Rifle, No. 4, .303 and 7.62 MM Issue 3-5 Nov 54

1. The No. 4 rifle is a development of the No. 1 rifle, redesigned for mass production. The action arid the magazine systems remain the same. Except that the barrel protrudes approximately 3-in beyond the stock and the change in location of the backsight, the external appearance is similar to the No. 1.

2. The improvements in the No. 4 rifle over the previous service rifles are:

(a) An aperture backsight is mounted on the rear of the body giving a considerable lncrense in the sight radius

(b) The barrel is heavier, making it possible to omit the barrel repositioning components which are a feature of the No. 1 rifle.

(d) The extension of the bolt head is grooves instead of hooked and the body has a corresponding undercut ledge to serve as the bolt head guide, Bolt heads are supplied in four different lengths to facilitate the adjustment of the cartridge headspace.

(e) The stock bolt plate (keeper plate) normally fitted to the No. 1 rifle, has been omitted thus allowing the removal of the butt without first removing the fore-end. A spring washer is provided as a locking medium for the stock bolt.

(f) The bayonet is fixed directly to the barrel and is the short spike type.

3. Bolt heads of Mk I rifle are retained in engagement with a lip on the right side of the body; the bolt head is released by functioning a catch located just forward of the right recoil shoulder on the body. The catch must be depressed to assemble the bolt to the body or when removing it (this catch is omitted on the Mk 1 *), the bolt bead being turned over and through a small cut-away portion in the rib on the right side of the body. The following types of barrels may be encountered:

Mk 1-5 groove barrel
Mk 2-2 groove barrel
Mk 4-6 groove barrel

4. Telescopic rifles are produced from and are generally similar to those described in the preceding paragraphs, but in addition are provided with a bracket to which a telescopic sight is attached; a cheek rest is also fitted to the butt.

5. For ease of identification the various marks of backsights are described hereunder:

Mk 1: A leaf backsight machined from solid stock. Adjustment of the aperture slide is by a worm screw. A clicker arrangement is provided, giving ranges from 200 to 1300 yd in increments of 25 yd.

Mk 2: Dual fixed range aperture sight. Apertures are for 300 yd with bayonet fixed, and 600 yd without bayonet.

Mk 3: A leaf backsight manufactured from steel pressings. The adjustment of the aperture slide is retained at the various range settings by a spring loaded catch. The ranges are from 200 to 1300 yd in increments of 100 yd. The slide has been declared obsolescent owing to the extreme liability of the slide -retaining catch becoming damaged. The backsight consists of the following components:

Leaf, backsight, Mk 2 (Cdn pattern)	Spring, catch, backsight, Mk 2 (Cdn pattern)
Slide, backsight, .Mk 2 (Cdn pattern)	Pin, catch, backsight, Mk 1 or 2
Catch, backsight, Mk 2 (Cdn pattern)	Pin, stop backsight

Mk 4 Similar to the Mk.3 assembly but with a redesigned slide retaining catch and other minor differences. The catch is curved inwards towards the leaf, rendering it less liable to damage. The backsight consists of the following components:

Leaf, backsight, Mk 3 (Cdn pattern)	Spring, catch, Mk 2 (Cdn pattern)
Slide, backsight, .Mk 3 (Cdn pattern)	Pin, catch, Mk 3
Catch, backsight, Mk 3 (Cdn pattern)	Pin, stop

NOTE: The marks appearing on the components apply to the components and not to the assembly.

6. All components of the Mk 3 and the Mk 4 are interchangeable, with the exception of the catch, backsight, Mk 3.

7. The Leaf backsight Mk 3 differs from the Mk 2 in that the holes drilled for the pin stop backsight are drilled in the opposite sides of the leaf. The pin,assembled to the Mk 2 protrudes on the right side. The pin, assembled to the Mk 3 protrudes on the left side. The leaf Mk 3 was introduced to prevent the pin from interfering with the operator’s fingers, or the catch backsight when the slide is pushed to the top of the leaf . A quantity of the leaves Mk 3 may be found in the field erroneously stamped Mk 2. Therefore, all leaves Mk 2 will be examined prior to assembly to ascertain whether they are Mk 2 or 3. This can be determined by inspecting the holes drilled In the leaf for the stop pin. If the leaf is Mk 3, the smaller hole will be in the right side of the leaf; if Mk 2, in the left side.

8. The Slide backsight Mk 3 differs from the Mk2 in that a cut has been made in the right hand side of the Mk 3 to allow clearance to depress the catch Mk 3 to a point where it can disengage from the slot in the leaf, A quantity of slides Mk 3 may be found in the field erroneously stamped Mk 2, Therefore, all slides Mk 2 will be examined prior to assembly to ascertain whether they are Mk 2 or 3. This can be determined by inspecting the right side of the slide, if the slide is Mk 3, the right hand side of the slide will have a portion cut away at the top to provide a clearance for the catch Mk 3; if Mk 2 the right side will not be cut other than for that slot through which the catch operates.

9. The Catch backsight Mk 3 differs from the Mk 2 in that the Mk 3 is curved and the Mk 2 is straight. The Mk 3 was introduced to eliminate the possibility of the catch snagging on wires, tree branches, equipment, etc. This is the only component that is not interchangeable on either sight, If assembled with a slide Mk 2 the curved end of the catch Mk 3 will contact the slide, and t. will not be possible to depress the catch far enough to disengage the point from the slot in the leaf,

10. All other components are identical and interchangeable.

END

Issue 3-5 Nov 54