|Publication number||US3815503 A|
|Publication date||Jun 11, 1974|
|Filing date||Oct 18, 1971|
|Priority date||Oct 19, 1970|
|Also published as||CA958945A, CA958945A1, DE2151607A1|
|Publication number||US 3815503 A, US 3815503A, US-A-3815503, US3815503 A, US3815503A|
|Original Assignee||Digid Ministry Of Defense, Direccion General De Investiga|
|Export Citation||BiBTeX, EndNote, RefMan|
|Patent Citations (7), Referenced by (20), Classifications (4)|
|External Links: USPTO, USPTO Assignment, Espacenet|
United States Patent 1191 Iniantino June 11, 1974  SELF-PROPELLING BALLlSTlC  References Cited PROJECTILES UNITED STATES PATENTS  Inventor: Osvaldo Cesar Iniantino, Buenos 750,623 1/1904 Edmundsm 102/497 Aires, Argentina 1,191,357 7/1916 Snyder lO2/49.7 1,446,711 2/1923 Ludorf 102/497 Asslgneei Dll'mwn General de lljvfrstlgaclon y 1,468,822 9/1923 Ludorf 102/497 Desarrollo (DIGID) Ministry of 1,481,872 1/1924 Miller 102/497 Defense of the Argentine Republic, 2,424,934 7/1947 Kasper 102/497 Buenos Aires, Argentina 3,398,684 8/1968 Kuavle 102/497 X  Filed: 1971 Primary Examiner-Samuel Feinberg  Appl. No.: 189,905 Assistant Examiner-H. J. Tudor Attorney, Agent, or FirmLerner, David, Littenberg 30 Foreign Application Priority Data Samuel Oct. 19, 1970 Argentina 231877 57 ABSTRACT Ballistic projectiles for firearms and more particularly 'ga g g to a self-propelling ballistic projectile which, upon 11:. l 58] Fieid 7 DIG 1 ing, is totally expelled from the firearm without leaving a residual case therein.
4 Claims, 6 Drawing Figures SELF-PROPELLING BALLISTIC PROJECTILES Conventional fireami cartridges comprise a case, a projectile or bullet fitted at the mouth end of the case, a propellant charge inside the case, and priming means at the rear end of the case. These cartridges are loaded into the chamber of a firearm and, upon being fired, the propellant charge impells the projectile or bullet through the barrel of the firearm. The case is retained in the chamber and elaborate means have been devised to eject it either manually or automatically.
Theseejecting means are prone to malfunction and are a major cause of jamming. Besides, the necessity of ejecting the residual case reduces the frequency of firing and severely limits the efiectiveness of the firearm.
In addition, conventional cartridges comprise several independent parts requiring an elaborated manufacturing process which makes them rather expensive.
It is also evident that the bullet proper is only a fraction of the total weight of the cartridge and therefore, storage volume and transportation costs are disproportioned to the effectiveness of the ammunition.
Efforts to improve firearm ammunition in the recent past were directed towards reducing barrel erosion and attaining improved ballistic performance.
Modern firearms have barrel bores with a series of equidistant parallel groves (called rifling) which spiral from one end of the barrel to the other. These groves or rifling define land portions which bite into the surface of the bullet while it travels through the bore and causes it to spin. The gyroscopic effect thus created helps to stabilize the path of the bullet and increases the accuracy of fire.
The outer diameter of the bullet is, of necessity, slightly larger than the inner diameter across the lands of the bore and, as a consequence, the bore is subjected to sever erosion.
In view of the above-mentioned problems, several attempts have been made to produce a self-propelling ballistic projectile which is totally expelled through the barrel of the firearm from which it is fired. These attempts have not been successful mainly because the self-propelling projectiles were designed on the same criteria used for conventional ammunition, namely, the body of the projectiles had a diameter larger than the inner diameter across the lands of the barrel bore so that the lands of the bore bit into the surface of the projectile and imparted to it the above-referred to spinning motion.
This oversizing of the projectile body and the expansion it experienced under the pressure of firing, subjected the bore to severe erosion, decreased appreciably the kinetic energy of the projectile, and caused excessive gas leakage through the firearm chamber.
Other attempts to solve the above problem were centered about the design of a self-destroying case, but this created other problems which rendered this solution totally ineffective.
With a view to solving the problems normally associated with conventional ammunition andknown selfpropelling projectiles, the present invention provides a ballistic, self-propelling projectile adapted to be fired from a firearm having a helically grooved bore and capable of being totally expelled through said bore without leaving any residue in the firearm, said projectile comprising a body of substantially cylindro-ogival shape, having a propellant cavity therein, priming means in said propellant cavity, and an outer, peripheral flange at the rear,"terminal end of said body and integral therewith; the maximum outer diameter of said body being equal to, or slightly less than the diameter of said bore across the lands defined between said grooves; and the outer diameter of said rear peripheral flange being larger than the diameter of the bore across said lands; whereby, upon the projectile being fired and impelled through the bore, said rear peripheral flange is bit and deformed by the lands in the bore, and the projectile body expands under the pressure of firing and engages the lands in the bore thus causing the projectile to spin while it travels through the bore.
The basic principle of the invention resides in making the maximum outer diameter of the projectile body, equal or slightly less than the diameter of the bore of the firearm from which the projectile is to be fired. The desired spinning motion is produced, on the one hand, by a rear peripheral flange which, upon firing of the projectile, engages and is deformed by the rifling in the bore, and on the other hand, by engagement of the surface of the projectile with the rifling in the bore clue to the expansion caused by the ignition of the propellant charge.
This principle may be applied to ammunition of a wide range of calibres and intended for diverse types of firearms, such as portable, automatic, semi-automatic, or artillery weapons.
The main advantages of the invention are the elimination of the residual case and the reduction of barrel erosion. Other advantages are:
l. Supersonic munle velocity with the consequent increase in impact energy.
2. Higher offensive power since the full projectile structure strikes the target.
3. Less firearm recoil.
4. Lower manufacturing costs.
5. Possibility of simplifying the firearms using amm unition in accordance with the invention by eliminating the case ejecting mechanism and this eliminates a major source of mechanical trouble.
6. Possibility of increasing the frequency of firing by decreasing the firing cycle.
7. Lower weight, storage volume and transportation costs.
8. Better resistance to water and humidity.
The invention will now be described with reference to the accompanying drawings which illustrate, by way of example, a preferred embodiment of the invention.
In the drawings:
FIG. 1 is an elevation view, partially in section, of a ballistic projectile according to the invention.
FIG. 2 shows schematically the projectile of the invention in the chamber of a firearm, prior to firing.
FIG. 3 is a cross section along line III-III of FIG. 2.
FIG. 4 is a view similar to that of FIG. 2 but immediately after the projectile has been fired.
FIG. 5 is a cross section along line V-V of FIG. 4.
FIG. 6 is a perspective view of the projectile immediately after being fired showing the deformation of the rear peripheral flange.
With reference now to the drawings, the selfpropelling ballistic projectile shown in FIG. 1 comprises a single-piece body 1, preferably of cylindroogival shape, having an internal ogival or cylindroogival propellant cavity 2. The propellant cavity is closed at the rear end of the body by priming means 3 which could be of the central fire or ring fire type.
4 It should be noted that the rear flange 6 acts as a stop for the projectile in the chamber before the projectile is fired, and also as a guiding ring while the projectile travels through the bore. lt furthermore assists in stabi- The priming means 3 rest on an internal shoulder 4 5 lizing the projectile after it is expelled from the barrel. provided in the wall of the projectile body. I FIG. 5 is a cross section through line V-V of FIG. The propellant cavity contains a propellant charge 5 4 showing schematically the deformation or extrusion which may consist of common gun powder. suffered by the projectile while traversing the bore. The The projectile body 1 has, at its rear terminal end, an reference numeral 12 indicates the clearance between outer peripheral flange 6 formed integrally with the the bore and the projectile. projectile body and extending substantially at right an- The remnants of the primer 3 are expelled. together gles with respect to the longitudinal axis of the projecwith the projectile through the barrel. To accomplish tile. The outer diameter of the flange 6 is larger than this, several primer designs are possible and it is not the outer diameter of the cylindrical portion of the proconsidered necessary to discuss them in detail. It will be jectile body. The diameter and thickness of the flange l5 apparent to those expert in the art, that the priming 6 depend on the calibre of the projectile. means may be located at either end of the propellant In FIG. 2 the projectile is shown in the chamber C of cavity. a firearm prior to firing. The firearm barrel 7 has a se- The projectile body is preferably made of a brass ries of parallel grooves 8 which spiral from the chamber alloy although other suitable metals could also be emend to the muzzle end of the barrel and define land porplayed. I tions 9 therebetween. The performance of the self-propelling projectile of In the position shown in FIG. 2 the rear flange of the the invention was compared with conventional ammuprojectile abutts against shoulder means 10 provided in n n Qt: the same and different calibre. n h the chamber which hold it in place. As it may be best The -P P prolectlle tested had the followseen in FIG. 3, the outer diameter of the projectile g Characteflstlcsi body is equal or, preferably, slightly less than the inner diameter, across the lands, of the bore. Calibre 9 mm As an example, a desirable clearance between a calied) 5 1; bre 9 pro ectile and the bore of the correspondmg fire- Propellant charge 330 mg arm is in the order of 0.006 mm.
FIG. 4 shows the projectile immediately after it has The results of the tests are indicated in the attached tabeen fired by percussion of the priming means 3 with ble. the percussion pin (not shown) of the firearm. As it can The tests showed that the muzzle velocity of the probest be seen in FIG. 6, the rear flange 6 of the projectile jectile of the invention was frankly supersonic and subis deformed by the rifling and screws into the helical stantially higher than that of all the ammunition comgrooves of the bore. This produces the spinning of the pared. The recoil energy of the projectile of the invenprojectile. Almost simultaneously, the projectile body tion was also substantially less than that of ammunition expands slightly under the pressure of firing and enof the same calibre. gages the lands in the bore, which maintain and guide Ballistic tests conducted in a subsonic tunnel showed the spinning motion of the projectile until it abandons that the projectile of the invention had excellent ballisthe barrel through the muzzle. In FIG. 6 it has been intic stability, i.e., its centre of gravity followed a fixed dicated the indentations 11 formed by the rifling on the path after the projectile left the barrel and the propelsurface of the projectile body. lant charge became inert.
TABLE Test No. 279 280 281 282 283 on c.32 (3.32 c.9 C.9 Ammunition type long long long PAM according and Calibre to DGFM DGFM ORBEA (TM) DGFM int/99M Initial Velocity jmlsec.) 348 270 31 1 327 455 Initial Energy (Kgm) 15 23 31 44 59 Recoil Energy K .m 0.260 0.308 0.500 0.430 Dynamometer travel in) 0.241 0.284 0.460 0.372
Projectile Weight Ling) 2600 6300 6300 8100 6010 Common Propellant Charge Standard Standard Standard Standard hunting gun powder FANAZUL (T Winchester Specially Same PAM Same made Remarks barrel barrel as barrel 9- as 0.53 m 0.18 in before standard before DGFMi Direccion General de Fahricuciones Militares The stability conditions of the projectile of the invention were verified also with the Kranz equations.
An additional feature of the invention resides in the design of the propellant cavity 2. The ogival or cylindro-ogival shape of the cavity permits a better utiliza tion of of the explosive energy developed in the projectile, and the use of a smaller propellant charge than would be required in conventional ammunition equivalent calibre.
While the invention has been described in connection with a specific embodiment thereof, it is to be understood that this is by way of illustration and not by way of limitation, and the scope of the appended claims should be construed as broadly as the prior art will permit.
What is claimed is:
l. A ballistic, self-propelling projectile adapted to be fired from a firearm having a helically grooved bore and capable of being totally expelled through said bore without leaving any residue in the firearm, said projectile comprising an expandable body of substantially cylindro-ogival shape, the maximum outer diameter of said body being equal to or slightly less than the diameter of said bore across the lands defined between said grooves, which body expands under pressure of firing and engages the lands of said bore, said body havinga propellant cavity therein, said propellant cavity being substantially ogival; priming means in said propellant cavity; and an outer, peripheral flange at the rear, terminal end of said body and integral therewith, the outer diameter of said rear peripheral flange being larger than the diameter of the bore across said lands, and serving as a stop for the projectile in the firearm chamber before firing, whereby, upon the projectile being fired and impelled through the bore, said rear peripheral flange is bit and deformed by the lands in the bore which in conjunction with expansion and engagement of the projectile body with the lands in the bore causes the projectile to spin while it travels through the bore. ""ETTii ballistic, self-propelling projectile in accordance with claim 1 wherein said outer peripheral flange has a rectangular cross section.
3. The ballistic self-propelling projectile in accordance with claim 1 wherein said expandable body is made of a brass alloy.
4. The ballistic, self-propelling projectile in accordance with claim 1 wherein said propellant cavity is of
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