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(11) | EP 3 569 972 A1 |
| (12) | EUROPEAN PATENT APPLICATION |
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| (54) | CARTRIDGE ARRANGEMENT FOR INCREASED MUZZLE VELOCITY OF GUNS |
| (57) The present invention relates to a cartridge arrangement (9) for guns comprising
a casing (11) holding a propellant and a projectile (10) in a projectile holding position,
wherein the casing (11) comprises a holding section interacting with a contact section
of the projectile (10) and the holding section forms a releasable positive lock and/or
a material bond with the projectile (10), providing an initial resistance against
propulsion of the projectile (10) and thereby a delay of the projectile's (10) exit
out of the projectile holding position and an increased barrel velocity after releasing
the projectile (10) from the casing (11).
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SUBJECT OF THIS INVENTION
[0001] The present invention relates to a cartridge arrangement for an increased muzzle velocity of guns.
TECHNICAL BACKGROUND
[0002] Generally, before a firearm is fired, the cartridge, the chamber holding the cartridge and the barrel are all at rest or ambient pressure. When the primer is struck by the firing pin and is thereby ignited, a slight over-pressure is created in the cartridge case's primer pocket, which is called primary ignition. Then, the burning primer granules ignite the powder in the cartridge case, which leads to a further increase in cartridge case pressure and consequently to an increase in chamber pressure. This is called secondary ignition. The cartridge case flattens against the chamber wall leading to a swelling event against the chamber wall sealing gases from exiting rearward. The burning powder acts as a pressure generator. As long as the chamber volume is constant, the pressure goes up at a fixed rate depending on the burn rate of the burning powder.
[0003] As soon as the chamber volume starts to increase due to the release of the projectile and its entry into the barrel, the pressure buildup either
- a) overcomes the increase in volume and keeps rising,
- b) remains equal during the increase in volume, or
- c) is unable to keep up with the increase in volume and sinks.
[0004] With a) the pressure increases, with b) the pressure plateaus, and with c) the pressure goes down. In the early stages of powder ignition, the pressure generator (burning powder) overcomes the increase in volume thus the pressure increases. However, as the pressure generator slows down and the expanding volume nullifies the pressure increase, there is a pressure plateau. With further volume expansion and decreasing burning power of the pressure generator (burning powder), the pressure goes down.
[0005] It is difficult to assess when the projectile starts to move towards the barrel during the burning process. A precise evaluation of elapsed burning time versus increase in pressure is needed for this task, but this is often further complicated by imprecise definitions of which pressure is being measured; i.e. cartridge case vs. chamber vs. barrel pressure. Usually, all are included under chamber pressure.
[0006] Furthermore, the distinction between the two pressure generators (primer and cartridge powder) is rarely made. It is known that the pressure generated by the primer alone has pushed projectiles into and out of barrels, which results in a disadvantageous muzzle velocity. There are a number of variables associated with a possible early entry of the projectile into the barrel, such as the caliber, the type of the gun (e.g. pistol vs. rifle), or the type of primer.
[0007] Even though the internal ballistics may vary with these variables, some generalizations can be made. With large rifle calibers, a projectile starts to engage the land and grooves of the barrel during the very early buildup of cartridge case/chamber pressure (CCCP). The base and boat tail of the projectile are still within the neck of the cartridge case when full powder ignition takes place and the projectile is in the first third of barrel as pressure increases. Literature states that the entry into the rifle normally occurs between 3,000 to 5,000 psi CCCP, while the pressure is still rising, which is inferior to a theoretical later release at a higher CCCP, resulting in a higher muzzle velocity. Higher muzzle velocities have a positive effect on the external ballistic properties of a projectile and are therefore strived for.
[0008] An object of the present invention is to supply an improved cartridge arrangement to at least partially overcome the above-mentioned drawbacks.
SUMMARY OF THE INVENTION
[0010] According to a first aspect of the present invention, a cartridge arrangement for guns is provided, which comprises a casing holding a propellant and a projectile in a projectile holding position, wherein the casing comprises a holding section interacting with a contact section of the projectile and the holding section forms a releasable lock, specifically a positive lock and/or a material bond with the projectile. This provides an initial resistance against propulsion of the projectile and thereby a delay of the projectile's exit out of the projectile holding position and an increased barrel velocity after releasing the projectile from the casing is provided.
[0011] The cartridge arrangement can be realized in a way that the initial resistance against propulsion is great enough to hold the projectile in the projectile holding position within the casing until an optimal chamber pressure is reached, upon which the initial resistance against propulsion is overcome by a chamber pressure force acting on the projectile and forcing it into the barrel. This results in a higher muzzle velocity.
[0012] As the cartridge arrangement usually comprises a primer to ignite the propellant upon firing of the gun, the increased resistance against propulsion can consequently also prevent the projectile from being pushed into the barrel only by the chamber pressure created by the primer, since this could have a negative effect on the muzzle velocity of the projectile.
[0013] The solution according to the present invention contributes to eliminate any remaining pressure difference between the chamber pressure and the ambient pressure immediately after the projectile fully leaves the muzzle of the gun. Furthermore, this can be achieved according to the present invention by dimensioning the initial resistance against propulsion for specific gun types and calibers among other things.
[0014] Further aspects and features are obvious for someone skilled in the art in view of the dependent claims, the drawings and the subsequent description of embodiments.
SHORT DESCRIPTION OF THE FIGURES
[0015] Embodiments of the present invention will now be exemplified with referrals to the attached Figures, of which
Fig. 1 shows a graph mapping a chamber pressure buildup over time according to the present invention;
Fig. 2a and 2b show a first embodiment of the present invention;
Fig. 3a shows the cross-section A-A of Fig. 2a;
Fig. 3b shows the cross-section E-E of Fig. 2b;
Fig. 4a and 4b show a second embodiment according to the present invention;
Fig. 5a shows the cross-section B-B of Fig. 4a;
Fig. 5b shows the cross-section F-F of Fig. 4b; and
Fig. 6 shows a third embodiment of the present invention.
DESCRIPTION OF EMBODIMENTS
[0016] Prior to a detailed description of the embodiments according to Fig. 1 to Fig. 6, some general comments are provided in the following regarding the embodiments.
[0017] According to one aspect, the present invention provides a cartridge arrangement, wherein the contact section of the projectile comprises an indentation section of a projectile surface area. This indentation can be formed after the projectile has been put in the projectile holding position and it can comprise spot indentations and/or circumferential indentations (either complete and/or sectional).
[0018] According to a further aspect, the present invention provides a cartridge arrangement, wherein the holding section of the casing comprises a crimp section, which extends into an inner area of the contact section of the projectile resulting in the initial resistance against propulsion. The crimp section can be formed with the projectile in the projectile holding position so that the crimped area of the casing reaches inside the indentations of the projectile, thus forming a positive lock.
[0019] The corresponding indentations(s) to the crimp section(s) can also be formed by the crimping process.
[0020] According to a further aspect, the present invention provides a cartridge arrangement, wherein the indentation section of the projectile surface area comprises a groove along a circumference of the projectile surface area providing the inner area of the contact section to receive the crimp section of the casing.
[0021] To adjust the holding force it is also possible to arrange more than one holding groove spaced apart in a longitudinal direction. Such holding grooves can also be combined with several crimp sections. Several holding grooves may also serve to provide improved sealing properties, which keep the propulsion gas in the casing for a longer time.
[0022] According to a further aspect, the present invention provides a cartridge arrangement, wherein the indentation section and the crimp section form the releasable positive lock and are dimensioned in a way that the initial resistance against propulsion resulting from the releasable positive lock is equal to such a resistance that allows for an improved firing chamber pressure.
[0023] According to a further aspect, the present invention provides a cartridge arrangement, wherein the material bond comprises a soldering joint and/or a weld joint between the projectile and the casing. The soldering joint can be realized by inserting soldering material between the projectile and the casing into a soldering contact area. The soldering contact area can be configured and defined be a circumferential joint element of the casing reaching towards the inside of the casing and thereby forming a stopping element for the soldering material between the casing and the projectile. A precise soldering joint can thereby be attained, which can result in the same (consistent and adjustable) initial resistance against propulsion that leads to the optimal muzzle velocity as in the case of the positive lock between the projectile and casing.
[0024] A weld joint can be realized either by weld spots and/or by a circumferential weld between an open front end section of the casing and the projectile in the projectile holding position. The weld joint can also be dimensioned in a way that an initial resistance against propulsion is provided, which results in the optimal muzzle velocity.
[0025] According to a further aspect, the present invention provides a cartridge arrangement, wherein the material bond comprises a soldering joint and/or a weld joint between the projectile and the casing.
[0026] The soldering joint can be realized by inserting soldering material between the projectile and the casing into a soldering contact area. The soldering contact area can be configured and defined be a circumferential joint element of the casing reaching towards the inside of the casing and thereby.
[0027] According to a further aspect a positive lock and a material bond with the projectile can be combined. E.G. one or more crimp sections can be combined with one or more welding and/or soldering sections.
[0028] According to an aspect of the present invention, the invention provides a process for the production of a gun cartridge comprising a casing with an open front end section and a closed rear end section, a propellant, and a projectile, wherein the propellant is placed within the casing through the front end section towards the rear end section and the projectile is placed within or partly within the casing in a projectile holding position at the open front end section and a positive lock between the cartridge and the projectile is formed through crimping an outer surface area of the cartridge/casing with the projectile in the cartridge holding position, thereby also crimping (forming) an outer surface area of the projectile.
[0029] Now, returning to Fig. 1, this figure shows a diagram of the chamber pressure p over time t within the chamber of a gun with a cartridge arrangement according to the present invention. The dashed-dotted line 1 shows a chamber pressure buildup according to the present invention, while the solid line 2 depicts a chamber pressure buildup in traditional firearms, where the present invention is not implemented. The dashed line 3 visualizes the initial increase in chamber pressure in traditional firearms (without implementation of the present invention) due to the firing of the primer and the discontinuous ignition of the burning powder. The dotted line 4 shows the respective initial increase in chamber pressure for cartridge arrangement according to the present invention.
[0030] The solid line 2 and the dashed-dotted line 1 respectively, begin once the burning powder is fully ignited. The dashed line 3 of a traditional cartridge arrangement and the dotted line 4 of firearms with the present invention implemented start to differ as soon as the chamber pressure is equal to a projectile release pressure 5, which forces the projectile out of its projectile holding position and into the barrel in traditional firearms, yielding a gradual increase in chamber volume resulting in a slower rate of chamber pressure buildup for traditional firearms. For cartridge arrangement according to the present invention, the chamber pressure increases faster and the projectile's exit out of the projectile holding position is impeded until the optimal projectile release chamber pressure 6 is reached. The sudden increase in chamber volume results in a bend of the dashed-dotted line 1. Because the projectile is released from its projectile holding position at a higher chamber pressure compared to traditional firearms, the projectile has a higher and therefore better muzzle velocity.
[0031] The impeded release of the projectile out of the projectile holding position according to the present invention results in a faster pressure buildup of the burning powder. This has the effect that more of the available burning powder is burned and converted into kinetic energy of the projectile while the projectile is within the barrel, minimizing and/or eliminating any pressure differences between the chamber and the ambience. Traditional firearms without the present invention exhibit a pressure differential 7 between the chamber pressure and ambient pressure after the projectile fully exits the muzzle. This results in losses of potential energy, which cannot be transformed into kinetic energy of the projectile.
[0032] Fig. 2a shows a cartridge arrangement 9 according to a first embodiment of the present invention. The projectile 10 is shown here in its projectile holding position within the casing 11. In this embodiment, the contact section of the projectile 10 is formed as a groove 12 and the holding section of the casing 11 is a circumferential crimp 13. The crimp 13 reaches inside the groove 12, and the groove 12 is therefore not directly visible in the figure (indicated by the arrow). Fig. 2b is a close-up view of Fig. 2a and shows the circumferential crimp 13 in more detail.
[0033] Fig. 3a shows the cross-section A-A of Fig. 2a. The cross-section of the projectile 10 shown here lies within the groove 12 of the projectile 10, which is covered by the circumferentially crimped casing 11. Fig. 3b shows the cross-section E-E of Fig. 2b. Here, the projectile 10 is visible with its groove being covered by the casing 11 and its circumferential crimp 13.
[0034] Fig. 4a and Fig. 4b show a second embodiment according to the present invention. In this embodiment, the projectile's 10 contact section is formed as two spot indentations 14 and the casing's 11 holding section is formed as two spot crimps 15 that reach inside the two spot indentations 14. Alternatively, another embodiment of the present invention could incorporate any number and/or forms of indentations and/or crimps.
[0035] Fig. 5a shows the cross-section B-B of Fig. 4a. The cross-section of the projectile 10 lies within the plane of the two spot indentations 14, where the two spot crimps 15 of the casing 11 reach inside. Fig. 5b shows the cross-section F-F of Fig. 4b. The cross-section of the projectile 10 is again chosen to lie within the plane of the two spot indentations 14. Again visible here is the casing 11 with its spot crimps 15.
[0036] Fig. 6 shows a third embodiment of the present invention, which is visualized here as a cross section. In this embodiment the projectile's 10 contact section is formed as a groove 12 around its circumference and the holding section of the casing 11 is formed by flanging the front end section 16 of the casing 11 so that the flanged section 17 of the casing 11 reaches inside the groove 12 Alternatively, the contact section of the projectile could also be formed as spot indentations and the holding section of the casing could be formed as spot flanges that reach inside the spot indentations.
[0037] The first, second and third embodiments can also be realized together in any combination (first, second, and third embodiment; first and second embodiment; first and third embodiment; and second and third embodiment).
[0038] Further variations and embodiments of the present invention are obvious for someone skilled in the art within the scope of the claims.
REFERENCE SIGNS
[0039]
- p
- chamber pressure
- t
- time
- 1
- dashed-dotted line (chamber pressure buildup according to the present invention)
- 2
- solid line (chamber pressure buildup in traditional firearms)
- 3
- dashed line (initial increase in chamber pressure of traditional firearms)
- 4
- dotted line (initial increase in chamber pressure according to the present invention)
- 5
- projectile release pressure (traditional firearms)
- 6
- optimal projectile release chamber pressure according to the present invention
- 7
- pressure difference of traditional firearms
- 8
- pressure difference according to the present invention
- 9
- cartridge arrangement according to the present invention
- 10
- projectile
- 11
- casing
- 12
- groove
- 13
- circumferential crimp
- 14
- spot indentations of the projectile
- 15
- spot crimps of the casing
- 16
- front end section
- 17
- flanged section of the casing
1. Cartridge arrangement (9) for guns comprising a casing (11) holding a propellant and
a projectile (10) in a projectile holding position, wherein the casing (11) comprises
a holding section interacting with a contact section of the projectile (10) and the
holding section forms a releasable positive lock and/or a material bond with the projectile
(10), providing an initial resistance against propulsion of the projectile (10) and
thereby a delay of the projectile's (10) exit out of the projectile holding position
and an increased barrel velocity after releasing the projectile (10) from the casing
(11).
2. Cartridge arrangement (9) according to claim 1, wherein the contact section of the
projectile (10) comprises an indentation section (14) of a projectile surface area.
3. Cartridge arrangement (9) according to claim 1 or 2, wherein the holding section of
the casing (11) comprises a crimp section (15), which extends into an inner area of
the contact section of the projectile (10) resulting in the initial resistance against
propulsion.
4. Cartridge arrangement (9) according to claim 2 or 3, wherein the indentation section
(14) of the projectile surface area comprises a groove (12) along a circumference
of the projectile surface area providing the inner area of the contact section to
receive the crimp section (15) of the casing (11).
5. Cartridge arrangement (9) according to claim 2, 3 or 4, wherein the indentation section
(14) and the crimp section (15) form the releasable positive lock and are dimensioned
in a way that the initial resistance against propulsion resulting from the releasable
positive lock is equal to an optimal resistance, which is overcome upon reaching an
optimal firing chamber pressure (6).
6. Cartridge arrangement (9) according to claim 1, wherein the material bond comprises
a soldering joint and /or a weld joint between the projectile (10) and the casing
(11).
7. Process for production of a gun cartridge comprising a casing with an open front end
section and a rear end section, a propellant, and a projectile, wherein the propellant
is placed within the casing towards the rear end section and the projectile is placed
within or partly within the casing in a projectile holding position at the open front
end section and a positive lock between the cartridge and the projectile is formed
through crimping an outer surface area of the cartridge with the projectile in the
cartridge holding position, thereby also crimping an outer surface area of the projectile.