Debugging Mosin Nagant 1891/30 Rifles

Debugging Mosin Nagant 1891/30 Rifles
Excerpts from “Sport Shooting” by A.A. Yuryev, Moscow 1962
Debugging an Army model 1891/30 rifle requires that we properly mount the barrel to
the receiver in a stock, debug the trigger and adjust the sights so that they allow precise
correction.
For a battle rifle to group and be stable, we must first ensure that the barrel is operating
in conditions under which it will vibrate equally at each shot. Therefore, seating in the
stock must either be free, where the barrel does not touch the forend, or the barrel must
sit on three points - secured in the bed of the tail rotor, and the stop screw gland in the
forearm . Sports practice has shown that both methods are work well. However, in recent
years, the second method has received preferential distribution.
Loose fit is achieved by removing the barrel , scraping wood from the gutter in the
forearm and hand guard and filing the tip in the forearm ( Fig. 14).
The gap between the barrel and the gun needs to be 1 - 1.5 mm. A spent cartridge can be
used as a kind of chisel to scrape the gutter in the forearm. ( Fig. 15). The gap between
the barrel and the forearm is checked with a piece of paper folded twice or three times
and inserted between them (Fig. 16). In those cases when the gap between the barrel and
the gun is big and the assembled rifle is still touching the forearm, the stock should be
aligned with spacers of oiled paper or cardboard by placing them under the chamber or
receiver and layering them with the more on side or the other depending on where the
barrel hits the forearm ( Fig. 17).
A loose-fitting stock requires careful screening and selection. If the bed is made of
twisted wood, it is under the influence of moisture or excessive heat. During long
shooting the barrel will warp and the handguard touching the stock will severely affect
the accuracy of battle rifles . Therefore, finding that a stock is made of a wood that is
subject to significant warpage and leash, you must change it when debugging the rifle
barrel. Immediately put on a stock of walnut, for more reliable operation. The downside
to a loose fit in the trunk box is that any stock, from whatever type of wood it may be
made subject to greater or less warpage, can not fully guarantee the barrel without
landing to fit the forearm.
In the second method of planting box in the stock, " three points" we should also
remove an extra layer of wood from between the forearm gutters and the barrel and the
gap then filled under the upper forearm mounting ring 5-7 cm wide by winding the
barrel with oiled wool matter , or even better with felt ( Figure 18). The seal thickness
should be such to fill the gap between the barrel and the gun , at the same time it should
not be very tight . Application of this gland allows you to create equal conditions of
barrel vibration during firing and it protects the barrel from touching the forearm. Even
in some cases warping lodges in this connection at long shooting battle rifle becomes
much more stable. Furthermore, the seal prevents the penetration of foreign bodies into
the space between the barrel and forearm .
With this method of planting, a stock should be selected which is not subject to strong
warpage , as this is makes possible a certain deflection of the barrel, which will entail
change in the mean point of impact in the process of shooting and increased dispersion
of shots.
When debugging pay careful attention to proper bedding of the receiver. Without tilting
the bed next to the thickened part of the trunk under the rear chamber and tail, the
receiver should touch the wood with no distortion on most of these three surfaces
( Fig. 19). Especially you need to ensure that the back plane of the lugs is aligned tight
with the plane of the tunnel.
Strong recoil creates a significant inconvenience for sports shooting, so it should be
reduced. The fact that the material from which the stock was made - wood, has a certain
elasticity and is a good shock absorber, softens recoil. It is very important to make sure
that as much of the lodge ( the recoil system from in barrel to receiver) participates in
shock absorption . If the recoil of the Army rifle 1891/30 is transmitted from the trunk
bed only through the mounting points, then the recoil is normal , but if it goes to the tail
behind the receiver or if there is no gap for eyelets fixing the trigger, or run into the box ,
the rifle is very much "fight ." Therefore, a layer of wood must be removed for detection
of dents in the box at the tail of the receiver and eyelets for attaching the trigger
(Fig. 20) . In order for recoil to be normal and not impaired by vibration, there should
also be a gap between the stock and the magazine (Fig. 21) .
Debugging the Trigger
We must adjust and debug the trigger so that it will meet the following requirements:
the trigger must be securely held on the sear to avoid accidental, unsighted shots. If
pressing the trigger is not made until the end, then the trigger should vigorously return to
the forward position, the trigger m ust not have excessive tension, discharge, especially
with warning, must be clear and stable, and not change its character from shot to shot,
the discharge must have a constant tension, have no inhibitions due to local distortions
caused by incorrect fitting of parts and the presence of gaps, discharge must not have
“failures”, i.e. a sharp decrease ini eresistance of the trigger finger force at the time of
the failute to trigger sear, as this weapon will start at the most crucial moment of a shot.
Discharge without warning.
Clarity and precision is achieved by changing the form of the sear , it should be cut
down with a file from above and behind , as shown in Fig. 24 as well. For discharge that
is smooth , the top and rear faces of the sear should be polished to a mirror state (Fig.
24.6 ) . To create a short discharge or long pulls depends on the sear release , if you need
to do more short discharge , you need to reduce output of the sear, if , on the contrary ,
the shooter wants to use a long discharge, yield of the sear msut be to enlarged. In cases
where the sear engagement for cocked (insufficient and too easy discharge), you must
either bend the trigger spring ( Fig. 25a ), or increase the yield of the sear by sawing the
heels of the trigger spring ( Fig. 25.6 ) . However, the changing nature of the discharge
is not only achieved by treating the trigger spring , but appropriate treatment of the
trigger.
To make a short discharge, you need to change the shape of the projection in the slot of
the trigger , which is achieved by filing its upper bound in the gap (Fig. 26 , left). this be
very careful just to round off , and then fill the projection ( Fig. 26 , right).
Discharge with warning
This way to debug discharge was discovered and first introduced by honored Master of
Sports AN Bogdanov . Debugging and adjustment of sear warning requires the same
refinement and trigger spring and sear as the discharge without warning . The difference
lies only in the debugging in a different character of processing of the upper bound gap
trigger.
To make the discharge with a warning otherwise need to somewhat differently polish the
upper face of the gap ( Fig. 27, left) , and then drill a release hook with a 2 mm diameter
drill bit so that a slit is formed in the sharp edge of the projection ( Fig. 27 , center } . To
aoid breaking the drill, it is necessary to insert and adjust the pre- slit in the metal insert
and then make a through bore . Protrusions are formed in the slot from drilling. Very
carefully round them off a fine file (needle file). With this method of debugging tension
is lowering by treatment of the trigger spring . Depending on where drilling it can make
the discharge with different pre- swing - short or long stroke (Fig. 27 , right).
Achieving smooth discharge warning requires careful polishing to a mirror trigger spring
in contact with her lip in the slot (Fig. 28) .
In order for the rifle trigger mechanism to not change tension from shot to shot, to be
clear and reliable, we must pay attention to the processing of parts and the fact that the
friction surfaces are well polished and the whole plane adjoined to each other. In
addition, the trigger should sit tight in the eyes of the receiver and not have any
pitching , so that when you press the trigger and its movement is not straight.