This document describes a patent for an improved rear rifle sight. The sight has adjustable scales to show the position of the sighting aperture. The scales can be moved independently of the adjusting mechanism and locked into the zero position after the sight has been calibrated to the rifle. This allows the rifleman to accurately set the zero without having to mentally account for the offset introduced during calibration.

1. * GB780136 (A)
Description: GB780136 (A) ? 1957-07-31
Improvements in or relating to rifle rear sights
Description of GB780136 (A)
PATENT SPECIFICATION
Date of Application and filing Complete Specification: June 27, 1955.
780,136 No. 18531/55.
Application made in New Zealand on July 2, 1954.
Complete Specification Published: July 31, 1957.
Index at acceptance:-Class 119, A11A(2:4:5:8:12:14), A11C8.
International Classification:-FO7h.
COMPLETE SPECIFICATION
Improvements in or relating to Rifle Rear Sights I, DANIEL ROBERTSON,
of 8, Raroa Road, Lower Hutt, in the Dominion of New Zealand, a
British subject and New Zealand citizen, do hereby declare the
invention, for which I pray that a patent may be granted to me, and
the method by which it is to be performed, to be particularly
described in and by the following statement:-
This invention relates to rear rifle sights and is particularly though
not solely applicable to rifles used for target rifle shooting.
In the rear rifle sights as at present used for target rifle shooting,
a sight is usually provided in which a rotatable member such as a nut
is used to rotate a screw which in turn moves a sighting aperture or
notch, movement in the horizontal plane being effected to allow for
wind deflection and movement in the vertical plane being effected to
allow 20for changes in range.
In such rifle sights as at present constructed, when a rifleman is
calibrating his sight relative to his rifle he must shoot at a zero
target arranged at a known distance from his 25shooting position and
by setting his sight to the required elevation, a shot pattern can be
provided which will indicate as to whether or not the rifle and the
sight are matched to each other. If a group of shots are pat30terned
for example at 1 o'clock using the usual clock indicating system, then
the rifleman must adjust his sights so as to bring his shooting

2. downwardly and to the left. Thus with present rifles when the rifle is
shooting correctly the sight will be set incorrectly and the rifleman
must retain in his memory the setting necessary to give accurate
shooting.
However, under certain shooting conditions, e.g. where the wind may be
changing rapidly, the difficulties raised by adding or subtracting
zeroing corrections may lose many points for a rifleman.
It is therefore an object of the present invention to provide a rear
rifle sight which will obviate or minimise the above disadvantages.
[Price 3/6] Accordingly in one aspect the invention consists in a rear
rifle sight having a sighting aperture or notch the position of which
is adjustable by adjusting means forming part of the sight, and having
a scale or scales to 50 show the position of the sighting aperture or
notch, characterised in that said scale or scales are movable
independently of said adjusting means and have releasable locking
means to lock said scale or scales in position, 55 so that in use when
the sight has. been accurately set relative to the rifle on which it
is mounted, said scale or scales may be freed from the locked
position, moved to show zero and then fixed in that position. 60 In a
further aspect the invention consists in a rotatable member for use in
a rear rifle sight for the purpose of moving a sighting aperture or
notch, said rotatable member having a scale or scales associated with
it 65 and being characterized in that said scale or scales are movable
independently of said rotatable member and are adapted to be locked
thereto, so that in use when a sight incorporating said rotatable
member has been accurately set relative to the rifle on which it is
mounted, said scale or scale may be freed from the locked position,
moved to show zero, and then fixed in that position.
One preferred form of the invention will 75 now be described with
reference to the accompanying drawings in which, Fig. 1 is a front
elevation of a sight constructed according to the invention; Fig. 2 is
a plan view of Fig. 1 and 80 Fig. 3 is a cross section on the line
3-3.
Fig. 2.
Referring to the drawings, a mounting block 1 is provided which is
suitably constructed to fit any of the usual types of rifles 85 -used
for target shooting. A vertical slotted bar 2 is fixed to the mounting
block 1 by a screw 3. A channel 4 in the bar 2 and a corresponding key
5 in the block 1 assures somewhat substantial definition as to the
position 90 780,136 of the bar 2 relative to the block 1. A horizontal
bar 6 is slidably mounted within the slot 7 of the horizontal or
elevation bar to be adjusted 5a screw 8 is provided. The screw 8
presses against the end 9 of the slot 7 and is threaded in the
horizontal bar 6.

3. Rotation of this screw is effected by means of a rotating member
comprising a nut 13.
The upper end of the slot 7 is closed off by a collar 10 attached to
the vertical bar 2 by screws 11. The diameter of the screw 8 is
diminished and a second screw 12 is provided. The nut 13 is screwed on
the screw 1512 and is locked in position by a lock nut 14 fitting in a
counter-bore 15 in the nut 13.
The edge 13b of this nut 13 is knurled or a finger grip is otherwise
provided thereon.
A loose calibrated shell or sleeve 17 has a 20shoulder 18 which
engages the collar 10. The shell 17 is provided with calibration
markings 19 and 20-one set running from 0 to in one direction and the
other set running from 0 to 4 in the opposite direction. Shell 2517 is
adapted to be adjustably attached to the nut 13 by means of a grub
screw 21 which may be screwed so as to frictionally engage the nut 13.
If desired radial depressions may be cut in the face 22 of the nut 13
and a spring loaded ball 23 provided in the collar 10 which will
enable the radial depressions to be engaged so as to give a positive
location of the nut 13 at positions corresponding to the positioning
of the radial de35pressions 22. Ten such lines may be provided. The
index markings 19 move relative to a zero line 24 which may be
indicated or which alternatively may simply be one of the edges 25 of
the vertical bar 2.
Also fixed to the vertical bar 2 is a scale 26 fastened by screws 27
which pass through slots 28 in the scale 26 and this scale has
calibrations 29 which indicate hundreds of yards. On the elevation bar
6 there is provided a zero mark 30. Movement of the height bar 6 by
rotation of the nut 13 and consequently the screw 8 will move the zero
mark relative to the scale marks 29.
To provide deflection adjusting means the elevation bar 6 is provided
with a slight aperture block 31 having an aperture 32 into which any
of the known types of optical apertures may be screwed. The sight
block 31 is movable to the left and to the right by a screw 8a turned
by a nut 13a, the construction of this screw and nut being similar to
the construction of the screw and nut above described. In Figs. 1 to 3
of the accompanying drawings the nut 13a and its associated 60parts
are given similar references as the nut 13 with the addition of the
suffix "a" thereto.
Accordingly rotation of the nut 13a will move the aperture block
either to left or to right of the central position. The aperture
65block is provided with scale markings 33 and a zero strip 34 is
fastened to the bar 6 by a screw 35 passing through a slot 36. The
width of the strip 34 is made the same as the width of the sighting
block 31 and left or righlit deflection is read off on the scale 70 33

4. by using either one edge or the other of the strip 34 as a zero line.
By the provision of the slot 36 the strip 34 is made adjustable as
will be described further later.
The use of the invention is as follows. By 75 the use of a standard
zero target sheet on a standard length range the rifleman adjusts his
sights to zero deflection and for example sets the height scale to 300
yards. He then fires a group of shots. It will be assumed 80 that
these shots land at about 1 o'clock on the target. This indicates that
he must bring his shooting downwardly and to the left. Accordingly he
adjusts his sight accordingly by rotating the nut 13 to move the bar
685 away from the rifle and he adjusts his sight block 31 to bring the
sight block to the right.
He then fires again and by repeating this procedure hlie sets the
sighlt to the rifle. When this is completed and the sight is
accurately set 90 relative to the rifle. both nut 13 and the nut 13a
may be for example. a half revolution away from the respective zero
positions. The rifleman then releases the shells 17 17a from their
association with the nuts 13 and 13a95 rotates the shells free of the
nuts without altering the setting of the nuts and consequently the
screws 8 and 8a and sets the zero position of the scales in their
correct positions relative to the zero lines 24 and 24a. He then 100
refixes the shells to the nuts 13 and 13a and if necessary he adjusts
the height scale 26 and the strip 34 so that the zero lines of these
coincide with the required indicating lines on the scales. The sight
then accurately 105 set up to the particular rifle and the rifleman
may set his wind and height knowing that he is starting from a correct
zero. The advantages of this are many, particularly in target rifle
shooting for which the present l10 invention is particularly
applicable.
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