EP4630749A1

EP4630749A1 - A buffer assembly for a firearm

Info

Publication number: EP4630749A1
Application number: EP22859523.7A
Authority: EP
Inventors: Savo STJEPANOVI
Original assignee: Armanov d o o
Current assignee: Armanov d o o
Priority date: 2022-12-09
Filing date: 2022-12-23
Publication date: 2025-10-15
Also published as: IL320742A; SI26443A; WO2024123254A1

Abstract

The invention relates to a new buffer assembly for a firearm, comprising a housing (1), a recoil spring (2) and a buffer (3) comprised of an outer frame (4), an inner member (5) and at least one gear (6) attached to the housing (1), wherein the outer frame (4) is on a part of its wall on the inner side in the longitudinal direction provided with at least one primary gear rack (4a), and the inner member (5) is in the corresponding part of the wall in the longitudinal direction provided with at least one secondary gear rack (5a), said two gear racks (4a, 5a) being positioned in a way to move in opposite directions because of their engagement with the gear (6). Said construction provides improved shock absorption when firing, as the impact force caused by the movement of the bolt carrier (8) with the bolt (8a) towards the rear section of the firearm is divided between two buffer elements moving in opposite directions. This allows for better shooting accuracy, especially in rapid successive shots and in automatic firing mode.

Description

A buffer assembly for a firearm

The subject of the invention is a new buffer assembly for a firearm, preferably in semi-automatic and automatic rifles operating by gas operation or blowback operation principle, and which provides improved shock absorption when firing, as the impact force caused by the movement of the bolt carrier with the bolt towards the rear section of the weapon and compensated by the buffer assembly is divided between two buffer elements moving in opposite directions. In this way, the impact force of the bolt carrier with the bolt in the direction towards the rear section of the weapon is compensated by the movement of one of the buffer elements in the direction opposite to the movement of the bolt carrier with the bolt. It is desirable that the mass of the buffer element moving in the direction opposite to the direction of the bolt carrier with the bolt should be as nearly equal as possible to the mass of the bolt carrier with the bolt, and since they are moving in opposite directions, their momenta are practically cancelled out, thus allowing better shock absorption, further improving the firing characteristics of the weapon or rifle, making the rifle steadier, there are no undesired barrel deflections from the direction of fire. This allows for better shooting accuracy, especially in rapid successive shots and in automatic firing mode.

Semi-automatic and automatic rifles use a buffer assembly to absorb the weapon's recoil, which is caused by the bolt carrier with the bolt moving backwards when the weapon is triggered. The buffer assembly usually consists of a buffer and a recoil spring located inside the buffer housing ('buffer tube'), the spring being prestressed, and the buffer being located inside the spring and provided in the section where the spring abuts the buffer with an extension which retains the spring in the prestressed condition. The buffer is in contact with the bolt carrier, namely the front section of the buffer abuts with its extension the rear section of the bolt carrier. Upon each triggering, when the hammer of the trigger mechanism strikes the firing pin located inside the bolt and bolt carrier, the firing pin moves forward and strikes the centre of the cartridge. The impact of the pin ignites the primer contained in the cartridge case, which ignites the propellant, producing propellant gases which push the bullet out of the cartridge case. The propellant is usually gunpowder.

In the gas-operation principle, propellant gases are partially vented through a hole at the top of the barrel and travel via a gas block through a gas tube located above the barrel to the bolt carrier at the rear section of the weapon, pushing the bolt carrier backwards. This unlocks the bolt, which, together with the bolt carrier, moves backwards, allowing the empty cartridge case to be ejected. In the blowback principle of the system, the movement of the cartridge case due to the generation of propellant gases upon the propellant ignition directly pushes the bolt and bolt carrier in the opposite direction of fire. The bolt is not mechanically locked at the moment of propellant gas formation, as in the gas-operation principle, but the inertia of the mass of the bolt carrier with the bolt and the recoil spring, depending on the mass of the cartridge, delays the opening of the bolt until the bullet has left the barrel. The operation is very similar to the delayed blowback system where an attempt is made to lock the bolt for a short time in known ways, so that in this case the mass of the bolt, bolt carrier and buffer is reduced.

As the bolt carrier is in contact with the buffer, when the bolt carrier is moved backwards with the bolt, the buffer dampens the weapon's recoil by moving backwards and compressing the prestressed spring. When the spring is released, the spring pushes the buffer forward and at the same time the bolt carrier with the bolt moves forward to its initial position, the bolt inserts a new cartridge into the barrel and the rifle is ready to fire another shot.

The primary function of the buffer assembly is to reduce recoil and to allow cyclic movement of the bolt carrier with the bolt when the rifle is fired. Selecting and adjusting the buffer assembly may have influence on reduced recoil and the velocity of cyclic movement of the bolt carrier with the bolt. For example, in sport shooting, it is desirable that the cyclic movement of the bolt carrier with the bolt is fast enough to maintain the function of the weapon, i.e. the correct extraction and ejection of the cartridge case and the insertion of a new cartridge into the barrel, and that recoil is reduced.

In conventional buffer assemblies, increasing the buffer mass causes the cyclic movement of the bolt carrier with the bolt and the buffer itself to slow down, resulting in a reduction in the rate of automatic action of the rifle. On the other hand, an increase in the mass of the buffer means an increase in unwanted recoil because the combined increased mass of the bolt carrier with the bolt and buffer moves backwards and forwards during operation.

The buffer itself is usually provided in the form of a hollow metal cylinder into which one or more weights are inserted and closed by a bumper, usually made of softer material, which acts as a shock absorber when the buffer moves to its final position when the spring is compressed. The mass of the buffer is easily adjusted by either inserting more weights into the cylinder or by replacing the weights with heavier weights.

Usually, the buffer assembly is arranged at the rear section of the weapon, in the receiver extension, behind the barrel and behind the bolt carrier. The receiver extension is usually integrated into the gunstock, which may be fixed or folding. The receiver extension is preferably detachably attachable to the trigger mechanism housing by known means, for example by a screw connection. The advantage of the buffer assembly being arranged in the gunstock is that the moving mass is directly present in line with the shoulder, thereby reducing upward recoil of the barrel.

Various improvements to buffer assemblies of semi-automatic and automatic rifles are known from prior art. Patent Document No. US8800424 discloses a buffer assembly which reduces friction of the components making up the buffer assembly. The buffer assembly includes a housing containing a rod with a sliding element and a spring, the spring being disposed around the rod and within the sliding element, and the outer surface of the sliding element being surrounded by weights separated by O- rings. The displacement of the sliding element with the weights along the buffer housing in either direction is smoother, and noise is further reduced as the spring does not rub on the inside of the buffer housing.

Prior art also provides for balanced action firearms, which use a counterweight as a buffer that has the same or similar mass as the bolt carrier but moves in the opposite direction to compensate for the recoils caused by the reciprocating motion of the mass and the impact of the bolt carrier on the buffer housing ("receiver extension"). Typically, in such systems, the counterweight is connected to the bolt carrier via gears to allow synchronisation of the movement of the two parts moving in opposite directions. The advantage gained by the balanced operating mechanism is better control of the weapon, especially in fully automatic mode of fire. The balanced action damping system is disclosed in patent document RU 2683036. The balanced action damping system is mounted on the barrel and is located in front of the trigger mechanism. Said damping system does not allow the system to be fitted to an existing weapon without any modification to the existing weapon, as is made possible by the buffer assembly according to the invention which is fitted in the gunstock. Namely, the buffer assembly according to the invention allows an easy replacement of the existing buffer assembly without any modification to the weapon. The existing buffer assembly is simply removed from the weapon and replaced by the buffer assembly according to the invention. As the mass of the buffer assembly is at the rear section, in the gunstock, the rifle is more balanced for the shooter. A further advantage is that the damping system needs not be dismounted for basic cleaning of the rifle.

The above-identified drawbacks are solved by the buffer assembly of the invention, which will be described in more detail hereinbelow and illustrated on the figures which show:

Figure 1 shows the arrangement of a preferred embodiment of the buffer assembly in a weapon Figure 2 shows the preferred embodiment of the buffer assembly in axonometric projection

Figure 3 shows the preferred embodiment of the buffer housing according to the invention

Figure 4 shows the preferred embodiment of the buffer outer frame according to the invention

Figure 5 shows the preferred embodiment of the buffer inner member according to the invention

Figure 6 shows the preferred embodiment of the buffer assembly in exploded view

Figure 7 shows the operation of the buffer assembly, wherein the views A to D follow each other from the initial position to the end position.

In the context of this application, the term 'front' refers to the part of each component which, when the buffer assembly is assembled, faces the bolt carrier, and the term 'rear' refers to the part of each component which, when the buffer assembly is assembled, faces the gunstock.

A buffer assembly, which is inserted into a dedicated receiver extension 9a in the rear section of the weapon and behind a bolt carrier 8 so that the longitudinal axis of the buffer assembly and the longitudinal axis of the receiver extension 9a are aligned with the longitudinal axis x of the barrel of the weapon, comprises a housing 1, a recoil spring 2 and a buffer 3. The buffer 3 consists of an outer frame 4 which is adapted to co-operate with its front side with the bolt carrier 8, that is to say with a rear contact surface 8b of the bolt carrier 8, and with its rear side with the spring 2, and is adapted, through its engagement with the housing 1, to move in the longitudinal axis x and to compress the spring 2, the inner member 5, which is adapted to move in the longitudinal axis x by means of engagement with the outer frame 4, and at least one rotary gear 6 which is fixed to the housing 1 by means of a detachable connection so that an axle 6a of the gear 6 lies in a plane perpendicular to the longitudinal axis x, and wherein the longitudinal axes of the housing 1, the outer frame 4 and the inner member 5 being aligned with the axis x. The outer frame 4 is on a part of its wall on the inner side in the longitudinal direction provided with at least one primary gear rack 4a, and an inner member 5 is in the corresponding part of its wall in the longitudinal direction provided with at least one secondary gear rack 5a, so that the primary gear rack 4a is enabled to engage the secondary gear rack 5a via at least one gear 6. Said two gear racks 4a, 5a being positioned to move in opposite directions due to engagement with the gear 6, thereby enabling, in the operation of the buffer assembly, when the propellant gases push the bolt carrier 8 with the bolt 8a along the axis x towards the gunstock of a weapon 9, the outer frame 4 to move along the axis x in the same direction and compress the spring 2, and at the same time the inner member 5 moves along the axis x in the opposite direction, and when the spring 2 is released, the outer frame 4 moves along the axis x towards the barrel of the weapon, and at the same time the inner member 5 moves along the axis x in the opposite direction.

The housing 1 is configured as a hollow cylindrical body, open at the front and with an extension la at the rear side. The housing 1 has longitudinally arranged guiding means lc adapted to engage with the outer frame 4, to allow the outer frame 4 to slide and thereby to move the outer frame 4 from the initial position to the final position and vice versa. The guiding means are preferably formed as at least one groove lc adapted to engage with the outer frame 4, to allow the outer frame 4 to slide along said groove lc and thereby to move the outer frame 4 from the initial position to the final position and vice versa. The initial position of the outer frame 4, and hence of the buffer assembly, is the position just before the propellant gases cause the bolt carrier 8 with the bolt 8a to move backwards along the axis x towards the gunstock 9 of the weapon, and the final position of the outer frame 4, and hence of the buffer assembly, is the position when the spring 2 is compressed.

The housing 1 is provided with holes Id in the front side for a detachable attachment of the gear 6 to the housing 1 via the axles 6a of the gear 6, the gear 6 being attached to the housing 1 in such a way that the axle 6a of the gear 6 lies in a plane perpendicular to the longitudinal axis x. A recoil spring 2 is inserted in the housing 1 which, when the buffer assembly is assembled, abuts at one end a rear connecting member 4d of the outer frame 4 and at the opposite end abuts the bottom of the extension la.

The extension la may be fixedly attached to the housing 1 or the extension la is detachably attachable to the housing 1, preferably by a screw connection. The extension la allows the length of the housing 1 to be adjusted if necessary, for example due to the longer inner member 5 or when the structure of the rifle necessitates a longer housing 1, in case when the existing buffer assembly is replaced by a buffer assembly according to the invention. In a preferred embodiment, the extension la is detachably fixable to the housing 1 by a screw connection and is formed as a hollow cylindrical body. The detachably fixable extension la further facilitates the positioning or replacement of additional weights 5e.

Optionally, the buffer assembly includes a damping member 7 disposed between the extension la and the rear wall of the receiver extension 9a to further damp the impact of the buffer assembly on the rear wall of the receiver extension 9a. The damping member 7 is made of a soft material and is preferably formed as an O-ring. Since it is desirable to keep the mass of the outer frame 4 as low as possible with respect to the mass of the inner member 5, the outer frame 4 consists of at least two legs 4b connected together at each end by connecting members 4c, 4d, the legs 4b being formed in such a way that they are opposite each other, symmetrically with respect to the longitudinal axis x. The front connecting member 4c is adapted to co-operate with a rear contact surface 8b of the bolt carrier 8 and the rear connecting member 4d is adapted to co-operate with the spring 2. Both legs 4b and both connecting members 4c, 4d delimit a hollow cylindrical space adapted to receive and move the inner member 5 along the axis x.

The outer circumference of the front connecting member 4c is substantially the same as the outer circumference of the housing 1, so that the front connecting member 4c abuts the front of the housing 1 when the buffer assembly is in its end position. The outer circumference of the rear connecting member 4d is substantially the same as the outer circumference of the spring 2, so that the rear connecting member 4d abuts the spring 2 when the buffer assembly is in operation and compression of the spring 2 is enabled.

At least one leg 4b is provided, in a part of its wall on the inner side in a longitudinal direction along its entire length, with the primary gear rack 4a extending from the outer surface of the front connecting member 4c to the outer surface of the rear connecting member 4d and adapted to engage with the associated secondary gear rack 5a formed on the inner member 5 via the gear 6.

The inner member 5, which moves in the opposite direction to that of the bolt carrier 8 with the bolt 8a when the buffer assembly is in operation and therefore counterbalances the mass of the bolt carrier 8 with the bolt 8a, is formed as an elongated body consisting of a front portion 5b and a rear portion 5c, and having at least one secondary gear rack 5a provided in the front portion 5b, in a part of the wall in the longitudinal direction, which is adapted to engage with the associated primary gear rack 4a formed on the outer frame 4 via the gear 6.

Optionally, the inner member 5 has a hollow cylindrical space 5d formed in the rear portion 5c adapted to receive additional weights 5e. Falling out of the additional weights 5e from the hollow space 5d and at the same time allowing easy replacement of the additional weights 5e is accomplished in known ways by means of fastening means 5f, for example by a pin inserted into through holes 5g provided for this purpose through the walls of the hollow space 5d and through the additional weights 5e, or by means of a retaining ring ("seeger") when the additional weights 5e are made of materials which are difficult to drill. The engagement of the primary gear rack 4a with the secondary gear rack 5a, and thus the movement of the inner member 5 along the axis x in proportion to the outer frame 4 in the opposite direction, is made possible by at least one gear 6. The gear 6 is fixed to the housing 1 via the axle 6a of the gear 6, the axle 6a of the gear 6 lying in a plane perpendicular to the longitudinal axis x, and at the same time the free rotation of the gear 6 is made possible.

The engagement of the primary gear rack 4a with the secondary gear rack 5a is made possible by at least one gear 6, wherein due to the engagement with the gear 6said two gear racks 4a, 5a move in opposite directions . Consequently, the primary gear rack 4a and the secondary gear rack 5a are provided in corresponding parts of the outer frame 4 and of the inner member 5; preferably, said gear racks 4a, 5a are positioned so that they substantially face each other, with the gear 6 acting between them.

Optionally, the outer frame 4 has, in a part of its wall on the inner side in the longitudinal direction, at least one sliding protrusion 4e extending along the entire length of the inner side of the wall, and the inner member 5 has, in a part of the wall in the longitudinal direction, at least one associated sliding groove 5h extending along the entire length of the inner member 5, wherein the sliding protrusion 4e is adapted to slide along the associated sliding groove 5h. The sliding protrusion 4e and the associated sliding groove 5h are meant to hold the inner member 5 in the correct position when the inner member 5 is moved along the longitudinal axis.

In one of the embodiments, the sliding surfaces are made as smooth as possible to reduce friction between the outer frame 4, the inner member 5 and the housing 1 as the outer frame 4 and the inner member 5 move relative to each other in opposite directions. Sliding surfaces are surfaces not provided with gear racks and slide along each other as the outer frame 4 and the inner member 5 move along the axis x.

In a second embodiment, additional friction reducing means, such as bearings, are used to reduce friction.

In one of the preferred embodiments, the inner member 5 is shaped so that its mass is distributed symmetrically with respect to the axis x, the same being true for the outer frame 4.

In a preferred embodiment, the buffer assembly illustrated in the figures includes two gears 6 which allow the inner member 5 to move along the axis x in proportion to the outer frame 4 in the opposite direction. The housing 1 is configured as a hollow cylindrical body, open at the front, and is provided at the rear side with an extension la which is detachably attachable to the housing 1 by means of a screw connection. The housing 1 is in longitudinal direction provided with two grooves lc formed symmetrically with respect to the longitudinal axis x and adapted to engage with the outer frame 4, to allow the outer frame 4 to slide along the grooves lc and thereby to move the outer frame 4 from the initial position to the final position and vice versa.

The outer frame 4 is provided with four equidistantly spaced legs 4b mutually connected at each end by connecting members 4c, 4d, such that the legs 4b and both connecting members 4c, 4d delimit a hollow cylindrical space adapted to receive and move the inner member 5 along the axis x. In this case, the outer frame 4 is provided, in a part of its wall on the inner side along its entire length in the longitudinal direction, with two primary gear racks 4a extending from the outer surface of the front connecting member 4c to the outer surface of the rear connecting member 4d, wherein the two primary gear racks 4a face each other, symmetrically in relation to the longitudinal axis x, namely, two opposing legs 4b being provided in a part of their wall on the inner side along their entire length in longitudinal direction with a respective primary gear rack 4a.

Correspondingly, the inner member 5 is provided on the front portion 5b in a part of the wall in longitudinal direction with two secondary gear racks 5a extending along the entire front portion 5b, the secondary gear racks 5a being provided opposite each other, symmetrically with respect to the longitudinal axis x. Each of the two secondary gear racks 5a is positioned substantially opposite the corresponding primary gear rack 4a, so that said gear racks 4a, 5a substantially face each other, and the gear 6 acts between them.

Each of the other two opposing legs 4b, that is to say, each of the legs 4b which is not provided with a primary gear rack 4a, is provided, in a part of its wall on the inner side in the longitudinal direction, with a sliding protrusion 4e extending along the full length of the leg 4b, the sliding protrusions 4e being provided opposite each other, symmetrically in relation to the longitudinal axis x.

Correspondingly, the inner member 5 is provided, in a part of the wall in the longitudinal direction on respective sides, with corresponding sliding grooves 5e, symmetrical with respect to the longitudinal axis x, which extend along the entire length of the inner member 5 and into which the sliding protrusions 4e fit. Each of the two sliding grooves 5e is positioned substantially opposite the corresponding sliding protrusion 4e.

The two gears 6 are fixed to the housing 1 via the axles 6a of the gears 6 and the associated holes Id provided in the housing 1, so that the axles 6a of the gears 6 lie in a plane perpendicular to the longitudinal axis x and the gears 6 are positioned opposite each other symmetrically with respect to the longitudinal axis x. Each of the gears 6 engages with the associated primary gear rack 4a and the associated secondary gear rack 5a.

Operation of the buffer assembly

The operation of the buffer assembly is shown in Figure?. When the buffer assembly is assembled and in its initial position, the recoil spring 2 and the inner member 5, which is, in a part of its wall symmetrically with respect to the longitudinal axis x in longitudinal direction, provided with two secondary gear racks 5a, are located inside the housing 1, with the spring 2 enclosing the inner member 5. Correspondingly, the diameter of the inner member 5 is smaller than the inner diameter of the spring 2. The outer frame 4 is inserted with its rear end into the grooves lc provided in the housing 1, so that the two opposing legs 4b, which are provided in the longitudinal direction with primary gear racks 4a on their inner walls, symmetrically with respect to the longitudinal axis x, extend with their rear ends into the grooves lc, while the other two opposing legs 4b extend into the housing 1. The rear connecting member 4d abuts the front end of the spring 2 and the front connecting member 4c is in contact with the rear contact surface 8b of the bolt carrier 8, thereby prestressing the spring 2 within the housing 1. One gear 6 is fixed on each side of the housing 1 via the axle 6a of the gear 6, so that the gears 6 are positioned opposite each other symmetrically with respect to the longitudinal axis x, each of the gears 6 engaging one primary gear rack 4a and the corresponding secondary gear rack 5a. When a shot is fired and the bolt carrier 8 with the bolt 8a starts moving rearwards, at the same time the outer frame 4 begins to move rearwards towards the rear section of the weapon and compresses the spring 2. At the same time, the inner member 5 begins to move forwards, in the opposite direction to that of the bolt carrier 8 with the bolt 8a, due to the gear connection. When the buffer assembly is in its final position, the compressed spring 2 starts to decompress, with the spring 2 pushing the outer frame 4 in a forward direction towards the barrel, at the same time the bolt carrier 8 with the bolt 8a starts to move forward, and, due to the gear connection, the inner member 5 starts to move backwards in the opposite direction to the movement of the bolt carrier 8 with the bolt 8a. As the mass of the inner member 5 is as nearly equal as possible to the mass of the bolt carrier 8 with the bolt 8a, and since they are moving in opposite directions, their momenta are practically cancelled out, thus allowing better shock absorption.

The buffer assembly according to the invention thus allows the rifle to maintain the characteristics when shots are fired as if a heavier mass had been used in a conventional buffer assembly, which is desirable especially in "blowback" systems, while at the same time, due to the better shock absorption, the accuracy of the shooting is improved, especially in rapid successive shots and in the automatic firing mode.

Claims

1. A buffer assembly for a firearm, wherein the buffer assembly is inserted into a dedicated receiver extension (9a) in the rear section of the weapon and behind a bolt carrier (8) so that a longitudinal axis of the buffer assembly and a longitudinal axis of the receiver extension (9a) are aligned with a longitudinal axis (x) of a barrel of the firearm, and the buffer assembly comprises a housing (1), a recoil spring (2) and a buffer (3), characterized in that the buffer (3) is comprised of: an outer frame (4) which is adapted to co-operate with its front side with the bolt carrier (8), that is to say with a rear contact surface (8b) of the bolt carrier (8), and with its rear side with the spring (2), and is adapted, through its engagement with the housing (1), to move in the longitudinal axis (x) and to compress the spring (2); an inner member (5) which is, through its engagement with the outer frame (4), adapted to move along the longitudinal axis (x) and at least one rotary gear (6) which is fixed to the housing (1) with a detachable connection, such that an axle (6a) of the gear (6) lies in a plane perpendicular to the longitudinal axis (x); the longitudinal axes of the housing (1), the outer frame (4) and the inner member (5) being aligned with the axis (x), the housing (1) being longitudinally provided with guiding means (lc) adapted to engage the outer frame (4), wherein the outer frame (4) is on a part of its wall on an inner side in the longitudinal direction provided with at least one primary gear rack (4a), and the inner member (5) is in a corresponding part of its wall in the longitudinal direction provided with at least one secondary gear rack (5a), said two gear racks (4a, 5a) being positioned to move in opposite directions due to engagement with the gear (6), thereby enabling, in the operation of the buffer assembly, when the propellant gases push the bolt carrier (8) with the bolt (8a) in longitudinal direction towards a gunstock (9) of the firearm, the outer frame (4) to move along the axis (x) in the same direction and compress the spring (2), and at the same time the inner member (5) moves along the axis (x) in the opposite direction, and when the spring (2) is released, the outer frame (4) moves along the axis x towards the barrel of the firearm, and at the same time the inner member (5) moves along the axis (x) in the opposite direction.

2. The buffer assembly according to claim 1, characterized in that the housing (1) is configured as a hollow cylindrical body, open at a front and with an extension (la) at a rear side, the housing (1) being provided on the front side with holes (Id) for a detachable attachment of the gear (6) to the housing (1) via the axle (6a) of the gear (6), and the housing (1) is provided with guiding means in a form of at least one groove (lc) in longitudinal direction which is adapted to engage with the outer frame (4) to allow the outer frame (4) to slide along said groove (lc) and thereby to move the outer frame (4) from its initial position to its final position and vice versa.

3. The buffer assembly according to claim 2, characterized in that the extension (la) is either fixedly attached to the housing (1) or the extension (la) is detachably attachable to the housing (1).

4. The buffer assembly according to claims 1 to 3, characterized in that the outer frame (4) is comprised of at least two legs (4b) connected together at each end by connecting members (4c, 4d), the legs (4b) being formed in such a way that they are opposite each other, symmetrically with respect to the longitudinal axis (x), wherein the front connecting member (4c) is adapted to co-operate with the rear contact surface (8b) of the bolt carrier (8) and the rear connecting member (4d) is adapted to cooperate with the spring (2), and wherein both legs (4b) and both connecting members (4c, 4d) delimit a hollow cylindrical space adapted to receive and move the inner member (5) along the axis (x), and at least one leg (4b) is provided, in a part of its wall on the inner side in the longitudinal direction along its entire length, with the primary gear rack (4a) extending from an outer surface of the front connecting member (4c) to an outer surface of the rear connecting member (4d), and adapted to engage with the associated secondary gear rack (5a) via the gear (6).

5. The buffer assembly according to claims 1 to 4, characterized in that the inner member (5) is formed as an elongated body consisting of a front portion (5b) and a rear portion (5c), and having at least one secondary gear rack (5a) provided in the front portion (5b), in a part of the wall in the longitudinal direction, which is adapted to engage with the associated primary gear rack (4a) via the gear (6).

6. The buffer assembly according to claim 5, characterized in that the inner member (5) has a hollow cylindrical space (5d) formed in the rear portion (5c) adapted to receive additional weights (5e).

7. The buffer assembly according to claims 1 to 6, characterized in that the outer frame (4) has, in a part of its wall on the inner side in the longitudinal direction, at least one sliding protrusion (4e) extending along the entire length of the inner side of the wall, and the inner member (5) has, in a part of the wall in the longitudinal direction, at least one associated sliding groove (5h) extending along the entire length of the inner member (5), wherein the sliding protrusion (4e) is adapted to slide along the associated sliding groove (5h).

8. The buffer assembly according to claims 1 to 7, characterized in that the buffer assembly includes two gears (6) that are fixed to the housing (1) via the axles (6a) of the gears (6) and the associated holes (Id) provided in the housing (1), so that the gears (6) are positioned opposite each other symmetrically with respect to the longitudinal axis (x), and wherein each of the gears (6) engages with the corresponding primary gear rack (4a) and the corresponding secondary gear rack (5a).

9. The buffer assembly according to claims 1 to 8, characterized in that the housing (1) is provided in longitudinal direction with two grooves (lc) formed symmetrically with respect to the longitudinal axis (x).

10. The buffer assembly according to claims 1 to 9, characterized in that the outer frame (4) is provided with four equidistantly spaced legs (4b), wherein two opposite legs (4b) are provided in a part of their wall on the inner side along the entire length in longitudinal direction with a respective primary gear rack (4a), wherein the two primary gear racks (4a) face each other, symmetrically in relation to the longitudinal axis (x).

11. The buffer assembly according to claims 1 to 10, characterized in that the inner member (5) is provided on the front portion (5b) in a part of the wall in longitudinal direction with two secondary gear racks (5a) extending along the entire front portion (5b), the secondary gear racks (5a) being provided opposite each other, symmetrically with respect to the longitudinal axis (x), each of the two secondary gear racks (5a) being positioned substantially opposite the corresponding primary gear rack (4a), so that said gear racks (4a, 5a) substantially face each other, and the gear (6) acts between them.

12. The buffer assembly according to claims 1 to 11, characterized in that the inner member (5) and the outer frame (4) are formed in a way to have their masses distributed symmetrically with respect to the axis (x).

13. The buffer assembly according to claim 10, characterized in that each of the other two opposing legs (4b) which is not provided with the primary gear rack (4a), is provided, in a part of its wall on the inner side in the longitudinal direction, with the sliding protrusion (4e) extending along the full length of the leg (4b), the sliding protrusions (4e) being provided opposite each other, symmetrically in relation to the longitudinal axis (x), and the inner member (5) is provided, in a part of the wall in the longitudinal direction on corresponding sides, with corresponding sliding grooves (5e), symmetrical with respect to the longitudinal axis (x), which extend along the entire length of the inner member (5) and into which the sliding protrusions (4e) fit, such that each of the two sliding grooves (5e) is positioned substantially opposite the corresponding sliding protrusion (4e).

14. The buffer assembly according to claims 1 to 13, characterized by additionally including a damping member (7) disposed between the extension (la) and the rear wall of the receiver extension (9a) to further damp the impact of the buffer assembly on the rear wall of the receiver extension (9a).