US20110174188A1

US20110174188A1 - Rifle and Handgun Cartridge

Info

Publication number: US20110174188A1
Application number: US12/691,314
Authority: US
Inventors: Reinhard Schuster
Original assignee: SCH PATENTE GmbH
Current assignee: SCH PATENTE GmbH
Priority date: 2010-01-21
Filing date: 2010-01-21
Publication date: 2011-07-21

Abstract

A rifle or handgun cartridge is formed to have an overall length of about 2.260 inches, or 57.4 millimeters. The shell case has a case length between 1.550 inches and 1.650 inches and a neck forming a mouth for a standard .224 caliber bullet. The shoulder adjoining the neck widens from the neck to a diameter of between 0.400 inches to 0.415 inches, and preferably 0.4059 inches. The adjoining shell body forms the main powder chamber for receiving an explosive charge. A head adjoins the shell body and forms a base of the shell case. The head has a primer pocket formed therein communicating with the main powder chamber through a vent hole formed between the primer pocket and the main powder chamber.

Description

BACKGROUND OF THE INVENTION

Field of the Invention

The invention lies in the field of interior ballistics and relates, more specifically, to a novel cartridge. Ballistics is generally divided into three distinct categories, namely, interior ballistics, exterior ballistics, and terminal ballistics. Here, we deal primarily with interior ballistics and we will briefly touch on the effect of the novel bullet on exterior ballistics.
A variety of parameters influence the ballistic behavior of powder-accelerated ammunition. In terms of the interior ballistics, the shape of the and dimensions of the cartridge shell (relative to the interior bore dimensions of the gun chamber), the amount and characteristics of the propellant (powder) charge, the primer and the primer vent connection to the main cartridge chamber are some of the primary aspects of interior ballistics behavior. Pressure and head space parameters are also important and they must be balanced against the other parameters.
This invention relates to rimmed cartridges and to rimless cartridges. Rimmed cartridges are provided with a base that has a wider diameter than the main body of the cartridge. The wider base forms a rim around the cartridge bottom with which the cartridge rests against the entry rim of the chamber. The base of rimless cartridges typically has the same or even smaller diameter than the body. The cartridge sits in and braces against the chamber walls to define its insertion depth. An extraction groove remains outside the chamber so as to allow the cartridge shell to be removed after the bullet has been fired.
In the following description the novel cartridge (the “.224 Schuster” or “.224 SCH”) will be compared primarily with the .223 Remington cartridge. The .223 Remington is used in a variety of rifles, notably in AR15-type rifles and in the M16 and A2 Type Carbine (Bushmaster). It is also used in some handguns, such as the Taurus Raging Bull. The .223 Remington is one of the most popular varmint hunting cartridges, and it is also a widely disseminated military rifle cartridge. In the context it is referred to as 5.56×45 mm NATO military round.
The .223 Remington can be loaded with a variety of bullet weights, typically ranging from 40 grain (e.g., Hornady) to 60 grain bullets, usually in Nosier tip bullets. The round also comes with heavier bullets, of up to 90 grain (e.g., Berger), but the lighter weights are typically considered better performers than the heavier weights. The primarily popular bullet weights are 55 grains for varmint hunting and 62-63 grains for the military round.
A similar cartridge has recently been introduced with the designation .224 AR. It is similar to the 6 mm AR in most respects, but it allows loading with .224 diameter bullets. The water capacity of the new .224 AR is slightly larger than that of the .223 Remington. The case length of the .224 AR is designed so that it can be loaded with relatively heavier bullets (e.g., 80-90 grain), yet still fits typical magazines. Due to the relative stubby cartridge body and its large cartridge diameter, the .224 AR is quite limiting in terms of magazine capacity.
Over the years new bullets with a better aerodynamic form have been created by several manufacturers and with higher weights of 75 to 80 Grains. The bullets have a longer overlap (from the case mouth to the overall length) at standard ammunition. Unfortunately, these bullets cannot be loaded at a standard magazine or action length.
Some manufacturers are offering loading data for these bullets with cartridge lengths that are over the industrial standards. These cartridges cannot be fired from magazines and each cartridge must be single feed to the action and does optional denote a special chamber dimension and barrel twist to result in good performance.
Reference is had, for instance, to the 75 grains Hornady A—Max and the Sierra Match King 80 Grains, described in:

- Hornady 7^thEdition—Handbook of Cartridge Reloading—Page 157 and 158
- Sierra 5^thEdition (V)—Rifle & Handgun Reloading Data—Page 213 to 232, especially Pages 213, 222 and 232.

I have found the available cartridges lacking in some respects and that the basic types of cartridge may still be further improved in terms of ballistic behavior, in terms of bullet weight variety, and in terms of easy integration in the most popular systems in existence.

BRIEF SUMMARY OF THE INVENTION

It is accordingly an object of the invention to provide a rifle and handgun cartridge, which overcomes the above-mentioned disadvantages of the heretofore-known devices of this general type and which provides for a new cartridge with a lower energy potential but with similar or even better features and ballistics for the preferred bullet weights within the range from 40 to 90 grain, and specifically in the heavier range of 70 to 90 grain.
With the foregoing and other objects in view there is provided, in accordance with the invention, a rifle and handgun cartridge, comprising:
a shell case having a case length between 1.550 inches and 1.650 inches and having a neck forming a mouth for a standard .224 inch diameter bullet;
a shoulder adjoining said neck and widening from said neck to a diameter of between 0.390 inches to 0.420 inches;
a shell body adjoining said shoulder and having an interior forming a main powder chamber for receiving an explosive charge;
a head adjoining said shell body and forming a base of said shell case, said head having a primer pocket formed therein communicating with said main powder chamber through a vent hole formed between said primer pocket and said main powder chamber.
The .224 SCH uses a new casing to include a longer bullet overlap at an approx. Cartridge length of a .223 Remington which has a standardized length of 2.260 inches.
Bullets with good aerodynamic features used herein are ovine Spitzer bullets in combination with a boat tail bullet form. This will reduce air residence and result in higher energy and bullet speeds and less bullet drop over longer shooting distances. Other types of bullets, of course, may be loaded with this cartridge, as desired.
I have found that a bullet weight from 75 to 80 grains provides for impressive performance in serious target competition and generally heavy weighted bullets are a good choice for shooting at longer distances. These heavy weighted bullets have better ballistics as a comparably light bullet at a higher speed level.
The novel cartridge .224 SCH can be loaded with any of these bullets. Other standard bullets may also be used.
It will be understood by those of skill in the art that the cartridge chamber of the rifle must be corresponded with the cartridge dimensions and the bullets. Most similar cartridges have a short bullet overlap and transition to the grooved barrel.
The shoulder angle to the mid axis influences barrel life and precision. A flat angle promotes burning powder fragments pushed into the barrel from burning powder charge. A higher angle of approximately 30 degrees to the mid-axis (i.e., 60° from shoulder to shoulder) supports burning of most powder fragments in the cartridge chamber. Much higher angles can cause misfire in repeating or self loading rifles.
In accordance with an added feature of the invention, the shoulder is formed by a conical wall that encloses an angle of between 25 and 45 degrees relative to a longitudinal axis of the cartridge, preferably between 28 and 35 degrees. The preferred shoulder to shoulder angle is 60° 04′29″.
In accordance with an additional feature of the invention, the shoulder walls merge towards an imaginary apex lying on the longitudinal axis of the cartridge and the imaginary apex lies within the neck, just short of the mouth.
In accordance with a preferred feature of the invention, the shell case has a case length of between 1.580 and 1.620 inches, and preferably 1.600 inches.
In accordance with a further feature of the invention, the shoulder widens to a widest diameter of 0.4059 inches, and the neck has a diameter of substantially 0.2575 inches or of substantially 0.276 inches.
The basic casings can be necked down to hold different standard or new bullet diameters result in different cartridges which can be loaded in one and the same magazine and in one headspace.
It should be understood, in sum, that the invention provides for a new cartridge that allows for a better variety of bullet weights to include better BC formed bullets up to approx. 80 grains that can be fired from standard magazine length of a .223 Remington action.
Rifles that are chambered for the .224 SCH cartridges can be easily used in different calibers by conversion uppers while using the same basic cartridge and magazine features.
In accordance with an added feature of the invention, the shoulder walls merge towards an imaginary apex lying on the longitudinal axis of the cartridge and the imaginary apex lies within the neck.
Bullets with good aerodynamic features are defined by a long ovigne Spitzer bullet design in combination with a boat tail bullet form. This will reduce air resistance and result in higher energy and bullet speeds and less bullet drop over longer shooting distances.
Bullet weights for shooting at longer distances or accuracy shooting are mostly above average bullet weights. Most in the upper half or third of the usable bullet weights are recommended for the caliber.
The cartridge chamber of the rifle must, of course, be formed to correspond with the cartridge dimensions and the bullets. Most similar cartridges have a short bullet overlap and transition to the grooved barrel.
The shoulder angle to the mid axis influences barrel life and shooting precision. A flat angle promotes burning powder fragments pushed into the barrel from burning powder charge. A higher angle of approximately 30 degrees to the mid-axis (double 60 degrees from shoulder to shoulder) supports burning of most powder fragments in the cartridge chamber. Much higher angles can cause misfire in repeating or self-loading rifles.
Although the cartridge starts at a reduced power level relative to the .223 Remington, it results in better data of speed energy and bullet drop at similar bullet weights. See Tables 1 to 3.
In sum, the novel .224 casing and cartridge has a better variety of bullet weights to include better ballistic coefficient formed bullets of up to about 80 grain, or more, which can be fired from magazines that are standardized to the .223 Remington action. The resulting rounds have improved ballistic behavior such as wind drift, bullet drop, and better speed and energy data. Also, a variety of calibers up to 8 mm S caliber (.323) by necked-down casings.
The novel cartridge can be easily integrated in existing systems and magazine lengths adopted for the .223 Remington. The novel cartridge uses the same major basic cartridge features for a variety of different calibers, from 0.220 inch to 0.323 inch at a high magazine capacity with the same basic magazine features.
As noted, the cartridge may be formed as a rimmed cartridge or as a rimless cartridge. The rimmed cartridge is provided for break up guns and combined guns. The remaining dimensions and data remain the same for the rimmed and rimless versions, except that slightly altered shoulder-powder room dimensions may be chosen. This applies, for instance, to lower pressure versions for break up guns.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a rifle and handgun cartridge, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of the specific embodiment when read in connection with the accompanying drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

FIG. 1 is a longitudinal sectional view taken through a schematic cartridge casing according to the prior art;

FIG. 2 is a diagrammatic side view of a rimless cartridge according to the invention shown in millimeter dimensions;

FIG. 3 shows the same cartridge in inch dimensions;

FIG. 4 illustrates an embodiment of a comparison cartridge in millimeter dimensions; and

FIG. 5 shows the same cartridge in inch dimensions.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is seen a longitudinal section through a cartridge provided in order to clarify the nomenclature used herein. The illustrated cartridge is a rimless cartridge. Starting from the top, a bullet would be seated in a mouth 1 and a neck 2 (sometimes referred to as a “throat”) would be crimped around the bullet in order to retain the same safely. The cartridge then widens via a shoulder 3, which connects the neck 2 to a body 4. Here, the body 4 is completely cylindrical, without a chamfer and therefore with a steady outer diameter from the shoulder/body transition to the bottom of the cartridge. As will be seen below, the novel cartridge (.224 Schuster and .243 Schuster) has a slight conicity as it widens from the shoulder down to the base.
The body 4 is adjoined by a head 5, which forms the base of the cartridge. The head 5 forms a belt 6 and a rim 7. Even though the figure illustrates a rimless cartridge, there is still provided a rim 7, which is formed due to an extraction groove 8 formed between the belt 6 and the rim 7. A primer pocket 9 is formed centrally in the base of the head 5. The primer pocket 9 connects via a vent 10 into a main chamber 12. In this case, there is illustrated only a single vent hole, but it is possible for two or more to be provided. The vent 10 is defined by a web, which forms the wall between the primer pocket 9 and the chamber 12.
Turning now to FIG. 2, there is shown an embodiment of the cartridge according to the invention. The cartridge is shown with a Spitzer bullet and an overall length of 57.43 mm, or 2.261″. This corresponds to the .223 Remington. The length of the cartridge shell is 1.600″ or 40.64 mm, which is considerably shorter than the .223 Remington (1.76″). The length of the neck is 0.2457″, or 6.24 mm, again shorter than the .223 Remington (0.203″).
The cartridge shell is also referred to as a shell case. The length of the shell case, measured from the mouth to the very bottom wall, according to the illustrated embodiments is 40.64 mm or 1.600″. The shell case length may be varied within a range of about 1.55″ to 1.65″ and formed for standard caliber bullets. The casing is suitable for a variety of calibers, including 8 mm S (0.323″) with necked-down casings.
The shoulder 3 of the novel cartridge is quite pronounced, as the shoulder walls enclose an angle of slightly more than 60 degrees. The corresponding angle of the .223 Remington hunting and military service cartridge is about 46 degrees. That is, the imaginary apex of the shoulder 3 of the novel cartridge comes to lie just inside the neck 2 or throat 2 of the cartridge shell, at a distance of 1.577″ or 40.055 mm from the base. The corresponding apex of the .223 Remington comes to lie well ahead of the mouth 1.
The bullet illustrated here is a Spitzer bullet which, with proper seating depth in the neck of the cartridge shell, results in an overall length of the cartridge of 57.43 mm or 2.261″. It will be understood that any of a plurality of other bullet shapes are available as well. The primer pocket 9 is sized so as to accept and properly seat a “small rifle” primer.
The following tables compare the novel cartridge with the .223 Remington cartridge loaded with comparable bullet weights. The rounds were loaded so as to result in a muzzle speed for the novel cartridge of 2,882 feet per second (fps) and 3083 fps for the .223 Remington cartridge. The novel cartridge was loaded with an 80 grain Spitzer hollow point boat tail bullet. The Sierra match King (Sierra No. 9390) was used for the comparisons. The .223 REM cartridge was loaded with a 62 grain Spitzer full metal jacket boat tail bullet.
The two cartridges are loaded so as to have the following pressure levels: 4300 bar for the .223 REM and 4050 bar for the .224 SCH. Widely used pressures lie in the range from approx. 3800 to approx. 4300 bar. The comparison, therefore, is effected at the mid-range of 4050 for the novel cartridge. The pressure difference between 3800 and 4300 does not result in a large difference in the bullet speed and energy.
The bullet speeds are calculated with “QuickLOAD Ballistic Program.” The speed data are an average formed from the 10 first listed loads from this calculation with different powders. The cartridges are loaded to approximately 85% of maximal pressure level.
The data in the tables are given in steps of 25 yards from zero to 1,000 yard distance. The data are calculated with SIERRA “Infinity Exterior Ballistics Software.”
Tables 1A and 1B show wind drift at 5 and 10 miles per hour light crosswind, respectively. Higher wind drift is proportional to this data. The novel cartridge features result in a lower wind drift. The novel cartridge is identified as “.224 SCH” while the reference cartridge is identified as “.223 REM”

TABLE 1A

Range	Wind Drift (Inches) - 5 mph

(Yards)	.224 SCH	.223 REM

25	0.02	0.03
50	0.09	0.11
75	0.21	0.26
100	0.37	0.47
125	0.59	0.74
150	0.85	1.07
175	1.17	1.48
200	1.54	1.96
225	1.97	2.51
250	2.46	3.14
275	3.0	3.85
300	3.61	4.64
325	4.28	5.53
350	5.02	6.5
375	5.83	7.57
400	6.71	8.74
425	7.67	10.01
450	8.71	11.4
475	9.83	12.9
500	11.03	14.52
525	12.32	16.26
550	13.7	18.13
575	15.17	20.14
600	16.75	22.28
625	18.42	24.57
650	20.19	27.0
675	22.07	29.58
700	24.06	32.32
725	26.17	35.21
750	28.39	38.26
775	30.72	41.47
800	33.18	44.83
825	35.76	48.35
850	38.46	52.01
875	41.28	55.82
900	44.23	59.75
925	47.3	63.82
950	50.49	68.01
975	53.81	72.31
1000	57.24	76.73

TABLE 1B

Range	Wind Drift (Inches) - 10 mph

(Yards)	.224 SCH	.223 REM

25	0.05	0.06
50	0.18	0.23
75	0.41	0.52
100	0.74	0.93
125	1.17	1.47
150	1.7	2.15
175	2.34	2.96
200	3.08	3.91
225	3.94	5.01
250	4.92	6.27
275	6.01	7.69
300	7.23	9.28
325	8.57	11.05
350	10.04	13.0
375	11.66	15.14
400	13.43	17.48
425	15.35	20.04
450	17.42	22.81
475	19.66	25.81
500	22.06	29.04
525	24.64	32.53
550	27.4	36.27
575	30.35	40.28
600	33.49	44.56
625	36.83	49.13
650	40.38	54.0
675	44.15	59.17
700	48.13	64.64
725	52.34	70.43
750	56.77	76.53
775	61.45	82.94
800	66.36	89.67
825	71.51	96.7
850	76.91	104.02
875	82.56	111.63
900	88.46	119.51
925	94.6	127.64
950	100.99	136.02
975	107.62	144.62
1000	114.48	153.46

Table 2 shows the bullet drop. Although the novel cartridge starts at a lower speed and energy level, the trajectory of the cartridge is flatter for long range shooting. The bullet drop is better above approximately 600 yards distance. In the shorter range, the bullet drop is comparable between the novel round and the reference round.

	TABLE 2

	Bullet Drop (Inches)

	.224 SCH	.223 REM
Range	80 grs BTHP	62 grs BTHP
(Yards)	at 2882 fps	at 3083 fps

25	−0.13	−0.12
50	−0.54	−0.47
75	−1.22	−1.08
100	−2.21	1.96
125	−3.49	−3.12
150	−5.1	−4.58
175	−7.04	−6.35
200	−9.33	−8.46
225	−11.97	−10.92
250	−15.0	−13.75
275	−18.41	−16.97
300	−22.24	−20.61
325	−26.49	−24.69
350	−31.2	−29.24
375	−36.37	−34.3
400	−42.02	−39.88
425	−48.2	−46.02
450	−54.91	−52.77
475	−62.19	−60.16
500	−70.06	−68.23
525	−78.56	−77.02
550	−87.71	−86.6
575	−97.54	−97.0
600	−108.11	−108.29
625	−119.43	−120.29
650	−131.56	−133.77
675	−144.54	−148.09
700	−158.4	−163.56
725	−173.21	−180.26
750	−189.0	−198.25
775	−205.83	−217.64
800	−223.75	−238.49
825	−242.83	−260.89
850	−263.12	−284.94
875	−284.68	−310.7
900	−307.58	−338.26
925	−331.88	−367.71
950	−357.64	−399.11
975	−384.94	−432.55
1000	−413.84	−468.1

Table 3 shows the bullet speed and energy. Although the novel cartridge starts at a lower speed and energy level, the speed and energy are superior above 250 yard distance. Very little difference is found in the shorter distance range.

TABLE 3

	.224 SCH	.223 REM

80 grs. HPBT

62 grs. HPBT

Velocity	Energy	Range	Velocity	Energy
(ft/sec)	(ft/lbs)	(Yards)	(ft/sec)	(ft/lbs)

2882.0	1475.2	0	3083.0	1308.3
2826.0	1418.4	25	3003.7	1241.9
2770.7	1363.5	50	2925.9	1178.4
2716.1	1310.3	75	2849.5	1117.6
2662.2	1258.8	100	2774.3	1059.4
2609.0	1208.9	125	2700.5	1003.8
2556.4	1160.7	150	2627.9	950.5
2504.4	1113.9	175	2556.4	899.5
2452.9	1068.6	200	2486.1	850.7
2402.0	1024.7	225	2416.8	804.0
2351.8	982.3	250	2348.6	759.2
2302.1	941.3	275	2281.5	716.5
2253.0	901.6	300	2215.5	675.6
2204.5	863.2	325	2150.5	636.6
2154.5	824.4	350	2086.6	599.3
2104.8	786.9	375	2023.8	563.8
2055.8	750.7	400	1962.2	530.0
2007.5	715.8	425	1901.7	497.8
1959.9	682.2	450	1842.5	467.3
1913.0	649.9	475	1784.5	438.3
1866.7	618.9	500	1727.8	410.9
1821.3	589.1	525	1672.5	385.0
1776.2	560.3	550	1618.8	360.7
1731.5	532.5	575	1566.5	337.8
1687.7	505.9	600	1515.9	316.3
1644.8	480.5	625	1467.1	296.3
1602.9	456.3	650	1420.1	277.6
1562.0	433.3	675	1375.0	260.2
1522.0	411.4	700	1331.9	244.2
1483.2	390.7	725	1291.1	229.4
1445.4	371.1	750	1252.6	216.0
1408.9	352.5	775	1216.6	203.7
1373.5	335.1	800	1183.1	192.7
1339.5	318.7	825	1152.2	182.7
1306.8	303.3	850	1123.9	173.9
1275.5	288.9	875	1098.1	166.0
1245.7	275.6	900	1074.8	159.0
1217.4	263.2	925	1053.5	152.8
1190.7	251.8	950	1033.9	147.1
1165.7	241.3	975	1015.8	142.0
1142.3	231.7	1000	998.9	137.4

The term “substantially” as used in the claims is to be understood with reference to the respectively modified measurement or numerical value. The term varies and allows a modification of the associated value by a maximum of 3 to 6%. Where the modifier is not used in the context, the allowed variation is within the acceptable error range as understood by those of skill in the art and will, typically, lie in the 1-2% range.

Claims

1. A rifle or handgun cartridge, comprising:

a shell case having a case length between 1.550 inches and 1.650 inches and having a neck forming a mouth for a standard .224 inch diameter bullet;

a shoulder adjoining said neck and widening from said neck to a diameter of between 0.390 inches to 0.420 inches;

a shell body adjoining said shoulder and having an interior forming a main powder chamber for receiving an explosive charge;

a head adjoining said shell body and forming a base of said shell case, said head having a primer pocket formed therein communicating with said main powder chamber through a vent hole formed between said primer pocket and said main powder chamber.

2. The cartridge according to claim 1, wherein said shoulder is formed by a conical wall enclosing an angle of 25 to 45 degrees relative to a longitudinal axis of the cartridge.

3. The cartridge according to claim 2, wherein said conical wall encloses an angle of approx. 28 to 35 degrees with the longitudinal axis of the cartridge.

4. The cartridge according to claim 1, wherein said shoulder walls enclose an angle of substantially 60° with one another.

5. The cartridge according to claim 4, wherein said shoulder walls merge towards an imaginary apex lying on the longitudinal axis of the cartridge and the imaginary apex lies within said neck.

6. The cartridge according to claim 1, wherein said shell case has a case length of between 1.580 and 1.620 inches.

7. The cartridge according to claim 6, wherein said shell case has a case length of 1.600 inches.

8. The cartridge according to claim 1, wherein said shoulder widens to a widest diameter of 0.4059 inches.

9. The cartridge according to claim 1, wherein said neck has a diameter of substantially 0.2575 inches.

10. The cartridge according to claim 1, wherein said neck has a diameter of substantially 0.276 inches.