DPM Systems Technologies Ltd.

Article in "GUNS B.G" 2006/11 (Bulgaria)


An ex member of antiterrorist team and actual permanent Police officer invented a mechanism for the recoil's reduction of guns, which quickly became acquaintance in the international market. In relation to a lot of other mechanisms of this type, his mechanism really works!


The recoil is one of the most unpleasant effects upon firing, more specifically when it is a matter of fast shot in sporting shooting. This is direct result of shot, while its force depends on the mass of the bullet, on the charge of gunpowder that exists behind the bullet and on the mass of the gun. As heavier and faster is the bullet, so much stronger is the recoil, as heavier is the gun so much softer is the recoil. The recoil is the vibration that the shooter feels upon shooting, the barrel's bounce is the secondary effect and it depends on the construction of the gun.

Upon shooting when the bullet leaves the barrel, the gases of high pressure that are pushing it, push also the slide back and cause a shift that is parallel and coincides with the barrel's axis. On the other hand, for the hand that supports the arm, the shift is also parallel with opposite direction of impulse force, which is created by the produced gases. The distance between the two opposite shifts determines the force of (propensity of rotation) torque. That is to say as long as more remote are the shifts by the conceivable axes so much more possible is the (propensity of rotation) torque and the corresponding barrel's bounce. On the contrary as closer in the conceivable axes this shifts are found, so much smaller will be the (propensity of rotation) torque.

For this reason the pistols in which the barrel is placed high, as the Sig Sauer P226, jerk more at the shot in relation to the Glock 17 the barrel of which is placed down. In the pistols of rapid fire, the barrel is placed so much down that the mechanism of the slide and the magazine are placed almost in the front side of the grip.
In the automatic guns, like pistols, the slide's movement backwards creates other datum that increases the bounce - that is to say of the slide's strike against the frame when it reaches the final position. This strike is parallel to the axis and consequently it increases additionally the torque at the final phase of recoil.

Existing systems of recoil's reduction are of three basic types.
The first system is the addition of extra weight under the gun's barrel. This is applicable only in the guns of sporting shooting, and it is not applied in the official guns, which are intended for self-protection or for dynamic sporting shooting.

The second system and rather more effective than the first, is the system of compensator of gases' escape (Flash Suppressor). This system puts on redirection the gases of the barrel, in direction that is opposite to the direction of torque that is created at the recoil, in this way the barrel is pushed down.
The compensator requires two arrangements: the first is the gun's dimensions; the compensator increases its length. The second arrangement is the decreased initial speed of bullet. When we have compensator for the decrease of gun's reaction and because of the fact that it is constituted of serial perpendicular sections in the edge of the barrel, that is to say the barrel have holes, and there is loss of gases which promote the bullet.
There is also other mechanism that resembles too much the compensator, however it functions in different way and it is named muzzle brake. Its difference to the compensator, who directs the gases only up, is that the muzzle brake directs the larger percentage of gases left and right or round the barrel at 360 degrees, so as to decrease the impellent force of torque that is created upon shooting. Also muzzle brakes, similar to the compensator, are some certain systems that increase the gun's dimensions, but they cannot however be applied in small semi-automatic guns.

The third system of recoil's reduction, are the mechanisms of damping or mechanisms of reversible springs of type absorber, that is to say a lot of springs that replace the basic spring of slide's rollback. Their effect is less than the effect of compensator but the mechanism of damping of many springs is most popular, because it does not change neither the dimensions of the gun nor the initial speed of bullet. Guns with such system can not be compared with the guns in which is not placed this system. The difference is noticeable upon firing and it is even more detectable the result of mechanism of multiple springs when the munitions of gun are heavier.
The systems of recoil's reduction that exist in the present, have a basic, softer spring, behind which is placed a second harder and shorter spring, which has the role to make softer the last ramming of the slide on the frame.

The system of multiple springs, which was developed by Greek ex-commando and in the present Police Officer Dimitrios Mantas, is constituted of three springs connected in a mechanism of absorber's type, and in the opinion of many special gun-magazines and of many laboratories it is the most effective system for recoil's reduction, that was invented till now. The company of production is named "DPM Systems Technologies Ltd."

The system is constituted of central punched axis with gradual widening in the back 1/3 of its length and externally, in the central axis is placed a second thinner axis. Round the big axis there is the first big spring and round the thinnest axis there is the second, hardest spring, which is placed in the back widening of big axis. In the front side of the central axis is placed the third harder spring. The point of mechanism is to decrease the speed of slide as far as possible by a soft and transitional way, so when the slide approaches at its final place to bring on minimal energy and not to be a direct bump on the frame.


The moment that the bullet upon firing leaves from the barrel, the impulse, that is abruptly created, pushes the slide back, to the moment that the barrel is unlocked of the slide's slots, while the slide is still moving back because of momentum. At this phase firstly the bigger and softer spring starts compressing, till the slide reaches the widening of axis, then this spring stops compressing.
From this moment and on begins compressing the second, harder spring, the axis of which some time abuts against the third harder spring and begins compressing it until the slide's momentum to become equal with the total force of resistance that the three springs offer. At this phase the slide stops its back movement and compelled by the three springs returns forward while drives the next bullet from the magazine and places it in the chamber and it secures again the barrel.
Thus the three springs in specific order of application increase gradually the force with which they react in the slide, decreasing effect of recoil at the shooter, as well as barrel's bounce, because of the smaller slide's vibration (impulse) on the frame. I do not use accidentally the word vibration (impulse), because in this case the bump of the slide on the frame simply does not exist. The sense upon shooting is soft and the recoil is better controlled, without becomes detectable the blow (of hammer) at the hand and appears clearly the less recoil of gun.

Dimitrios additionally created also the Magnetomechanical mechanism for the recoil's reduction, which is achieved with the addition of magnet in the mechanism that already exists. The magnet is incorporated in multilateral base that is placed on the accessory rails, so the magnet applies in front of the slide's forehead under the barrel. The idea for this mechanism was given birth during the service of Dimitrios while he was working with the pistol Glock. The role of magnet is to make softer the initial vibration on the slide and after the shot to attract it back mightily so as to ensure its reliable operation. The second advantage of this base is operational. In all the pistols of moving slide, if the enemy presses with the hand, he will move the slide and the barrel back and therefore the mechanism of trigger and the mechanism of firing pin are disassembled and the shot is impossible. The base placed in front of the slide's forehead does not allow this disassembly.


In the first place it is the effective reduction of recoil, the shooter does not feel the bounce of gun after the shot, this increases the life of gun, because it minimises the dynamic burden on its mechanisms.
Secondly, because of the system of multiple springs, after the shooting the slide comes back with bigger speed, and this decreases the possibility of jams while it enables the experienced shooter to shot right along and faster.
In the Magnetomechanical mechanism, the initial force of slide's unlocking of Glock 17 comes up to 7,3 Kg.
But in the case that is used the factorial spring or the DPM mechanical system for recoil's reduction it comes up only to 4 Kg.
In the same pistol, in the factorial spring the resistance that brings the recoil spring is 4 Kg, which in the final place of slide's slide is increased progressively in 6,8 Kg. At the tests of DPM system of recoil's reduction the slide unlocks with force 4 Kg, which however in the final place of the course is increased progressively in 11,7 Kg. In the Magnetomechanical mechanism of DPM the initial vibration of slide's unlocking is in 7,3 Kg, after the unlocking the resistance is decreased in 4 Kg and is increased smoothly to about 12 Kg.

It was our turn to try the mechanism of DPM. We collected certain individuals: us from the GUNS-BG, as well as the specialist of shooting MILEN DIMITROF. He had the honour to test the Magnetomechanical mechanism on his own Glock 17. His first impression was that the recoil really becomes softer, the gun is better controlled and the line of cock-shy is reconverted faster. He expressed also the same impression after having shot 100 bullets. At the test he was alternating two pistols - the one with conventional spring and the other with DPM.
In the accuracy of the two guns there was not big difference. The difference was showed by the chronoscope PAC-TIMER, at the shot with conventional spring the chronoscope showed that the time between the two shots was 0,18 sec., while at the shot with DPM it was decreased to 0,13 sec. At the analysis of tests via video picture, in the frame by frame pictures it shows clearly that the pistol with the Magnetomechanical mechanism bounds least.

During the last tentative shots with the DPM in Glock 17.

It was then that MILEN find out, that with the DPM mechanism he does not lose even for a moment the line of cock-shy. We tested also pistols of type SIG SAUER 9X19 and SIG SAUER 229, S&W 40 without using the magnet. My impressions was, that it really feels different regarding the recoil, however in no case it is not thus as if does not exist recoil. In the nature nothing is lost, consequently and the energy of recoil. The matter is that here this energy lessens very much. Actually the video showed the big difference between the conventional and the DPM spring as far as I felt, in any case the human estimate is always subjective, with difficulty you can feel something that happens in a split-second.

Finally at the fast shots with the DPM mechanism, the groups of shots were very well gathered and this, for me personally, is indicative for the effectiveness of mechanism. I felt the biggest reduction of recoil shooting with 40 S&W. After the tests that we went through, I offered the springs to some friends of mine for testing them. The impressions were: "I feel something, however the difference is not that much big" to "Fabulous!!! I want to buy it immediately ". The shooter who had the better impressions tested it in pistol 357 SIG!!!.

The DPM mechanism of recoil's reduction is offered for the entire range of Glock, Sig Sauer, CZ, Beretta, S&W and Zastava. Soon mechanisms for other types and models are expected to come in the market. Soon these products will also come in the Bulgarian market; the probable price will be about 100 leva for the mechanism without magnet and 146 leva for the mechanism with magnet, for comparison the corresponding prices in Europe amounts in 55 and 85 Euros. For further information and questions you can send e-mail in the or in telephone 089-67-67-244.

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