your tap handle (figure 7).
few drops of oil to the hole/tap and carefully start to cut the threads by
turning the tap. As the metal is not so thick, it only takes a few turns to
accomplish the threading.
will feel the tap take hold and then it will turn very easily (as shown in
point, you have cut the threads into the tubing and you can back the tap out.
Be sure not to over cut the hole making it too big for the screws. Before you
try to mount the base, make sure you clean out the excess oil and any metal
shavings in the hole. If you leave the shavings you will ruin the thread
and the screw will not hold.
Attach the 63B to the tubing
and tighten the screws snuggly (as shown in figure 9). Mount the scope to the 63B base using
whatever Weaver style rings work for the scope. You can now use the scope
to determine eye relief and also locate where the barrel mounts meet the ½ inch
way to accomplish this is to rest the rifle on a table.
Place the tubing (with the scope mounted) such that it
rests squarely on the two barrel mounts of the rifle.
While kneeling down, try to get a good idea where the
scope should be in relation to your eye. Another way to
accomplish this task is to use the eye relief distance
as given by the manufacturer and use that to set the
distance from the scope to your eye. It needs only to
be an estimate as you will be able to move the scope
forwards and backwards for fine adjustment either
changing the position of the rings or moving the entire
mount on the scope mount blocks on the rifle. Make sure
that you also check that the tubing will not interfere
with the action of your rifle. Once you have a rough
idea where the correct eye relief lies, you will need to
mark where the tubing rests on the scope mount blocks.
Make the mark on the tubing where the middle of the
scope mount block is. Do this for both blocks on both
sides (figure 10).
marking the middle of the blocks, you will still have
about ½ inch of forward and backward adjustment for the
entire scope. Remove the scope from the 63B base before
you go on to the next step.
target scope mount uses modified Millett “claws”, the
same ones that are used on their adjustable windage
scope rings. As you look at them you will notice a tab
that sticks out just above the hole used for mounting (figure
11) . Normally, this tab
latches into the Millett scope ring, but you will need
to remove it so that it seats flush with the metal
can use either a metal file or a rotary style tool with
cutter wheel. Remove the tab piece from all four
“claws”. (as shown in figure 12)
the “claws” modified and ready to be mounted, the next
step is to mark, drill and tap the holes for the “claws”
on the metal tubing.
scope mount blocks used on the H&R M12 barrel require
that a hole for the modified “claws” to be drilled at
0.14 inches from the bottom of the
tubing (figure 13) . This
should work for most all barrel mounts on other target
rifles, such as the Winchester 52, BSA Martini,
Remington 37, 513 T, etc. Measure the location of each
of the four holes using a caliper and mark them. Using
the center punch, make a starting hole for the drill.
You will need to use the #31 bit for each hole, again,
using a few
drops of oil to help in drilling. Make sure that you
drill into the tubing as straight as possible if you are
using hand drill. Do not drill completely through both
sides of the tubing at each holding point.
Clean all the metal shavings from the holes and set up
your taps. Use the 6-48 tap and carefully cut the
threads for each hole using the same procedure as you
used to tap the holes for the 63B base. Again, use a
few drops of oil to help with this process. Be careful
not to over cut and enlarge the drilled hole or the
Millett screw will not fit. Once you have cut one hole,
clean out the metal shavings and oil and try one of the
Millett screws. It should start and snug up to the
metal tubing with ease. Continue cutting with the other
three holes and clean out any metal shavings and oil
that are in the holes before trying each Millett screw.
ahead and attach the tab-less “claws” to the metal
tubing and attach the scope to the 63B base. Attach the
entire device to your rifle and snugly tighten the
screws on the “claws”. You should again make sure that
the operation of the bolt is not impeded. If it is,
loosen the claws and slide the mount forward (figure
14). The scope is now ready to be
first thing you will want to do is make some coarse
windage adjustments using the four Millett “claws” on
the tube mount while bore sighting. We have found by
careful adjustment of the claws we can almost zero our
rifles with their use alone. This is as easy as
loosening a claw on one side and tightening it on the
opposite side. If you are using the adjustable windage
scope rings from Millett, you will also be able to move
the scope side to side on the 63B mount. It usually
only takes us 3 or 4 clicks of windage to finish
settling our shots in the X ring after a careful boring
sighting with the claw adjustment. You may also need to
adjust your eye relief by sliding the entire mount
forward or backward as needed. If you need to
drastically adjust the eye relief and you cannot slide
the scope using the scope rings, you can always remove
the device and drill new holes for the “claws” further
forward or backward. To completely finish the project
you may want to blue the bare steel tubing. A quick
polishing of the tube with 400 grit wet and dry paper
will allow it to take a nice cold blue.
side note, I have recently completed a custom x-course
stock by Elkridge and will be using this new stock and
scope combination in the upcoming season. Even though
it would seem that the rifle would be too tall to fit in
any off the shelf gun case, it does! I use a Plano
AirGlide case (model 1301) designed for a scoped rifle
or shotgun (figure 15). After
trimming down the foam pads a bit, there is enough room
for the scope to clear the lid. There is also enough
room left over in the case for such small items as front
hand stops, hook buttplates and mini bipods. I would
recommend this type of case because of its reduced
weight and locking features, and, of course, it is a
whole lot cheaper than a metal case.
older target and match rifles languish in gun cabinets
due to not having a scope to fit the barrel mounted
scope bases. It is understandable the owners of rifles
such as Winchester Model 52’s, Remington 37’s and
513T’s, BSA Matini’s, etc. have no desire to drill and
tap these classic match rifles. With our scope base,
virtually any of these rifles can be set up with short,
internally adjusted, modern rifle scopes by
repositioning the location of the “claws” on the mount.
Whatever your desire is, be it plinking, silhouettes,
position shooting or bench rest, dust off those classic
target rifles and mount a modern scope on them and get
out for some shooting fun!
What you’ll need for the project:
One ½ inch square mild steel tubing piece at least
18 inches long
Weaver 63B scope base with mounting screws
Four Weaver style “claws” from
Millett with mounting screws (6-48 thread)
Tools and Supplies:
Electric drill or drill press
Metal file or rotary tool with cutter wheel
Flat blade screwdriver
Hex wrench (5/32”)
Calipers and measuring tape
Oil (Tap oil preferred)
6-48 taper tap (drills, taps and handle are
available from Brownells)
8-40 taper tap
#28 drill bit
#31 drill bit
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