KR20240022498A - Ammunition casing with steps within deep shell grooves - Google Patents

Abstract

The casing 720 for the ammunition cartridge includes a sleeve portion 722 and a base portion 724. The casing may be two-piece, where the base portion is secured to the sleeve portion by a nipple 728 with flared ends. The base portion includes a shell groove 746 extending longitudinally from the flange 755. Preferably, the curved shell groove is deeper than a conventional shell groove, and thus the casing weight is reduced. The shell groove has a step 750 adjacent to the flange to limit the inward movement of the lip 94 of the hook 92 of the bolt 90 of the firearm. Alternatively, casing 1020 may be a one-piece casing where the base and sleeve are integrated.

Description

Ammunition casing with steps within deep shell grooves

The present invention relates to ammunition for firearms, and in particular to the construction and use of cartridges and casings containing such ammunition.

US Pat. No. 9,939,236 to Drobockyi et al. and US Pat. No. 10,260,847 to Viggiano et al. describe, among other things, a two-piece casing consisting of a sleeve and a base. The sleeve, preferably made of magnetically attractive stainless steel, has a recessed portion for containing gunpowder and has an opening at its first end for storing the projectile. At the second, opposite end, the sleeve has an integral nipple disposed within the central passageway of the base. The end of the nipple flares at a shoulder within the passage. For example, when applied to 9mm ammunition, the base may be formed of aluminum alloy and the cannelure may follow the well-known cannelure. Casings made according to the teachings of the '236 and '847 patents offer advantages over conventional forged brass casings, including lighter weight, increased powder volume, and magnetic attraction.

As with the 7.62×51mm NATO ammunition, it has been found advantageous to fabricate the base from a high-strength steel alloy, especially when the casing is subject to high gunpowder deflagration pressures compared to those associated with 9mm ammunition. Compared to using aluminum alloy, this has the undesirable effect of increasing the weight of the casing. U.S. Patent No. 10,697,743 to Viggiano et al. describes a casing for ammunition characterized by having a deep curved cross-section groove compared to the combination of cylindrical and truncated conical portions of the groove of familiar ammunition. Figure 3 of this application shows a partial cross-section of a casing with shell grooves of U.S. Pat. No. 10,697,743. Special shell grooves reduce the weight penalty that occurs when using another material heavier than steel or aluminum, without compromising the performance of the casing.

During extensive development testing of cartridges comprised of a two-piece casing featuring the deep cartridge grooves described above, jamming occasionally occurred in the firearm chamber of the casing used when certain firearms were fired repeatedly at high speeds. The object of the present invention is to avoid problems of this kind.

The object of the present invention is to provide a grooved firearm that reduces the weight of the article (compared to common ammunition with the familiar groove configuration) while providing a minimum propensity for jamming in automatic repeating firearms with high rates of fire. Casings and cartridges are provided.

In an embodiment of the invention, an ammunition cartridge has a casing that includes a sleeve and a base. The sleeve and base may be one piece or may be separate parts held together as a two-piece casing. The sleeve is this part of the casing with an opening that contains the gunpowder and stores the projectile during use. The sleeve adjacent to the base is typically cylindrical. The base proximal end includes a flange formed for gripping by the hook of a firearm bolt, as in a conventional casing, to enable extraction of the empty casing from the firearm chamber. The casing has shell grooves extending from the distal surface of the flange to the vicinity of the sleeve. The shell groove is deeper than that of conventionally known ammunition, providing the benefit of weight reduction.

A circumferentially continuous step, which may also be referred to as a ledge, is in the shell groove adjacent to the flange. The step limits how far the lip at the hook end of the bolt can fit into the shell groove. The step may have a cylindrical surface or, for example, a surface that is slightly curved inward towards the casing longitudinal axis with increasing distance from the flange. The steps may be spaced apart from the flange by grooves. Preferably, the shell groove has a portion extending from the inside of the step toward the center line of the casing, preferably in a curved shape. and a continuous portion extending from said portion conically or curved outward to a cylindrical surface of the base having a diameter equal to the diameter of the sleeve. The step avoids any tendency for the tip of the firearm's bolt hood to come into wedging contact with the curved portion of the shell groove. In other embodiments, the shell grooves may be cylindrical and then curved from the steps.

During use, when the bolt of a typical firearm engages the proximal end of the cartridge's casing, the lip at the end of the pivotable hook portion of the bolt enters the casing groove, but its inward movement is limited by the step of the casing casing groove. The cartridge of the invention includes the casing of the invention having a projectile disposed at the mouth of the sleeve, a quantity of gunpowder within the sleeve, and a primer within the proximal end of the passageway. The object of the present invention is achieved; Lighter weight deep groove cartridges fire from repeating firearms without jamming.

The above and other objects, features and advantages of the present invention will become more apparent from the following description of preferred embodiments and the accompanying drawings.

1 is an exploded perspective view of the portion of a prior art cartridge that is contacted by the bolt of an automatic firing weapon.
Figure 2, related to Figure 1, is a partial side view of the casing of a prior art cartridge, showing how the flanges of the casing are engaged by the hook portion of the bolt.
Figure 3 is a partial cross-sectional view of a two-piece casing with deep curved shell grooves.
4A, 4B and 4C show that the engagement of the base of the casing, shown in cross section, with the bolt of the firearm, shown partially in phantom, initially causes the hook of the bolt to move radially outward from its home position. Here are related sequential drawings showing how to do it. Then, due to another movement of the bolt, Figure 4C shows how the lipped end of the spring-loaded hook moves radially inward to grip the flange of the casing.
Figure 5 is a side view, shown partially in cross section, of the base of the casing with a curved shell groove when mated with a bolt and gripped by the hook of the bolt;
Figure 6 is a partially cut away side view of a two-piece casing having curved shell grooves with circumscribed steps that limit radial inward movement of the ends of the hooks.
Figure 7 is a side view of a portion of a casing similar to the casing of Figure 6, showing the casing engaged with a bolt of a firearm. Internal details of the bolt are shown in partial cross section.
Figure 8 is a side view of a portion of a casing having stepped grooves spaced apart from the inner (distal) face of the flange.
Figure 9 is a side view of a portion of a casing having stepped shell grooves with radially oriented surfaces curved toward the longitudinal axis.
Figure 10 is a side view of a portion of a single piece casing with shell groove steps.

Reference herein to a cartridge (sometimes referred to as a “round”) is generally a reference to a piece of ammunition suitable for firing from a firearm. A cartridge includes a casing, gunpowder within the casing, a projectile, and a primer. Well known casings have shell grooves, radially recessed circumscribed regions, or grooves running distally from the casing flange at the proximal end of the casing/cartridge. The proximal end includes a central recess. The opposing distal end of the casing includes a casing inlet. A cartridge prepared for firing with a firearm contains gunpowder inside a recessed portion of the casing, a projectile stored inside the mouth end, and a primer set in a central recess in the proximal end.

Although most embodiments of the invention herein are described in relation to a two-piece casing, other embodiments are in the form of a one-piece casing. A two-piece casing embodying the present invention includes a first part, referred to as a sleeve, formed to receive a projectile that holds gunpowder and closes the entrance, and a joined second part, called a base, that is formed to store a primer. The sleeve portion and base portion may be formed separately and attached to each other as described in U.S. Patent Nos. 9,625,241 (Neugebauer), 9,939,236 (Drobockyi et al.), 10,260,847 (Viggiano et al.), and 10,697,743 (Viggiano et al.). there is. The disclosures of the above patents are hereby incorporated by reference in their entirety. In another embodiment of the invention, the sleeve portion and base portion may be integral with each other (such as a conventional forged brass casing).

In the familiar prior art and casings of the present invention, a circumscribed groove or shell groove is located between the flange and sleeve portion of the casing. The shell groove allows the hook of the firearm's bolt to extract the casing from the firearm's chamber after the round has been fired. To inform you about the functions and benefits of the present invention, it will first be described herein to understand the process of placing a round in the chamber of a firearm and removing it after firing.

1 is a semi-schematic exploded view of the end of a firearm bolt 90 in combination with a prior art casing 20. Figure 2 shows the same casing in engagement with bolts. Figure 3 shows the improved shell groove described in U.S. Pat. No. 11,262,172. Figures 4A, 4B and 4C sequentially show how the bolt approaches the base of the cartridge in preparation for pushing the cartridge into the "home", i.e. the chamber of the firearm (not shown).

1 and 2, the casing 20 includes a sleeve portion 67 and an integrated base portion 24. The casing 20 includes cartridge grooves 46 of a typical, well-known type, such as in the familiar prior art 7.62×51 mm NATO cartridge. The shell groove 46 includes a circumscribed groove or channel on the outside of the casing. The shell groove has a longitudinal dimension (also referred to as width) extending from the flange to a point near the sleeve, at which point the base has a nominally constant diameter equal to the diameter of the adjacent portion of the sleeve. The shell groove 46 is characterized as follows: first, at the proximal end by surface 61, which is the distally facing surface of the flange 55. Second, in the middle part by a continuous cylindrical surface (63). Thirdly, at the distal end by a continuous conical surface (65) which both runs outward to meet the cylindrical surface (67) of the base adjacent to the sleeve portion of the casing. Illustratively, the thickness of flange 55 may be approximately 1.23 mm and the diameter of surface 63 may be approximately 10.3 to 10.4 mm.

Referring particularly to FIGS. 1 and 7 , a typical bolt 90 includes a hook 92 . The hook includes a shank that pivots around a pin (97). The outermost end of the hook has a lip 94 extending radially inward towards the center line CL of the bolt (which may also be the center line of any casing engaged by the bolt). The lip of the hook drops into the cartridge groove when the face 91 of the bolt mates with the proximal end of the cartridge to force the cartridge into the firearm chamber. When the bolt retracts from the chamber after the cartridge/round has been fired, the hook pulls on the flange of the casing to extract it from the chamber. As shown in Figure 2, when used with a casing having a conventional shell groove, the inwardly facing surface of the end 19 of the lip 94 may rest on the cylindrical surface 63 of the shell groove 46. . And, typically, there will be a small clearance between the shank of the hook and the edge of the flange 55.

When a firearm is configured for repeated or automatic fire, cartridges are magazine-fed or belt-fed into the firearm chamber, within which the bolt is diverted. In a typical firing cycle, the bolt forces a cartridge into the empty chamber of the firearm (not shown). After firing, the bolt retracts, pulling the spent casing from the chamber back into the breech area, from which it is immediately ejected by the bolt's spring-loaded pin 96. Figure 7 shows a cross-section of a portion of the bolt 90 in combination with an exemplary inventive casing 720, which is discussed below. Figures 1 and 7 show various details of the bolt in a somewhat simplified or semi-schematic manner.

Referring particularly to Figures 1 and 7, when a new cartridge is chambered, the bolt moves forward along the longitudinal axis CL to insert the cartridge into the chamber of the firearm. During this process, the casing flange (55) is received within a recess (95) in the bolt face with a flat base surface (91). Pushing the cartridge into the "home" within the chamber causes the casing flange 55 to strike the firearm structure (not shown) surrounding the chamber opening. The bolt is then rotated about the axis CL through a small circumferential angle, thereby locking the bolt by means comprising bolt spline segments 93, whereby the bolt resists the reaction force from the deflagration pressure in the casing. makes it possible. After firing the projectile, the bolt rotates in a direction opposite to the first rotation, simultaneously allowing rearward movement of the bolt and extraction of the casing from the chamber.

To complement the above: When the bolt first contacts the casing portion of the cartridge, the angled terminal end of the lip 94 of the hook 92 causes the free end of the hook to be deflected radially outward. See Figures 4A and 4B. Rotation of the hook about the pin (97) compresses the bolt spring (98). See Figure 7. As the distance between the bolt and the casing continues to decrease, the base of the casing is received within the recess 95 in the face of the bolt; The spring 98 causes the hook to pivot about the pin 97, so that the lip 94 moves radially inward and falls into the shell groove 46. See Figure 4C. The bolt then continues to advance until the cartridge rests in its home position with the firearm chambered. Gas pressure within the firearm's barrel due to gunpowder deflagration both propels the projectile out of the barrel and through channeling within the firearm, causing the bolt to rotationally unlock and move rearward and away from the chamber. As the bolt moves away from the chamber, the hook 92 pulls on the flange 55 and thus pulls the entire now empty casing out of the chamber. Within the recess 95 of the bolt face is an extraction pin 96 which is biased by a spring 99 (the pin is shown in Figure 7 as being pushed inward by contact of the casing with the bolt). When the bolt retracts and pulls the entrance of the casing from the chamber, the spring force release pin pushes the casing and causes the casing to fly out of the recess (95) and from engagement with the hook (92); The spent casing flies upward and laterally into the air from the weapon's chamber. This allows a new cartridge to be introduced into the chamber, so that the load-fire-eject cycle can be repeated. If the used case is not properly blown out of the chamber, there may be a risk of jamming.

Figure 3 is a partial cross-sectional view of a two-piece casing 620 with curved shell grooves according to the casing disclosed in U.S. Patent No. 10,697,743. Casing 620 includes a sleeve 622 secured to a base 624 by a sleeve nipple 628, the ends of which flare against a shoulder within a bore of a passageway running longitudinally through the base. The shell groove 646 includes a flat surface 647 running radially inward from the distal surface of the flange 655; A first portion 649 that first runs inwardly and longitudinally and a second portion 651 that curves outward to meet the cylindrical surface 653 of the base, which has substantially the same diameter as the outside of the sleeve 622. It is defined by a continuous longitudinally extending curved surface containing. All of these surfaces can be referred to as surfaces of rotation.

The minimum diameter of adjacent curved portions 649, 651 is substantially smaller than the diameter of the cylindrical surface 63 of the prior art casing 20 as shown in Figure 2. Therefore, a casing 620 made of steel or another strong metal alloy has the advantage of being lighter in weight compared to the same metal case of the same caliber with a conventionally shaped cartridge groove - the casing can be used, for example, for a NATO 7.62×51mm cartridge. It is strong enough to withstand the high deflagration pressures associated with it. An alternative configuration of a two-piece casing with a base attached to a sleeve may be used, including a casing where third component rivets are used to secure the sleeve and base to each other. An example of this is shown as connecting element 24 in FIG. 3 of Neugebauer's above-referenced patent No. 9,625,241. The casing may alternatively be formed as a one piece casing with shell grooves substantially the same as those described for the two piece casing.

Numerous tests have been performed by firing cartridges containing casing 620 from an automatic repeating firearm. Sometimes bolt jamming was observed. The low incidence of jamming meant that it was difficult to determine the cause. Figure 5 shows the base 624 of the casing 620, to illustrate the never-proven suspicion that jamming may be caused by the degree of wedging of the end 19 of the lip 94 relative to the shell groove at point 59. ) is shown when engaged with the hook 92 of the bolt 90, where the shell groove is curved longitudinally, possibly due to minor manufacturing differences in shape or finish, despite what was thought to be a precision manufacturing process. It starts to connect.

Jamming is eliminated by forming features in the curved shell grooves, which are referred to herein as steps but may also be referred to as ledges. The step inside the casing groove, in the absence of a step, allows the lip of the hook to extend deeper into the casing groove of the present invention, which has a minimum diameter dimension smaller than that characterizing conventional casing grooves, without a wedge, along the center line of the casing. A portion of the circumscribed surface of the shell groove configured to limit radially inward movement of the lip of the facing hook.

6 and 7 illustrate one embodiment of the invention, namely a two-piece casing 720 consisting of a sleeve 722 attached to a base 724 by flared nipples 728. The base 724 has a curved shell groove 746, and there is a step 750 within it. 7 shows a casing 720 held in contact with a bolt 90, with the end 19 of the lip 94 contacting the step 750 and the lip 94 of the hook gripping the distal face of the flange 755. ) is shown.

In use of the present invention, when the base 724 of the cartridge 720 engages the bolt 90, the radially inwardly facing surface of the end 19 of the lip 94 of the hook 92 forms a step 750. , thereby limiting the range of spring-induced radial medial movement of the lip toward the longitudinal axis CL.

One exemplary step for a NATO 7.62 x 51 mm cartridge has a diameter of about 10.3 mm and an axial length of about 0.7 mm (one example step diameter for casing 720 is about the cylindrical surface 63 of a conventional 7.62 x 51 mm round). It may be approximately equal to the diameter (see Figure 2). For reference, in one exemplary casing, the CL axis of the end 19 of the lip 94 of the hook 92 contacts the casing step or cartridge groove (if applicable) of a representative firearm using a 7.62×51 mm cartridge. The direction length is about 1.3mm. For reference, the exemplary casing has a flange diameter of approximately 11.8 mm and a thickness at the outer edge location of approximately 1.23 mm; Both of these dimensions are nominally identical to those that characterize conventional cartridge flanges.

Referring again to Figure 7, in an embodiment of the NATO 7.62 x 51 mm casing, the step prevents the hook underside surface from contacting the circumferential surface of the flange edge. For example, there may be a gap 87 of approximately 0.03 to 0.05 mm between the hook and the flange circumferential surface.

Referring again to Figure 6, in one embodiment of the invention, the step 750 of the casing 720 is cylindrical with a radius less than about a 5.9 mm radius of the flange 755 of a 7.62 x 51 mm cartridge. It is the surface. One exemplary dimension (RA) is about 1 mm. In another embodiment of the same size cartridge, the dimension RA may be between 1 mm and 1.6 mm. As mentioned, the dimension RA is preferably selected such that, for a particular bolt and hook configuration, the surface facing the centerline of the hook body does not contact the outer surface of the flange. In one embodiment of the invention configured for use with a 7.62 x 51 mm cartridge, the flange 755 axial length (thickness) LB is about 1.3 mm; The step axis length (also referred to as step width) (LA) may be about 0.6 mm to 1.27 mm. Steps with slightly smaller or slightly larger axial lengths may be used. Since the purpose of the deep shell grooves is to reduce the weight of the base, it is preferred to minimize the step shaft length. However, if it is desirable for the entire radially facing surface of the bolt lip to be in contact with the shell groove circumscribed surface, it will be desirable for the step length to be close to the length of the lip parallel to the centerline axis CL.

The length LC of the exemplary shell groove 746 is approximately 3 mm, including the axial length of the step, as indicated. Accordingly, one exemplary step of 0.6 mm to 1.27 mm in length would be about 20 to about 42 percent of the 3 mm length of an exemplary shell groove.

8 illustrates another embodiment of the invention, i.e., a base where steps 850 are spaced by grooves 851 from a distally facing annular surface 861 extending inwardly from the distal annular surface of flange 855. (824) is shown. Dimension LD in Figure 8, the distance from the flange distal face to the distal edge of the step, may be the same as dimension LA in Figure 6. The configuration of base 824 may therefore provide a step that is functionally equivalent to step 750 (shown in FIG. 6) of casing 720, with a lower weight of the casing. In embodiments of the invention, the step may not be a smooth cylindrical surface as long as it is functionally equivalent with respect to restricting the inward movement of the hook. For example, the step may include a plurality of closely spaced circumscribed ribs. As another example, Figure 9 shows a casing 920 including a base 924 with a step 950 having an outwardly facing surface that curves longitudinally inward; The curvature is less than that which would result in the above-mentioned assumed wedging of the hook.

In embodiments of the invention, it is preferred that the shell grooves are continuous curved surfaces, as described in U.S. Pat. No. 10,697,743, although something approximating a curve - for example, a series of continuous conical surfaces - is an equivalent. It is within the scope of the present invention.

Figure 10 shows one embodiment of a one-piece casing 1020 with uncurved shell grooves containing steps. Except for the steps, casing 1020 has shell grooves 1065 that are generally similar to those that characterize the prior art cartridge brass casing 20 of FIG. 2 . Casing 1020 includes flange 1055; Casing groove 1046 includes an annular portion extending inwardly from the annular distal surface of flange 1055, a continuous cylindrical portion 1063, and a continuous outwardly extending conical portion. Casing 1020 includes cylindrical steps 1050 having a diameter consistent with that described above with respect to casing 720. The step diameter and length dimensions and step variations (e.g., adjacent grooves and/or longitudinal curved surfaces) previously described for casing 720 may be used in one example casing 1020.

In one embodiment of the one-piece casing 1020, when the minimum diameter of the casing groove cylindrical portion 1063 is substantially smaller than the diameter of the casing groove of a comparable prior art casing, the material of the casing 1020 is used to form the sleeve portion. It needs to be sufficiently formable to form and strong enough to withstand the deflagration pressures applied to the base. The viability of this casing 1020 depends on how large the shell grooves are, what the deflagration pressure is, and what material is selected. A two-piece casing with shell grooves formed as shown in casing 1020 is within the scope of the present invention. The advantage of a two-piece casing over a one-piece casing is that the metal of the sleeve can be selected primarily for formability and the metal of the base can be selected primarily for strength.

Another way to characterize one embodiment of the casing of the invention is as follows: the casing includes a central longitudinal axis, a base portion having a flange at the proximal end of the casing, and a sleeve portion having an inlet formed to receive a projectile. and the entrance is at the distal end of the casing. The base portion includes a first annular side of the flange that faces proximally and surrounds a recess formed to receive the primer. The shell groove extends distally from the opposing second annular side of the flange to near where the base portion mates with, or is integral with, the sleeve portion. The shell groove consists of the following surface portions surrounding a central longitudinal axis:

(a) a first distally facing annular portion, the first annular portion being coplanar with the distally facing surface of the flange;

(b) a second shell groove portion (also referred to as a stepped portion) adjacent to or spaced from the first annular portion by a groove, the stepped portion extending longitudinally and having a diameter less than the outer diameter of the flange, The second shell groove portion;

(c) adjacent to the stepped portion and (i) running inward toward the casing centerline along a plane or curve from the stepped portion, and then (ii) longitudinally cylindrically or curved in the direction from the stepped portion to the distal end of the casing. As a third shell groove portion extending to; the third shell groove portion having a lower portion having a diameter smaller than the diameter of the second shell groove portion; and

(d) a fourth groove surface portion adjacent to a third groove surface portion extending curved or conical away from the centerline axis to the base to a cylindrical portion of the base having nominally the same diameter as the adjacent sleeve.

The casing just described may be a one-piece casing, or a two-piece casing consisting of a sleeve attached to a base.

One embodiment of the invention includes a method of firing a projectile from a cartridge in a firearm, the method comprising: (a) forming a cartridge comprising a casing as described above, wherein the primer is placed in a recess at the proximal end of the base portion; the forming step, wherein a quantity of gunpowder is contained within the sleeve portion and a projectile is secured within the inlet of the sleeve portion; (b) pushing the cartridge into the chamber of the firearm by bringing the proximal end of the cartridge's casing into contact with the face of the bolt of the firearm, wherein the lip at the end of the movable hook portion of the bolt gasses the casing flange and , the pushing step, wherein the lip is in contact with a step of the base of the casing; (c) causing the gunpowder in the sleeve portion to deflagrate by the firing pin of the bolt, thereby discharging the projectile from the casing portion entrance; and (d) then pulling the casing from the chamber of the firearm by the bolt and hook.

The invention, with its explicit and implicit modifications and advantages, has been described and illustrated in several embodiments. This embodiment should be considered illustrative and not restrictive. Any use of words such as “preferred” and variations suggests features or combinations that are desirable but not necessarily required. Accordingly, embodiments lacking any such preferred feature or combination may be within the scope of the following claims. Those skilled in the art may make various changes in the form and details of the described embodiments of the invention without departing from the scope of the claimed invention.

Claims (9)

A casing for ammunition used in a firearm, comprising:
The casing has a longitudinal centerline, a proximal end having a recess formed to receive a primer, and an opposing distal end including an opening for receiving and storing a projectile, the casing containing a quantity of gunpowder. a sleeve portion for storage, the sleeve portion having a distal end characterized by the inlet and an opposing proximal end extending longitudinally with a cylindrical outer surface having an associated diameter; A distal end characterized by a cylindrical portion that tightly mates or is integrated with the proximal end of the sleeve portion, a first side annular flange surface forming at least a portion of the proximal end of the casing and an opposing second side annulus facing the distal end. a base having a proximal end characterized by a flange having a flange surface, the base further characterized by a casing groove located between the flange and a distal end of the base, the casing groove being directed distally and a first shell groove surface portion including at least a portion of a second side annular flange surface; a second casing groove surface portion adjacent to or spaced from said first casing groove surface portion by a groove, said second casing groove surface portion extending longitudinally as a step having a diameter smaller than the diameter of said flange; a third shell groove surface portion extending inward from the second shell groove surface portion along a plane or curve toward the casing center line, and then extending longitudinally in a cylindrical or curved shape; and a fourth casing groove surface portion extending outwardly from the third casing groove surface portion and away from the casing longitudinal centerline, wherein the fourth casing groove surface portion has a conical or curved shape. . The casing according to claim 1, wherein the third shell groove surface portion extends inwardly toward the casing center line along a curve and then extends curvedly in the longitudinal direction. The method of claim 1, wherein the third shell groove surface portion extends inward along a curve toward the casing center line and then extends curvedly in the longitudinal direction, and the fourth shell groove surface portion is relative to the longitudinal center line. A casing that curves outward. According to claim 1, wherein the shell groove third surface portion is cylindrical and extends longitudinally; The fourth shell groove surface portion extends conically outward with respect to the center line of the base. The casing according to claim 4, wherein the sleeve portion and the base portion are integrated with each other. The casing of claim 1, wherein the base and the sleeve are separate components connected to each other. 7. The device of claim 6, wherein the base has a central longitudinal passageway, and the sleeve includes a nipple disposed within the longitudinal passageway, wherein an end of the nipple is positioned in the passageway to secure the base and the sleeve to each other. Casing flared against inner shoulder. The method of claim 1, wherein a projectile disposed at the inlet, a quantity of gunpowder in the sleeve portion, and a primer cap in the bore of the base portion are combined, thereby forming a cartridge; Also in combination with the bolt of a firearm, having a hook; a proximal end of the flange contacts the bolt and the hook has a lip arranged to pull on a first surface of the flange when the bolt moves in a direction away from the bolt; The lip of the hook rests on the first surface of the step. A method of firing a projectile from a cartridge of a firearm, comprising:
(a) forming a cartridge including the casing of claim 1 and placing a primer in a recess of the proximal end of the base portion, placing a quantity of gunpowder within the sleeve portion, and placing a projectile within the inlet of the sleeve portion;
(b) pushing the cartridge into the chamber of a firearm by contacting the proximal end of the casing of the cartridge with the face of a bolt of the firearm, wherein the lip at the end of the movable hook portion of the bolt gasses the casing flange. (gasping) and the lip is in contact with a step of the base of the casing;
(c) expelling the projectile from the casing portion entrance by causing the gunpowder in the sleeve portion to deflagrate, via a firing pin in the bolt; and
(d) pulling the casing from the chamber of the firearm by the bolt and hook.
Including, launch method.