Automatic shotgun MP-155 is driven by the gas engine side. The node for adjusting the pressure of the powder gases in the engine, ensuring reliable operation of the gun with a wide range of ammunition, placed in the piston. The transfer node adjustment of the rack of the trunk (as was the predecessor) to the piston in the gun of MP-155 helped to reduce the weight of the barrel, the mass of the piston remains the same. It is necessary to explain that MP-153 piston were made massive in order to provide a good amount of kinetic energy in the moving parts. It is necessary for trouble-free operation in difficult conditions (dirt, frost, ice).
On the piston there is a adjusting nut, biasing spring of the valve. Valve spring pressure on the valve which at a predetermined pressure of gases is shifted, compressing the valve spring and release of the gases from the engine into the atmosphere. Technologically difficult and expensive to manufacture the valve spring is the same, so the settings may differ slightly. Depending on the spring rates are marked with different colors. During Assembly of the piston in accordance with color coded rotating the adjusting nut to achieve the same effort preload of the spring. After running the guns, passing over 100-200 shots, it is recommended to Unscrew the nut 1-2 turns (to loosen the spring preload and thereby reduce the speed of the rollback of moving parts MP-155).
In addition, the adjusting nut can be used for Troubleshooting or tuning. For example, athletes use to fire bullets exclusively with small batches of shot and unable to stop install the nut and tighten the spring that raises the maximum shutter speed MP-155. When using powerful ammunition due to the significantly increased speeds, delays can occur, for example, the absence of the cartridge from the store. In this case, on the contrary, you may need to loosen the preload of the valve spring, which will reduce the gas pressure in the chamber and the speed of pullback. Piston MP-155 at home to parse is not recommended because the valve spring has a very high force preload, and the front nut is tightened with a sealer-locking. For twisting it is necessary to heat the nut to a temperature of depolymerization of the sealant.
Receiver MP-155 is produced from high strength aviation grade aluminum V95. Analogues of this material used by most manufacturers in the world. On top of the box has slots for mounting optics or transition strips. It was originally two pairs of grooves, one to one, however, that in some embodiments, MP-153. But later in the rifle Mr-155 to enhance the versatility and simplification of selection of bracket or optics on the top of the box introduced flatted, it is possible to reduce the required height of the legs of the bracket, and separate the grooves were United in one.
The shutter is generally similar to that of MP-153. Appeared longitudinal valleys, which have a decorative function, they housed a room of guns and stigma, they also contribute to weight loss. Different extractor, to simplify, he became betselem. Sometimes the question sounds: what is the extractor, because most models do without him? The gun can operate without the extractor, but with a quality cartridge with a rigid rim perfect shape. The cartridges are not the best quality, the rim is sometimes sloping. It also may be much to swell and change its shape in the process of the shot. Then the extractor just slides off it. Extractor allows to increase the reliability of the gun.
In MP-155 introduces new features. First - the mechanism of the cutoff of the feed of cartridges from the store, which is located on the left side of the receiver and designed for easy replacement of the cartridge from the chamber. For example, you in the chamber and store the cartridges with a specific number of decimals. Needed to make a shot cartridge other equipment. The procedure will be as follows: include shutoff by turning the check box off back, press the button retinaculum, distort the shutter, the cartridge will be thrown out of the box, and the shutter gets on the sealing delay. Invested the required cartridge in the window to eject spent cartridges, click perehvatyvaet - gate doshlyut cartridge in the chamber and lock the barrel. You can shoot.
At first glance, the procedure is not much easier than the rifles without the mechanism of the cutoff. Benefit becomes apparent when it is necessary to make several shots in a row the other patrons: after each shot the shutter will embark on a shutter delay. You need to invest another cartridge, press the button on perehvatyvaet and you can shoot. If the need for the cutoff rounds in the store anymore, you just have to push your thumb off the box forward. The cartridge will automatically come out of the shop, the bolt will chamber the next round it into the chamber and lock the barrel. The gun is ready to fire. Only when shutting down in any case impossible to hold the box cutoff is may lead to medovuhu cartridge from the store. It is only necessary to slightly shift the check box, and in off state it will return. To understand the mechanism of the cutoff is not recommended because the screw securing the spring blade, twist locking, sealant and there is a risk to disrupt the slot of the screw.
From MP-155 appeared the possibility of adjusting the allotment of the stock both in vertical and in the horizontal plane. By itself the stock does not have a horizontal branch, it is symmetric. In the delivery condition on a shotgun MP-155 between the buttstock and receiver installed liner, ensure the removal of the butt to the right. You can flip the liner, and then the removal will be left is convenient for left-handed shooters. Complete with a shotgun MP-155 includes two liner, one increases vertical drainage by approximately 7 mm, the second as reduces. Initially, the liners were made of metal, then moved on to plastic. Liners can be installed together or separately. On a shotgun MP-155 is mounted the butt plate of the new design is able to effectively dampen recoil in lightweight rifles. There are 2 sizes of stelnikov, differing in length by 1 cm Thus, by replacing the recoil pad to adjust the length of the butt.
Handguard rifle MP-155 also has undergone a transformation. In form it was conical, tapering to the muzzle part. Now in the coverage area of the arm the forearm has a thin section that serves for an easy hold. And to provide strength to the back of the forearm thickens.
Rifle MP-155 can be manufactured for left-handed shooters. Difference: the working order of fuse reverse, the withdrawal of the stock left, the window to eject shells and the handle is located also on the left.
During the design process, every detail, every element of the rifle MP-155 was designed for manufacturability and to minimize weight without sacrificing strength. The gun is so light, comfortable, with original and recognizable design. The weight of the gun with the barrel in the tree, and the caliber 12х76 average of 3.05 kg caliber 12х89 - 3,15 kg. In plastic mass above 100 g.
During production MP-153 there was a question about the possibility of creating on its basis a self-loading rifle 20 gauge. But this idea was quickly abandoned, as to make a gun of reasonable weight and size would have had to redo it. In the terms of reference for MP-155 was immediately agreed modification in 20 gauge. Today it is already in an advanced stage of work on the debug version of MP-155 calibre 20х76. The weight of this modification will be not more than 2.9 kg.
On the basis of the self-loading rifle Mr-155 was created by a pump gun MP-135. The main difference between Mr-135 from the shotgun MP-133 - unification with the MP-155. As a result, the weight of the new pump was significantly lower, approximately 2.9 kg per tree. The performance of the gun MP-135 can be the same as the MP-155 with the following differences. Added options with a barrel length of 510 and 540 mm. Rifle MP-133 had shutter delay, i.e. after the exhaustion of the ammunition the bolt with the forend blocked in the rear position, to unlock you have to click on perehvatyvaet. Part of consumers have expressed the wish to have a gun without a slide stop, and MP-135 there is a possibility of fabrication in this embodiment.
Currently, the development of the pistol grip and collapsible buttstock new. Folding stock used on the MP-153 that was reliable and functional, using elements from the AK-74M. But for a shotgun, much more than on the machine, the impact, it was not very convenient. It is planned that the new butt will be convenient and suitable for use in the variant for left-handers.
Work is underway on creation and modification of the gun for practical shooting. It turned out that the enlarged button retinaculum, more comfortable for shooters, hunters, absolutely not satisfied with the gunners-athletes: quick loading on the button you can accidentally press that will cause the hesitation and loss of time in exercise. These and other requirements will be taken into account in the new version.
When you create a new gun failed to avoid some childhood diseases, but work on deficiencies and improve the model continuously and efficiently. Model self-loading rifles of other manufacturers to compete, especially the Turkish in the lower price range. But the undeniable advantage of our weapons remain: reliability, dependability, and durability, provided precise design and quality materials.
Surely the reader, the potential owner of MP-155, the question arises about the comparative characteristics of "Murka". If you try to compare MP-155 with the main rivals of Western production, then we get the following. Italian gun manufacturers, which is today called legislators rifle mods, have great ergonomics, excellent performance, high level of finish. This is the result of advanced engineering school the advanced technology, powerful economy of the arms companies (which had devastating period, like our "the troubled 90s"). When compared to Italian guns MP-155 is inferior especially in the level of finish as surface treatment.
But in terms of technical excellence, performance, and reliability of the proposed options, the weapon of the Izhevsk mechanical plant looks pretty decent. But the price of any gun, made in Italy, starting from around 50 and can exceed 100 thousand rubles. MP-155 times cheaper, i.e. it is in a completely different price category, and consider these "Italians" as competitors not quite right.
Difficult situation (for MP-155), when compared with the shotguns produced in Turkey. The price at them is comparable with the price of the MP-155. The level of finish is very high, constantly growing quality. Again - the objective advantages of MP-155 quality materials, reliability and durability. Here our product is in the conditions of tough competition.
Of course, the time and the market will show who is better and what's more meet the demands of customers. But the new domestic "cats" has all chances to become as popular a gun as the earlier model MP-153.