Tuning MP-512. Upgrade of air rifle MP-512

The Russian air rifle MP-512, which is popularly known as "Murka", occupies a leading position in its class in the domestic market. Like many other Russian-made guns, it has some flaws. Most of them are eliminated with a simple file. Today we will learn how to improve the characteristics of the rifle MP-512. The upgrade will concern the most common, basic version of the weapon, as the modifications of "Elegant" and "New Design" have their own personal characteristics.

a brief description of

The airborne MP-512 is manufactured since 1998. It became popular due to the low price, relatively good characteristics, simplicity of the device and simplicity of upgrade. Another distinguishing feature of "Murka" is a large safety margin, which also contributes to modernization. Among the shortcomings of weapons can be noted: instability of quality (each instance has its own problems), a strong return (especially after completion), uncontrolled descent. However, this is quite normal, considering how much is MP-512. The price depends on the modification and materials of the bed. It fluctuates in the range of 3-5 thousand rubles. The bed for the MP-512 can be plastic or wooden. Naturally, the wooden is more expensive. The sight for MP-512 is attached to the swallowtail. The rifle is used mainly for training and entertaining shooting. It easily lends itself to modernization, which opens the prospect of its use for hunting.

Main settings:

1. Type of construction - spring-piston.
2. The trunk is steel, threaded (6 rifling).
3. Caliber - 4,5 mm.
4. Type bullets - lead.
5. Weight - 2,8 kg.
6. The number of charges is 1.
7. Basic sighting devices are a crescent and a fly;

Well, now we turn to the modernization of the rifle. Let's start with increasing accuracy.

Platoon

Tuning MP-512 begins with the completion of the platoon. Due to the wrong angle of the thrust rod and the piston, the latter can pick up the cylinder. The angle must be changed in such a way that the thrust during cocking pushes the piston slightly downward. Therefore, the plane of the hook should be turned 5 degrees.

Soft descent

To the MP-512 gun had a softer descent it is necessary:

1. Correct the angle of the piston hitch with the sear.
2. Adjust the trigger angle of the trigger.
3. Treat the contacting surfaces of the piston and the shept. It's about grinding and polishing.
4. Treat the contact surfaces of the sear and the trigger in the same way.
5. Check the surface of the whisper axis for burrs. If they are, you need to process the axis.

First of all, the engagement between the piston and the sear is corrected. In unprocessed rifles, the piston transmits a torque to the searcheth, a significant part of which is transmitted to the trigger mechanism. This needs to be corrected. The perpendicular is drawn on the sear, which must be moved 2-3 degrees to the side.

Then the trigger of the trigger is processed (SC). At the factory guns, the SC shoulder has an incorrect angle. The radius from the end of the ledge to the axis of rotation is greater than the radius from the base to the axis. This leads to the fact that when you press the SK, the shooter acts on the sear in the direction of the larger hook with the piston against the force of the spring. To solve this task is very easy - you just need to straighten the shelves of the whisper. Processing begins with a file. Then you need to work skins. And the final debugging is carried out with the help of GOI paste. It should be noted that the faces of the descent must necessarily be sharp.

The manipulations described above lead to the fact that the descent force drops from 2-3.5 kg, declared in the passport, to 0.4-0.5 kg.

Short descent

You can make the descent shorter in two ways. First, you can put a transverse pin / screw, which will limit the movement of the trigger forward when cocked. In this case, the length of the hooking of the ledge of the hook with the sear is reduced. Secondly, you can simply reduce the length of the SC shoulder. The drawback of this method is its irreversibility.

The failure of the descent

The failure of the SC is called its idling after the failure of the whisper. To get rid of the failure, you need to install a suitable cylinder in the trigger spring. Usually use a piece of the rod from the gel pen.

Chamfer Chamfer

Many arrows complain that the MP-512 air has a poor-quality factory facet of the muzzle. As a consequence, the pellet at the time of the shot comes off the notch simultaneously, which leads to a violation of its trajectory. As practice shows, on the MP-512 shotguns, which we consider to be upgrading, the chamfer is not very beautiful, but even. Therefore, it should be modified only if you are sure that it is necessary. Sometimes the manufacturer pinches the barrel with knurled under the front sight. In this case, it is necessary to cut the trunk, to renew the chamfer, and sometimes even to cut a new thread.

For those who nevertheless decided to refine the muzzle in their rifle, consider one of the simplest ways of this responsible operation. So, to refine the chamfer we need:

1. Trunk.
2. Pulka.
3. Vata.
4. A ball with a diameter of 5-15 mm (the bearing will fit well).
5. Abrasive of different fractions.

The first thing you need to fix the barrel upright, muzzle up. From the muzzle to the trunk you need to shove a bullet first, then a piece of cotton wool. Wadding is necessary so that the abrasive does not get into the main part of the barrel. Then a little abrasive is poured into the barrel, so that a small slide is formed. A ball is laid on it. It is desirable that it was steel. Now a chamfer is made by rotational movements with light pressure. Rolling on the muzzle, the ball removes excess metal from the abrasive. After a while you will see how the chamfer gets a more accurate outline. It remains only to push the bullet with cotton wool from the trunk and several times to clean it with a new cotton wool.

The ball can be rotated either manually or with a drill. To do this, you need a tube like a rod from the handle.

Snout

For more accurate and balanced shooting, guns are often heavier with a bumper, and the MP-512 pneumatic is no exception. The weight of the blower can be from 300 to 400 grams. He is selected experimentally - on the gun put on different puffers until you get a good balance. It is desirable that in the end the weight of the rifle does not exceed 3.5 kg.

On this, we finish operations to improve the accuracy of the rifle. If everything is done correctly, then using the above tips, you can bring the accuracy of shooting to 10 mm from a distance of 25 m. Tuning MP-512 is not finished yet, because you also need to take care of its power.

Back boring

The backstop in this case is called the trigger box. To strengthen the spring of the MP-512 (to put a more powerful and long), you need to increase the recess in the back to about 30 mm. It is important that after this operation the bottom remains flat. Boring is made by a cutter. If in your arsenal there is only a drill with a tip angle of 120 degrees, then under the spring you will need to put something like a flat washer. For these purposes, a good coin. It is possible and not to bend back with a new spring, but then it will have to be pruned.

The weight of the piston

The rifle piston usually needs additional weighting. To do this, it simply installs a weighting agent. The latter should weigh about 150 bullets, which you shoot. Weighting agent can be purchased on the Internet or ordered from a turner. The MP-512 rifle sometimes has a special protrusion on the bottom of the piston, which neutralizes the unevenness of the spring (no matter how neatly the spring is cut off, the last coil protrudes). Because of the protrusion on the bottom of the piston after installing the weighting agent, there may be a skew, which adversely affects the operation of the rifle. Therefore, if a protrusion is detected in your weapon, before installing the weighting agent, it must be eliminated.

There are three ways to do this. The right version is the easiest - to buy a piston without a protrusion. Its price is about 250-300 rubles. The second option is more difficult - to grind the ledge on the lathe. The third option is the most unusual - to the bottom of the piston to bitumen or any other thick mastic, you need to glue the washer, which will even out the bottom. The weighting agent will tighten it, and the mastic will fix firmly. A coin of suitable size can act as a puck.

The spring that worked with the piston, at the bottom of which there is a ledge, is usually deformed. It needs to be leveled. You can do it with a simple file. The ends of the spring must be ground so that they become flat. It is advisable to do the same from the other end of the spring, which rests against the trigger box.

Bypass opening

For better performance of the rifle, the diameter of the bypass opening is reduced. This is done with a special sleeve. It is inserted into the rubber bypass gasket. A bushing, as well as a weighting agent, can be bought or ordered from a turner. To reduce the diameter of the bypass opening, a piece of the gel stick rod is also used. To the flow of air does not push it out, at one end you need to make a bonnet.

Cuff

Tuning MP-512 also involves the development of the cuff. Before talking about how this is done, it is worth recalling the theoretical aspect of its work. The cuff has static and dynamic friction. The first one we feel by moving it with our hands. And the second occurs during the shot, when the cuff is bursting with pressure. The latter phenomenon is called obturation.

Because of the obturation, the process of the shot is inhibited, so the groove is poured. However, a small obturation is still necessary, as it strengthens the compaction and contributes to less air loss, which leads to increased compression.

Thus, our task is to bring dynamic friction to a minimum, without compromising compression. The lower the compression, the higher the peak pressure, which at the time of the impact of gases on the bullet falls, which leads to a loss of speed of the bullet. And if the dynamic friction of the cuff is too high, some of the energy of the spring is lost, just like the pressure in the compressor, which also leads to a loss of speed. So that everything works well, you need to find a middle ground.

It is worth noting that if the piston and the cuff fall into the cylinder, this does not mean that the compression will be weak. After all, during the shot, the same obturation helps to seal the system. Also do not worry about the fact that compression lasts no more than 10 seconds - this is quite enough.

Check the compression is quite simple. Between the bypass and breech should be clamped rectangular plastic liner. If everything is in order, then during the shot the piston will not touch the bottom of the cylinder, and when opening the trunk there will be a characteristic cotton. If the shot hears a hiss, then the bypass is not tight.

Now you can start pouring the cuff. First of all you need to cut off the barbs, if any. After that, the front part of the cuff groove is covered with sealant. Here you need to make sure that air bubbles do not form. Then you need to wipe off excess sealant with a cloth and slide your finger along the seam to form a shallow groove. It should have a semicircular profile and not be deeper than 1 mm. Then the rear groove is covered up to the top. Now you can put the cuff on the piston, insert the piston into the cylinder and leave it all for 12 hours to dry out. The second cuff is poured and dried separately. In the front groove of the third one, you need to put an elastic band for money before pouring. The result is 3 cuffs with different diameters and static friction. In this case, they have no dead volume, and dynamic friction is much less than before tuning.

When the cuffs are dry, you can proceed with the assembly process. The piston and cuff should be lightly lubricated. It is important to make sure that the grease does not get on the front side of the cuff. The weighting agent is put in place, and everything is neatly assembled. Now we need to check with which cuff the rifle will be better to shoot. A chronograph is needed here.

The breech of the trunk

The official part of the "fresh" rifle smoothly goes into the rifling, which entails a slight bullet-pulling force. It can be fixed.

The first thing to do is to carve the pig through the regular thread of the trunk. Then, instead of the deadbolt (the wedge that holds the trunk closed), the shank of the 9-millimeter drill is put. After fixing the pig, you need to hit the drill with a heavy hammer. Due to this, the barrel must go beyond the coupling for one and a half to two centimeters.

Then you need to saw off the protruding part and align a breech using a wide flat file. Periodically, you need to attach the barrel to check the position of the clutch relative to the compressor. Then, after winding the 600-th skin on the file, it is necessary to polish all irregularities. If desired, you can repeat the procedure with the 1000th skin. Since the trunk after the described manipulations will move from a place, it will be necessary to re-make a groove under the shaft axis. The chamfer also has to be renewed. It is done in the same way as the muzzle.

Conclusion

Today we have figured out how to make tuning MP-512. After the described operations aimed at increasing the accuracy and power of the rifle, you can do more fine tuning.

Adhering to the recommendations discussed above, you can significantly improve the performance of the rifle. If everything is done correctly, its power can reach 20 J, and the accuracy is 10-20 mm from a distance of 25 m. With such indicators it is possible to feel confident both when training shooting at targets and at hunting from a distance of up to 50 meters.

Rifle MP-512, the price of which really pleases, after the upgrade becomes a completely different weapon. It is devoid of "childhood diseases" such as poor balance, poor descent and constant vibrations. The accuracy and power of the MP-512 (bullet speed ranges from 250-280 m / s) allows the rifle to compete with more expensive counterparts.