Patent Publication Number: US-2005132875-A1

Title: Locked automatic and semi-automatic firearms

Description:
RELATED APPLICATION  
      This patent arises from a continuation of International Patent Application Serial Number PCT/EP03/09490, which was filed on Aug. 27, 2003 and is hereby incorporated by reference in its entirety. 
    
    
     FIELD OF THE DISCLOSURE  
      This disclosure relates generally to firearms, and, more particularly, to locked automatic and semi-automatic firearms.  
     BACKGROUND  
      Throughout this patent, position designations such as “above,” “below,” “top” “forward,” “rear,” etc. are referenced to a firearm held in a normal firing position (i.e., pointed away from the shooter in a generally horizontal direction).  
      Semi-automatic firearms with sensitive cartridge cases, in particular semi-automatic shot guns, have always been problematic. In particular, problems arise due to the extremely low shelf life of the cartridges vis-à-vis residual pressure when loading the weapon. With semi-automatic shot guns, it is also the case that cartridges with exactly the same measurements can have very different payloads, which in turn makes for different residual pressures.  
      Additionally, the lock on many semi-automatic weapons tends to open when the bullet is still in the barrel and/or when the gas pressure has not fallen sufficiently.  
      With a semi-automatic weapon, like a shot gun or a semi-automatic pistol designed for strong cartridges and/or a long-barreled pistol, low residual pressure will cause most cartridge shells to inflate or burst when the lock is opened. Such residual pressure is unavoidable in a simple semi-automatic pistol with a blow-back lock. But locked recoil loaders also have residual pressure when opening that is no match for some small-shot cartridge shells when the lock is opened. Recoil-loading semi-automatic rifles, which are made for weak cartridges, also have problems with stronger munitions as a rule. These problems can be attributed to the increased residual pressure associated with stronger munitions.  
      Shot-gun cartridge shells have, in the past, been made entirely of metal. However, due to the high price and weight associated with such a construction, such metal shells were not generally accepted.  
      An additional problem is the low tensile-load capacity of a shot-gun cartridge shell in its longitudinal direction. With cheap shot-gun cartridge shells made of cardboard with metal bottoms, such loads may cause the metal bottom in the cartridge chamber to separate from the remainder of the shell. The low conicity of shot-gun cartridges supports this tendency.  
      For approximately 100 years, shot guns have used a recoil-loading system in which, upon the firing of a shot, the barrel and the closed lock first run back over the full return range. The pressure is almost completely dissipated in this run-back process. (Browning, Walther type weapons utilize this sort of recoil loading system.) In such systems, after the lock reaches the rearmost position, the lock remains fixed in its rearmost position, the barrel is decelerated under the power of a spring, and the barrel is then returned relatively slowly towards the front. The lock and the cartridge shell remain stationary as the barrel returns to the forward position, so that the cartridge is gently extracted from the barrel. Thus, excessive forces do not act upon the cartridge shell. After the ejection of the cartridge shell, the lock snaps forward again under the effect of the recoil spring. In the process, the lock carries a new cartridge forward into the cartridge chamber.  
      Such a shot gun is very reliable—even with differently loaded munitions. But, it has two different disadvantages. First, a built-in brake is provided to slow the movement of the barrel and perform an adjustment for extreme loading differences (i.e., for different sized cartridges). However, this brake only works under strictly defined conditions (for example, only when the components are slightly oiled). Second, the relatively slow, powerful backwards movement of the barrel requires support from the housing. This support takes place in that the weapon is pressed into the shoulder of the shooter. However, if the weapon is shot from the hip, then this support is not provided, which can lead to serious loading malfunctions. Such a system is, therefore, not suitable for shot guns that are used in military and/or police applications.  
      Recently, the tendency has been to switch to gas pressure loaders for shot guns. Gas pressure loaders have long been used in semi-automatic rifles and have proven themselves in that context. But, semi-automatic shot guns require a defined gas pressure and an easily removable shot cartridge shell. With modem, powerful cartridges that have a cartridge floor made of metal with a long sleeve and a shell body made of longitudinally ribbed plastic, such gas pressure loader shot guns enjoy trouble-free operation. Moreover, even with poor quality cartridges, gas pressure loader firearms do not have the support disadvantage of recoil-loading shot guns. Thus, the gas pressure loader functions the same when the weapon is fired from the hip and when the weapon is fired from the shoulder.  
      However, gas pressure loaders are very complicated. Depending on the powder used, they require different levels of cleaning and are susceptible to dirt, rust, and lack of oil due to the many metal-on-metal contact areas. Cutting down on gas pistons by loading the lock with drawn-off powder gases leads to structural simplification, but increases the danger of contamination.  
      Modern recoil loaders are also known that operate without movement of the barrel (e.g., the G3 weapon). However, this functionality is achieved at a cost in sensitivity with respect to munitions. In other words, such recoil loading weapons, in particular these types of shot guns, are very sensitive as far as munitions are concerned.  
      Another recoil-loading system that is locked, but still has a rigid barrel, is also known for shot guns. This system, which is described in U.S. Pat. No. 4,604,942, has a lock mount seated loosely in the weapon. The lock mount remains in position due to its mass inertia while all other parts of the weapon run backwards due to the recoil. The lock mount and the lock head are designed such that they eventually strike each other. This seemingly simple weapon is, in fact, very complicated. Moreover, the recoil loading system does not seem to function safely, as a weapon that came to market with this system is no longer offered for sale.  
      This system was later combined with a pump gun mechanism in the Benelli Super M 3. In that combination, the semi-automatic activity could be optionally switched off. These known weapons have a tube magazine, which does not make sense for an issued weapon. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a longitudinal cross-sectional view through the rear part of the barrel piece and the lock of an example shot gun shown in a closed and locked lock state.  
       FIG. 2  is a cross-sectional view of the example weapon of  FIG. 1 , but showing the weapon with an unlocked lock immediately after the firing of a bullet.  
       FIG. 3 . 1  is a longitudinal cross-sectional view through the lock mount of  FIGS. 1 and 2 , but shown in a slightly larger scale than that used in  FIGS. 1 and 2 .  
       FIG. 3 . 2  is a top perspective view of the example lock mount shown in  FIG. 3 . 1 .  
       FIG. 4  is a cross-sectional view through the rear part (end section) of the barrel piece of  FIG. 1 , shown along the center axis of a locking recess.  
       FIG. 4   a  is an enlarged view of the item of  FIG. 4 , shown transversely to the longitudinal direction of the weapon.  
       FIG. 5 . 1  is a rear view of the example locking block.  
       FIG. 5 . 2  is a side view of the locking block of  FIG. 5 . 1 .  
       FIG. 6  is a top perspective view of the lock shown approximately in the state shown in  FIG. 1 .  
       FIG. 7  is a greatly enlarged view of an example extractor claw.  
       FIG. 8  is a side view of the dismantled block.  
       FIG. 9  is a cross-sectional view of the dismantled block, taken along line IX-IX of  FIG. 8 . 
    
    
     DETAILED DESCRIPTION  
      The example weapon shown in  FIGS. 1 and 2  is a semi-automatic shot gun that can be provided with a case magazine. The shot gun of  FIG. 1  has a barrel piece  1  with a center or bore axis  37 . A cartridge chamber  3  is located in the rear part of this barrel piece  1 . An end section  4  of the barrel piece  1  defines the cartridge chamber.  
      The end section  4  has an almost U-shaped cross-section. As shown in  FIG. 4 , the U-shaped cross-section of the end section  4  is open on the bottom, has a concentric, upper locking recess  5 , and two locking notches  6  on the bottom. The locking notches  6  are located in the free ends of the two legs of the U-shaped cross-section. A cannelure  10  is provided at approximately half the height of each leg of the U-shaped cross-section. Each cannelure  10  runs parallel to the bore axis  37 . A cartridge extractor  61  such as that shown in  FIG. 7 , can run in each of these cannelures  10 .  
      When the weapon is ready to fire as shown in  FIG. 1 , the cartridge chamber  3  is locked toward the back by a lock head  11 . The lock head  11  is penetrated by a front, vertical, transverse drill hole that receives a locking block  25 . As shown in  FIG. 5 . 1 , the locking block  25  has an upside-down T-shaped cross-section which is oriented perpendicularly relative to the bore axis  37 . The locking block  25  has a conical locking appendage  7  on the free (upper) end of its center shaft. As also shown in  FIG. 5 . 1 , the locking block  25  includes a locking finger  8  on each of the two ends of the (lower) transverse shaft. In the locked position, the locking appendage  7  engages with the locking recess  5  and the locking fingers  8  simultaneously engage with their corresponding locking notches  6 .  
      In the example shown in the figures, all of the engagement surfaces are sloped with respect to a vertical line in order to facilitate effortless engagement and detachment of the locking block  25  in the end section  4  of the barrel piece  1 . However, in the illustrated example, the sloped angles of the surfaces are so low that the engagement is self-blocking, (i.e., the engagement cannot be released by applying a force on the lock head  11  along the bore axis  37  towards the back of the weapon).  
      As a result of the engagement of the locking block  25  and the rear section  4  of the barrel piece  1 , the barrel piece  1  and the lock head  11  are directly connected with each other during a shot. Therefore, the barrel piece  1  and the lock head  11  transfer high initial forces directly to each other. No other element is affected by this transfer of force. The back end of the barrel piece  1  can, therefore, be embedded into a plastic housing  2  because the largest occurring forces are not discharged into the housing  2 .  
      In the illustrated example, the lock head  11  sits on a lock mount  13 , which is shown in detail in  FIGS. 3 . 1  and  3 . 2 . The lock mount  13  can be moved a certain distance longitudinally relative to the lock head  11 . The lock mount  13  has a longitudinal recess  54 , a transverse recess  53  in the area below the locking block  25 , and level surface  59  behind this recess  53 .  
      The transverse recess  53  is bordered on each side of the longitudinal recess  54  by a nose  55  (see  FIG. 3 . 2 ). Each nose  55  flanges upward and backward as shown in  FIG. 3 . 1 . Each flange terminates at a height above the level surface  59 .  
      The locking block  25  is designed such that, in its upper locking position, the lower surface of its transverse shaft is rounded off almost flush with the lower surface of the lock head  11  ( FIG. 1 ). In this position, the lock mount  13  can move forwards and backwards under the locking block  25  and the lock head  11  and the locking block  25  can thereby glide on the level surfaces  59  of the lock mount  13 .  
      However, if the lock mount  13  moves backwards from the resting position shown in  FIG. 1 , then both noses  55  engage the transverse shaft of the locking block  25  with their rear edges. As a result, the noses  55  pull the locking block  25  down into the transverse recess  53  into the position shown in  FIG. 2 . In this position, the lock block  25  disengages from the end section  4  of the barrel piece  1 . As a result of this disengagement, the lock head  11  is free to move backwards relative to the barrel piece  1 .  
      During further backward movement, the unlocked lock head  11  runs in a guide (not shown) in the housing  2 . During this rearward movement, the locking block  25  is held such that it cannot move upward.  
      When closing, the lock head  11  hits the rear end of the cartridge chamber  3 . The lock mount  13  is then pulled or pushed further forward by a recoil spring  9  (shown schematically in  FIGS. 1 and 2  as the direction of force  9 ). In this process, one taper  57  forming the back wall of the transverse recess  53  cams the locking block  25  in the upward direction until the level surface  59  reaches under the locking block  25  and the position of  FIG. 1  is reached once again.  
      A pivotable dismantle block  27  is located in the lock head  11  behind the locking block  25 . The dismantle block  27  is held in its position of use by a pin  28  (see  FIGS. 1, 2 ,  6 , and  8 ,  9 ). The dismantle block  27  is located in a rear, vertical transverse bore  23  in the lock head  11 . The pin  28  can be disengaged via the bore hole  24  in the lock head  11  as shown in  FIG. 6 .  
      The lock block  25  and the dismantle block  27  are penetrated by a striker or firing pin  19 . Each of the lock block  25  and the dismantle block  27  has a bore  31 ,  34  to permit this penetration.  
      The lower end of the dismantle block  27  is designed like a hammer foot  51 . The hammer foot  51  runs in a groove  49  defined in the lock mount  13  (see  FIG. 3 . 2 ). The groove  29  is open on the top and has an upside-down T-shaped cross-section. In the operational state, (i.e., in the position of use), the hammer foot  51  reaches below the flanks of the groove  49  and the dismantle block  27  is held by its pin  28 . In this operational state, a projection  35  of the striker/firing pin  19  hits a protrusion  36  (see  FIG. 9 ) located behind it in the bore hole  34  of the dismantle block  27 . This engagement of the firing pin  19  and the dismantle block  27  prevents the striker/firing pin  19  from falling backwards out of the lock head  11 . If the dismantle block  27  is rotated by approx. an eighth of a turn (e.g., after removing the pin  28 ), then the striker/firing pin  19  can be removed toward the back. Since, in this state, the hammer foot  51  still reaches under the upper flanks of the groove  49 , the lock head  11  and the lock mount  13  still remain assembled, while the striker/firing pin  19  can be replaced with a new one. Only a full quarter turn of the dismantle block  27  (which, of course, is only possible after removing the striker/firing pin  19 ) releases the hammer foot  51  from the groove  49  and permits the lock head  11  to be lifted from the lock mount  13 .  
      As shown in  FIG. 5 . 1 , the bore  31  in the locking block  25  (which is penetrated by the striker/firing pin  19 ) is structured as an elongated hole to permit the locking block  25  to move between the positions of  FIGS. 1 and 2  (locked and unlocked) despite the presence of the striker/firing pin  19 .  
      The striker/firing pin  19  has an enlarged section  29  behind the elongated hole  31 . As shown in the example of  FIG. 5 . 1 , a recess  33  which is sloped complementary to the enlargement  29  is formed in the bottom of the backside of the elongated hole  31 . The recess  33  and the enlargement  29  are formed such that the striker/firing pin  19  can only penetrate the elongated hole  29  when the locking block  25  is located in its uppermost position (i.e., the locking position shown in  FIG. 1 ). In this position, the striker  19  can be inserted so far into the elongated hold  31  that its tip can stick out of the front surface of the lock head  11  for firing a cartridge.  
      If the locking block  25  is lowered, due to its special form the recess  33  presses the enlargement  29  of the firing pin  19  backward such that the tip of the firing pin  19  cannot reach a cartridge. This ensures that a cartridge can only be fired if the lock head  11  is properly locked.  
      The enlargement  29  and the projection  35  cooperate to hold the firing pin  19  loosely between two positions, namely, a forward position and a rearward position. The sloped recess  33  of the locking block  25  forces a withdrawal of the firing pin  19  during unlocking. A striker spring is, thus, generally superfluous and, therefore, does not need to be provided.  
      A handle such as, for example, a re-locatable front shaft, may be attached to the lock mount  13 . An unlockable latch may place this handle in the foremost position. In this case, a recoil spring  9  is not required, but rather the handle and, thus, the lock mount  13  are moved back and forth to load the weapon.  
      The provided examples are directed toward a semi-automatic loader. In these examples, the lock head  11  is elongated toward the back by a centric extension pipe  15 , which receives and guides the elongated striker/firing pin  19 . The rear end of the lock mount  13  extends upward to form a counter bearing  43 .  
      An intermediate piece  39  of the lock mount  13  is suspended in front of and at a distance from the counter bearing  43 . The intermediate piece  39  is suspended from above. The forward position of the intermediate piece relative to the lock mount  13  is limited by a step  40  (see  FIG. 1 ), but the intermediate piece  39  can be moved towards the back.  
      The counter bearing  43  and the intermediate piece  39  each have a through hole. The through holes are aligned and are penetrated by the extension pipe  15 . The extension pipe  15  serves as a support for a powerful pressure or opening spring  17 . The spring  17  is preferably implemented as a helical, bent wire spring that surrounds the extension pipe  15 . The pressure spring  17  is supported in the relaxed state in the back by the counter bearing  43  and, in the front by, the intermediate piece  39  (such that the intermediate piece  39  sits on the step  40  of the lock mount  13 ). This structured arrangement prevents rattling (due to the back and forth movement of the pressure spring  17 ) when the lock is open.  
      As can be recognized, the powerful opening spring  17  has almost no effect. It only becomes operative when the lock head  11  moves backward relative to the lock mount  13  in the locked position in  FIG. 1 . This type of movement actually occurs during firing. In particular, backward movement is forced on the barrel piece  1  and the lock head  11  locked with it, which seems to remain in position with respect to the heavy lock mount  13 . This backward movement does not need to have a large amplitude. The compression of a shaft cap made of rubber that is supported (e.g., against a wall) is completely sufficient.  
      When one looks at the drawing, this actual movement is hard to imagine. Instead, one can assume that the lock mount  13  moves forward a bit during firing.  
      The following occurs: with this forward motion, the recoil spring(s)  9  are insignificantly unburdened, but in lieu thereof the opening spring  17  is loaded. The intermediate piece  39  and the counter bearing  43  thereby move towards each other. This movement stops depending on the strength of the recoil and the strength of the impulse of the fired cartridge.  
      If this movement comes to a stop through the compromising of the opening spring  17 , then a counter movement is introduced. This countermovement is triggered by the compromised spring  17 . In the course of this counter movement, the lock mount  13  is ripped powerfully backward. As a result, the lock noses  55  of the lock mount  13  pull the locking block  25  downwards and then carry the lock head  11  with it through its further backwards movement. Due to this movement, the rear end of the lock mount  13  stretches the stop-cock of a known cut-off mechanism (not shown), and performs a loading movement. During the subsequent advance, the locking block  25  is pressed upward again in the aforementioned manner and is, then, supported from underneath by the level, upper surface  59  of the lock mount  13 . It does not matter whether or not the lock mount  13  is located one millimeter further forward. Thus, successive tolerances have no influence.  
      As already mentioned, the longer the relative advance of the lock mount  13  during firing, the stronger the recoil. Correspondingly, the stronger the recoil, the more the opening spring  17  is loaded, and, the more powerfully the recoil of the entire lock  11 ,  13 . In order to equalize this, additional shock absorbers are attached in the form of elastomer buffers  41 . To this end, two rods  45  are located parallel to the bore axis  37 . These rods  45  penetrate the counter bearing  43  and are inserted into recesses in the intermediate piece  39 . The rods  45  are arranged on both sides of the center of the lock mount  13 . These rods  45  penetrate the elastomer buffers  41 . A flange  47  is located on each rod  45  between the counter bearing  43  and the buffer  41  to prevent the rod  45  from slipping backward. The recesses are open on the bottom for easy installation.  
      The elastomer buffers  41  are preferably comprised of several ring elements and are preferably made of a material with a high hysteresis. When a weak cartridge is fired, the elastomer buffers  41  are not or are only slightly compromised. But when a very strong cartridge is fired, then both elastomer buffers  41  are greatly compromised. The buffers  41  are structured similarly to a dead bang hammer such that they give back less energy with their renewed expansion than they previously absorbed. The increased recoil energy of strong cartridges is, thus, at least partially destroyed—or, more exactly, converted into other forms of energy. As a result, the lock is able to fire cartridges with very strongly varying recoil energy (and, thus, very widely varying muzzle energy) without having to use a different locking spring  17  and without functional problems. A separate stop between the lock head  11  and the lock mount  13  is missing. Only the opening spring  17  and the elastomer buffer(s)  41  serve as the stop.  
      A further advantage of the illustrated lock  11 ,  13  is that, in its unlocked state (see  FIG. 2 ), the front surface of the lock mount  13  extends a very little distance past the front surface of the lock head  11 . Thus, a cartridge can be forced upward without its bottom getting caught, for example, on a cartridge extractor or on a projection of the front surface of the lock head  11 . The non-impacted lock head  11  also does not try to lock during transport.  
      As can be seen in  FIG. 6 , the lock head  11  of the illustrated example is unusual in that it has two opposite lying cartridge extractors  61 . A larger version of an example cartridge extractor  61  is shown in  FIG. 7 . As can be seen in  FIG. 7 , the example cartridge extractor  61  has a hook-like design with a hook surface  63  turned backwards that is designed to sit on the edge of a shot cartridge from the front. This edge is curved outward and forward so that the hook surface  63  sits on a curved version. Depending on whether the cartridge extractor is arranged on the left or the right, the cartridge shell is ejected on the left or the right. But no eccentric thrust or radial force that could come from an individual cartridge extractor  61  acts on the cartridge shell during ejection. This guarantees the proper ejection of very long cartridge shells. Only near the end of the recoil path of the lock is an eccentric force exerted on the cartridge shell. This eccentric force causes release of the cartridge shell, first from one and then from the other cartridge extractor  61 . Therefore, only the ejector needs to be converted to convert from right to left ejection (or vice versa). Both cartridge ejectors  61  remain where they are.  
      From the foregoing, persons of ordinary skill in the art will appreciate that a new type of semi-automatic handheld firearm has been disclosed that at least partially avoids the above disadvantages of the known recoil and gas pressure loaders.  
      In particular, simple, inexpensive semi-automatic handheld firearms have been disclosed which can be produced with unusually high tolerances and that are particularly insensitive to usage of different munitions.  
      In the disclosed examples, a powerful spring mechanism is arranged between the lock mount  13  and the lock head  11 , via which the (heavy) lock mount  13  is supported when the lock head  11  is locked. Besides the spring mechanism, when the lock head  11  is locked and a shot is fired, there is no impact between the lock head  11  and the lock mount  13 , so that the initial relative movement between these parts  11 ,  13  is not limited by an impact.  
      When the lock head  11  is locked with respect to the barrel  1 , then the weapon is locked. The locking is, as usual, only unlockable if the lock  13  mount moves backwards a bit from this locked position. When the lock mount  13  moves further backward, it takes the lock head  11  back with it. During the subsequent forward movement of the lock mount  13  and head  11 , a cartridge is inserted into the cartridge chamber. The lock head  11  hits the bottom of the cartridge or the cartridge chamber and comes to a stop. The lock mount  13  locks the lock head  11  with respect to the barrel  1  and then comes to a stop.  
      This is the progression of movement with a common recoil loader with a rigid barrel and also the progression of movement when loading the weapon in the examples illustrated in this patent. However, while with all common semi-automatic weapons, the lock mount is pressed by the recoil spring against a fixed impact, (usually against the lock head), in the illustrated example, the lock mount  13  is not affixed to the lock head  11 . Rather, the lock head  11  is supported on the lock mount  13  via a powerful spring mechanism, but can, as a rule, be moved forward without causing an impact. The coordination of the lock spring and the spring mechanism thereby determines the final position of the lock mount  13 . Broad tolerances are possible and allowed here.  
      Incidentally, when speaking of “the lock spring” in this patent, it is understood that a lock spring and/or a lock spring mechanism may comprise one or several springs.  
      During a shot (from the shoulder or from the hip), the weapon illustrated herein performs a short, powerful backwards movement that is felt by the shooter as a recoil. All parts are then stationary with respect to the weapon as a complete entity, (i.e., the stationary barrel  1  and also the locked lock head  11 , also follow this recoil movement).  
      In the illustrated example, the lock mount  13  does not follow the recoil movement, but rather remains in its absolute position as a result of its mass inertia, which is contrary to common practice. This means that, as a result of the recoil, the barrel  1  and the lock head  11  move backward relative to the lock mount  13 , as it were, against the power of the strong spring mechanism  17 ; and, as the case may be, supported by the much weaker lock springs  9 . As seen from the barrel  1 , the barrel  1  and the lock head  11  remain stationary. The lock mount  13  moves forward relative to the barrel  1  and the lock head  11  and is restricted by the spring mechanism.  
      The stronger the cartridge, the stronger the recoil, (i.e., the backward acceleration of the barrel  1  and the parts of the weapon that are rigidly connected with the barrel press the spring mechanism  17  together between the lock head  11  and the lock mount  13  in a correspondingly strong manner so that the lock mount  13  moves forward all the more relative to the lock head  11 ).  
      In this connection, we expressly point out that the spring mechanism  17  works directly or indirectly between the lock mount  13  and the lock head  11  and, thus, can be supported by any part of the weapon that can be made stationary with respect to the lock head  11 .  
      The described process of the relative movement between the lock head  11  and the lock mount  13  first comes to a stop when equilibrium has been created between the spring mechanism  17 , on the one hand, and the inertia of the lock mount  13 , on the other hand, supported as the case may be by the power of the recoil spring  9 . The path of movement is, thus, rather short, since: (a) the shoulders or the arms of the shooter strive to counterbalance the recoil of the weapon, and (b) the recoil effect of the fired cartridge on the weapon (mainly) ends at the latest when the bullet or the shot has left the barrel. (With a shot gun, the share of the recoil is relatively low due to gases that flow out forwards behind the shot charge or the bullet.)  
      After the relative movement stops, the compressed spring mechanism  17  begins to expand again and accelerates the lock mount  13  against the power of the recoil spring  9  backwards in a powerful manner. In the course of its backwards movement, the lock mount  13  unlocks the lock head  11  from the barrel  1  and subsequently carries the lock head  11  forward again. This completes an opening cycle of the loading movements.  
      As mentioned above, due to the lack of an impact, the relative movement of the lock mount  13  forward and over the locking position is relatively more pronounced when a relatively strong cartridge is fired than when a relatively weak cartridge is fired. The unlocking of the weapon, thus, requires more time with a strong cartridge than with a weak cartridge. Since a slower decrease in gas pressure is expected with a stronger cartridge than with a weaker cartridge, the delay in unlocking upon firing of a relatively strong cartridge is advantageous because there is more time available for the drop in gas pressure to occur before unlocking is achieved.  
      When the spring mechanism is more strongly compressed, it throws the lock mount  13  backward in a more powerful manner than when the spring mechanism is only weakly compressed by a weak cartridge. Thus, with a strong cartridge, the opening of the lock head  11  and the extraction of the cartridge shell will occur more rapidly than with a weak cartridge. With shot cartridges, this is harmless in and of itself, since stronger shot cartridges are also more modern cartridges that better withstand stress than weaker cartridges with cardboard shell jackets. But when exceeding or falling short of a specific speed range of the lock mount  13 , the speed framework is abandoned in that, on one hand, we can count on a secure locking function and, on the other hand, we cannot count on reliable extraction. As the case may be, the durability of the weapon may even be endangered.  
      A particularly intense opening of the lock can be expected when the spring mechanism is completely compressed beforehand so that the channels of the spring  17 , (e.g., a spiral spring), sit on top of each other. Then, the opening speed can be increased in an unexpected manner. Additionally, parasitic oscillations can overlay and disrupt the system. The durability of the weapon is also a critical characteristic here.  
      In order to avoid such disruptions and comply with the targeted speed range to the greatest extent possible, it is further recommended that the compression of the spring mechanism counterbalances progressively increasing power.  
      The lower limit of the speed range and, thus, the design of the spring  17 , is selected such that reliable function can still be counted on with weak cartridges and contamination. The power of the spring mechanism does not increase linearly with stress, but rather progressively, and, in such a degree that the spring mechanism cannot be compressed very much more, even with the firing of the strongest cartridges.  
      An optimized spring characteristic can, for example, be attained through a type of disk spring stack. However, it is cheaper and easier to equip the spring mechanism with a powerful spring  17  with a mainly linear power/path characteristic and, additionally, to provide a buffer arrangement  41  that is loaded after the spring  17  has been partially compressed. The spring  17  and the buffer mechanism  41  can be coordinated so that only the spring  17  is strained and expands again when firing weak cartridges, but, when firing a stronger cartridge, the buffer mechanism  41  is also engaged. The buffer mechanism  41  can guarantee the desired, progressive behavior.  
      A buffer mechanism made of at least one batch of elastomer buffers  41  with large hysteresis has proven to be optimal. The batching approach ensures that the buffer mechanism can be adjusted for strong cartridges. Furthermore, elastomer buffers  41  tend to avoid stress transversally and, thus, increase their diameter when subjected to pressure. But, the measurement of the diameter increase is a function of the length of the buffer  41  so that several stacked short buffers  41  increase less in diameter than a single, longer buffer  41 .  
      The hysteresis of the buffers  41  is particularly important. It has the effect that not all of the power introduced into the buffers  41  is fed back to the lock mount  13 . Buffers  41  characterized by hysteresis ensure a decrease and phase shift of the fed-back spring power. Thus, it is possible to reliably comply with the aforementioned speed range, within which the lock can function without incident, even for the strongest cartridges.  
      It is, thus, possible, for example, to fire 12-caliber mixed cartridges, (e.g., different shell lengths such as ca. 70-mm- and 76-mm-long cartridges) without incident. Through the simple adjustment of the spring  17  and the buffer device  41 , cartridges of the 12/65 or 12/89 caliber can also be fired in a mixed manner, if this is not otherwise possible with a standard calibration.  
      In a common, prior art, semi-automatic weapon with a lock head and a lock mount, the lock mount moves backwards when being unlocked, while the lock head remains stationary. The striker/firing pin remains seated in the lock mount so that the striker/firing pin can reach the detonator cap of a cartridge when the weapon is not completely locked. In order to prevent this premature striking of the cartridge, the weapon illustrated herein has a connecting link. The connecting link  39  is supported in the locked state on the lock head  11 . The spring mechanism  17  is supported on the connecting link  39 . The connecting link  39  is transported by the lock mount  13  during its recoil so that the unlocked lock head  11  is not directly burdened by the spring mechanism  17 , at least right after unlocking.  
      Furthermore, in the illustrated example, the striker/firing pin  19  is directly attached to the lock head  11 .  
      In the prior art, the cartridge could also be fired whenever the lock head engaged the cartridge, regardless of whether the lock was locked or unlocked.  
      In order to prevent firing when the lock head  11  is unlocked, the illustrated example employs a locking block  25  that is attached to the lock head  11 . When the locking block  25  is located in a locked position, the striker/firing pin  19  may strike the cartridge. But, when the locking block  25  is in an unlocked position, the locking block  25  blocks the striker/firing pin  19  in a secluded, inoperative position such that a cartridge may not be fired. In other words, the locking block  25  functions like a safety, as the trigger can only fire a cartridge when the lock head  11  is locked.  
      In the illustrated example, the locking block  25  has a taper  33  or camming surface with which it places the striker/firing pin  19  in the inoperative position during the transition time in which the lock head  11  moves from the locked to the unlocked position. For example, if the striker/firing pin  19  gets stuck in a detonator cap as a result of a cartridge failure, then the striker/firing pin  19  is disengaged by the movement of the locking block  25  during unlocking and is placed in an inoperative position.  
      The locking block  25  can be moved transversely to the bore axis  37  in the lock head  11  into and out of the locked position. Moreover, the locking block  25  passes through the lock head  11 . When in the locked position, the locking block  25  engages in a recess  5  in a component that is constructed as one piece together with the barrel  1  or is otherwise affixed to the barrel  1 . This engagement preferably takes place at three locations that are distributed approximately equidistantly over the perimeter of the component. Particularly with a shot gun, a generous over-dimensioning of the recess  5  and the locking block  25  is possible due to the cartridge size. The locking block  25  is preferably slightly beveled in the section that reaches into the recess  5  so that a gentle locking (above all at high housing tolerances) and unlocking is always possible.  
      The lock mount  13  of the illustrated example is structured in a longitudinally moveable manner and is located below the lock head  11  opposite the recess  5 . The locking block  25  has a front and a rear base board  8 . The lock mount  13  has front and rear driving rods  55 ,  57 . During recoil, the front driving rods  55  of the backward moving lock mount  13  hit the front base board  8  of the locking block  25  in order to pull it out of the recess  5 . During the closing movement, the rear driving rods  57  of the lock mount  13  hit the rear base board  8  of the locking block  25  in order to press/cam it into the recess  5 . At least one each of the front or rear base boards  8  and the driving rods  55 ,  57  are beveled.  
      When the lock head  11  is locked, then the lock mount  13  can be moved freely over the position that it takes on after locking is complete. If the lock mount  13  moves backward from this position, then it pulls the locking block  25  out of the recess  5  after covering a more or less large play distance and then carries the lock head  11  with it. The size of the play between the base boards  8  of the locking block  25  and the driving rods  55 ,  57  of the lock head  11  is not important. It is only important that the base boards  8  fit in the opening  53  between the driving rods  55 ,  57  in the lock mount  13 . Thus, a simple and less exact production is possible. Further, inexact parts or spare parts can be installed without further adjustment.  
      The example weapons disclosed herein can, for example, be used for long-barreled machine pistols or for semi-automatic rifles. In particular, the disclosed system is suitable for a semi-automatic shot gun. Through suitable adjustment of power, suitable construction of the spring mechanism  17 , and proper selection of the dimensions of the lock mount  13 , a specialist can create a semi-automatic shot gun that processes various types of munitions without incident, and that only requires a small portion of the production costs of prior art semi-automatic shot guns.  
      From the foregoing, persons of ordinary skill in the art will further appreciate that the disclosed automatic and semi-automatic weapons (e.g., a semi-automatic shot gun) are simple, robust and undemanding with respect to munitions, and, thus, are universally useful. They may be used as a hunting weapon even in underdeveloped areas where one relies on various munitions. They may also be a valuable police or military weapon (e.g., as emergency armament in military airplanes, etc). In particular, such a weapon is particularly useful: (a) where the weapon is used after a long period of non-use, without being able to be subjected to prior examination and cleaning, (b) where one cannot be picky with respect to munitions, and/or (c) where the costs of the weapon cannot be too high.  
      Although certain example methods and apparatus have been described herein, the scope of coverage of this patent is not limited thereto. On the contrary, this patent covers all methods, apparatus and articles of manufacture fairly falling within the scope of the appended claims either literally or under the doctrine of equivalents.