US 3154016 A
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Description (OCR text may contain errors)
Oct. 27, 1964 A. w. FREY 3,154,016
BALLISTIC PROJECTILE Filed Jan. 12. 1961 2 Sheets-Sheet 1 INVENTOR Albert W. Fr ey ATTORNEYS Oct. 27, 1964 Filed Jan. 12, 1961 A. W. FREY BALLISTIC PROJECTILE 2 Sheets-Sheet 2 INVENTOR Alb err 14'. Frey ATTORNEYS United States Patent 3,154,016 BALLISTIQ PROJECTHE Albert W. Frey, 1% S. 32nd St, (Iorsieana, Tex. Filed fan. 12, 1961, Ser. No. 82,245 4 Claims. (Cl. 10.2-92.5)
This invention relates to new and useful improvements in ballistic projectiles.
The invention is particularly directed to ballistic projectiles having circumferential grooves providing a unique peripheral flange arrangement which gives rise to new and unexpected ballistic performance of the projectiles.
In the past, it has been conventional to form projectiles of soft metals or materials, of hard metals jacketed in somewhat softer metals, or of hard metals provided with rotating bands, again formed of softer metals. It has also been known to form projectiles with a core of soft metal and a thin deformable jacket of a harder metal. In each instance, the ballistic performance of such projectiles has fallen short of what might be desired, in most cases due to the control of the projectile in its passage through the gun barrel by the lands of the barrel rifling rather than the bottoms of the grooves thereof, by excessive blow-by" and the concomitant erosion, or by excessive frictional resistance to passage of the projectile through the gun barrel. This invention seeks to overcome these disadvantages along with numerous more or less related or resultant features thereof.
It is a primary object of the invention to provide an improved projectile which may be formed of relatively hard metal such as brass, bronze, mild steel and the like without requiring a jacket of softer metal or rotating bands of such metal, the hard metals for example having hardnesses of B7O to B85 Rockwell.
A further object of the invention is to provide an improved projectile having reduced surficial contact with the gun barrel through which it passes, or reduced surficial loading so that less friction and heat is generated.
Another object of the invention is to provide an improved projectile having circumferential flanges wherein the forward flanges offer reduced frictional contact and resistance, and the rearward flanges provide very effective gas sealing but result in reduced frictional resistance.
A further object of the invention is to provide an improved projectile formed with circumferential flanges of the groove diameter of the gun barrel through which the projectile is fired whereby the flanges do not undergo flexing or distortion, but only a small portion thereof undergoes a shearing action by engagement with the rifling lands of the gun barrel; and in which the rifling lands cut or shear into the flanges rather than displacing metal laterally or longitudinally, all of the metal being moved radially inwardly to preserve the balance of the projectile.
A still further object of the invention is to provide an improved projectile which, in its passage through a gun barrel, is guided by the groove bottoms of the barrel rifling rather than the lands thereof.
Yet another object of the invention is to provide an improved projectile which, upon firing through a gun barrel, leaves the barrel with its rotational balance, or its rotational kinetic energy balance intact.
An additional object of the invention is to provide an improved projectile having peripheral flanges with angular faces, the angles of which may be varied to obtain the desired yielding point at selected locations on the flanges so that the projectile may be adapted for fabrication with various types of relatively hard metals.
A still further object of the invention is to provide an improved projectile which is readily employable as a solid projectile or as a shell of the artillery variety.
A further object of the invention is to provide an im- EJS igfllfl Patented Oct. 2'7, 1964 "Ice proved projectile having peripheral flanges in which the gas pressure generated by the burning propellant is equalized across each flange until it engages the groove bottoms of the gun barrel rifling so that no flexing of the flanges occurs, and in which, after the flange has engaged the groove bottoms, the flange faces remain flat against said groove bottoms so that there is no flexing to cause angular engagement and shifting of the flange faces from engagement with the groove bottoms over substantially the entire surface area of said faces.
A further .object of the invention is to provide an improved projectile in which the gas pressure generated by the burning propellant is distributed evenly over the area of any one of the flanges of the projectile, but in which the larger area of the flanges engaging the groove bottoms of the barrel rifling causes the grooves to control the projectile so that the projectile is centered in the barrel and does not yaw in the barrel or in its travel after leaving the barrel, this being true because the portions of the flanges engaging the rifling lands is less than the area engaging the bottoms of the grooves and the latter become controlling.
Yet another object of the invention is to provide an improved projectile having peripheral flanges in which the flanges have angular side walls which provide longitudinal support of the flanges under the gas pressure generated by the burning propellant.
Another object of the invention is to provide an improved projectile providing a better seal with the bore of a gun barrel for reduced blow-by and reduced erosion, and on which very thin anti-friction coatings of softer metals may be employed.
As used herein, lands are the upstanding helical ridges normally present in a gun barrel, and land diameter and bore diameter interchangeably designate the diameter between the surfaces of diametrically opposed lands. Groove bottom is the bottom of the grooves between adjacent lands, and groove diameter is the diameter between the bottoms of diametrically opposed grooves.
A construction designed to carry out the invention will be hereinafter described, together with other features of the invention.
The invention will be more readily understood from a reading of the following specification and by reference to the accompanying drawings, wherein examples of the invention are shown, and wherein:
FIG. 1 is a side view in elevation of a projectile constructed in accordance with this invention,
FIG. 2 is a rear elevational view of the projectile,
FIG. 3 is an enlarged, fragmentary view, partly in elevation and partly in section of the rearward portion of the projectile,
FIG. 4 is a view similar to FIG. 3 and showing the projectile in an initial stage of fabrication,
FIG. 5 is a vertical, cross-sectional view taken upon the line 5-5 of FIG. 3,
FIG. 6 is an enlarged fragmentary view in elevation of the rearward portion of the projectile after the same has.
passed through a gun barrel,
FIG. 7 is a rear elevational view taken at right angles to FIG. 6,
FIG. 8 is a lateral View, partly in elevation and partly in section of a modified form of the projectile, and
FIG. 9 is a rear elevational view of the form of the invention shown in FIG. 8.
In the drawings, the numeral 10 designates a projectile constructed in accordance with this invention and which may be of any suitable type or caliber. For the purposes of illustration and convenience, the invention has been primarily illustrated and will be primarily described with respect to its application to a .30 caliber projectile of thev boattail variety for a .3006 cartridge, but it is to be understood that the invention may be equally well applied to projectiles of both the solid and shell or artillery types since the invention is to be found primarily in the external configuration of the projectile.
The projectile as shown in FIG. 1 is formed with the usual nose or forward section 11 and the rearward, tapered or semi-boattail portion 12. As shown in FIG. 4, the body portion 13 of the projectile is initially formed with a plurality of spaced, angular grooves 14 each of which includes a bottom or forwardly facing wall 15 disposed at some acute angle, such as 30, with respect to the axis of the projectile and a for-Ward, rearwardly facing wall 16 disposed at a greater angle with respect to the axis of the projectile, such as 60, but at an angle less than 90 with respect either to the axis of the projectile or the bottom walls 15. The walls 15 and 16 of each of the grooves intersect at an acute angle, less than 90, and such angle may be greater or lesser acute depending upon the material from which the projectile is formed and the performance characteristics desired thereof. The bottom wall 15 of each of the grooves also intersects the forward wall of the next rearward groove at an acute angle, which again, may vary to some extent, so as to form a plurality of spaced flanges 17 extending peripherally or circumferentially of the projectile in parallel relationship and terminating at their outer ends in apexes 18 of more or less circular knife edge configuration.
Assuming that this projectile is to be fired through a rifled gun barrel of nominal .30 caliber in which the bore diameter or land diameter is 0.300 inch and the groove diameter is 0.308 inch, with usual tolerances, the nose portion 11 of the projectile at its point of maximum diameter will be 0.300 inch or less in diameter, and the tail section 12 will normally be of no greater, and desirably of less diameter. In this instance, the apexes 18 of the flanges 17 may desirably have a diameter of 0.312 plus or minus 0.002 inch, and the grooves 14 have a depth of 0.0325 inch, resulting in a spacing of of an inch between adjacent ones of the apexes 18. This is assuming a 30 angle between the axis of the projectile and the forward walls 15, and a 30 angle between the rearward walls 16 and the forward walls 15. The rearmost groove 14 will of course merg into the rearward or tail section 12, while a small angular flange 19 will be formed between the forward wall of the forwardmost groove and the periphery of the nose portion 11. The forward side of the flange 19 will, however, be disposed at the same angle with respect to the projectile axis as the forward walls 15.
The projectile may be formed of brass, bronze, mild carbon steel, or other suitable and relatively hard metals which normally may not be employed as a projectile in the absence of soft metal jackets or rotating rings, and may be brought to the first stage illustrated in FIG. 4 by machining, casting, molding, or any other suitable or desirable method of fabrication. Machining has been found most suitable both for ease and speed of manufacture as well as the obtaining of uniformity in the finished product. Further, materials normally employed for machining purposes are of more uniform composition and physical and chemical properties throughout their mass and hence are to be desired.
Following the initial forming operation illustrated in FIG. 4 the apexes 18 of the flanges 17 are then bent or deformed rearwardly and inwardly toward the axis of the projectile by passing the projectile through a suitable rolling operation, a suitable die, or by any other suitable or desirable mechanical means to form narrow annular surfaces 20 on the outer extremities of the flanges, the surfaces 20 being circumferential and cylindrical with respect to the axis of the projectile. Within manufacturing tolerances, the surfaces should have a diameter equal to the groove diameter of the gun barrel which, in the case of a. .30 caliber projectile and gun barrel would be of the magnitude of 0.308 inch. This second forming operation necessarily results in the formation of angular lips 21 immediately adjoining the rearward margin of each of the surfaces 20, the faces of the lips 21 extending at an obtuse angle with respect to the rearward faces 16 of the grooves 14 and being very nearly parallel, in cross-section, to the forward faces 15. It is the annular surfaces 20 which engage the bottoms of the rifiing grooves of the gun barrel, and as will be seen, without undergoing deflection or distortion, these surfaces function to control the path of travel of the pr jectile through the gun barrel and to center the projectile most accurately therein.
The performance of the projectile as it is fired through a gun barrel is illustrated in FIGS. 6 and 7. As the projectile moves forwardly and each successive one of the flanges approaches the rearward ends of the barrel rifiing lands the gas pres-sure resultant from the combustion of the propellant charg will be equalized on both sides of each of the flanges 17, and there will be no tendency for this gas pressure to cause the flanges to flex forwardly during the time prior to the moment the flanges enter the actual bore of the gun. As each of the flanges engages the rearward ends of the rifiing lands, the lands will cut into or shear into the flanges at spaced points, moving a small portion of the metal from which the project't e is formed inwardly and possibly rearwardly, but otherwise cutting a plurality of shallow, sharp cornered grooves 22 at spaced points in the circumference of each of the annular faces 20. The portions 23 of the faces 20 between adjacent ones of the grooves 22 will be brought immediately into snug sliding engagement with the groove bottoms of the barrel rifiing, and since the diameter of the projectile between diametrically-opposed ones of the face portions 23 is equal to the groove diameter of the barrel, there will be no rearward flexing of the flanges due to the forcing of the projectile into the barrel, or forward flexing of the flanges due to the application of gas pressure thereto. Instead, the portions 23 will lie in snug, flat, face-to-face engagement with the groove bottoms and will not be forced into a position where the portions 23 are at an angle with respect to said groove bottoms. There is no lateral shifting of metal in the flanges, and hence, the rotational balance of the projectile is retained. At the same time, the area of the land faces of the rifiing normally being somewhat less than the area of the groove bottoms, the latter will control the path of movement of the projectile since much less force is required to offset the notches 22 inwardly than would be required to offset one of the sections 23. Even if the sections 22 equaled the sections 23 in area, the latter being at a greater diameter would still constitute a larger surficial area and would remain in control of the projectiles movement.
In actuality, the forward ones of the flanges act primarily as guides, and while undergoing no flexing, offer reduced frictional resistance to the passage of the projectile through the gun barrel since less surficial area of the projectile is in contact with the wall of the gun barrel. The rearward group of flanges also function to guide the projectile, but also provide the necessary gas seal to prevent blow-by, with its resultant erosion of the projectile and/or the gun barrel, and yet carry out this function with reduced friction and with no perceptible flexing of the flanges due to their close fit in the groove diameter of the gun barrel.
It is this arrangement which makes possible the forming of the projectile of relatively hard material without requiring a softer metal jacket, softer metal rotating bands, or the like. The latter tend to distort and to shift laterally as the projectile is forced into the rifiing of the gun barrel, thereby causing a loss of the rotational balance of the projectile and placing the control of the projectile movement in the lands of the rifiing rather than the bottoms of the grooves thereof. Since the sections 23 of the flanges do not undergo flexion either inwardly or outwardly, there can be no damage to the groove bottoms even though the projectile is formed of relatively hard material, and the small area of the grooves 22 are not suflicient to result in such damage. The reduced surficial contact results in less friction and therefore less heat generated by the passage of the projectile through the gun barrel, and also results in less wear of the bore of the gun barrel.
The rifling lands cut or shear into the flanges rather than displacing metal laterally or circumferentially, but other than imparting rotation to the projectile, the lands do not control the path of travel of the projectile. The projectile is guided by the groove bottoms so that it is accurately centered in the gun barrel in its passage therethrough and leaves the barrel with its rotational balance or rotational kinetic energy balance intact. The sections 23 of the flange faces 20 are held flat against the groove bottoms without flexing to cause angular displacement and angular and imperfect engagement, and at the same time, the gas pressure generated by the propellant charge is distributed evenly over the flange area for equal application of force and equally uniform engagement of the sections 23 with the groove bottoms. Because of such even and flat engagement, the projectile is centered in the barrel and does not yaw or tilt as occurs in the conventional projectiles so that a truer and more exact and accurate path of flight is imparted to the projectile after it leaves the gun barrel. In some instances, a very thin coating of some softer metal, such as a lead and tin alloy, may be applied to the outer surface of the projectile, not to form a coating into which the rifling lands may cut, but to provide a very thin lubricant type coating which may be of the order of thickness of a thousandth of an inch or so.
It is also to be noted that the angular configuration of the flanges 17, and especially the portions thereof repre sented by the bottom walls 15, form longitudinal support for the flanges and particularly for the lips 21 to resist any flexing or distortion of the flanges and the lips under the influence of the pressure exerted by the exploding propellant charge. At the same time, the uniform application of gas pressure from the explosive charge throughout the entire circumferences of the lips 21, hold the lips firmly, and necessarily the sections 22 and 23 of the surfaces 20, against both the groove bottoms and the lands of the gun rifling so that most effective guidance and rotational control is maintained, the sections 23 controlling the path of travel of the projectile and the notches 22 insuring the imparting of the proper rotational impetus thereto. This is in contrast to the conventional projectile in which the lands of the rifling control the rotational motion and primarily control the guidance of the projectile, the sections of the projectile between the grooves formed by the lands in many instances never coming into full and complete contact with the bottoms of the rifling grooves.
The angles of the faces and 16 of the flanges 17, as well as the angle of the lips 21, may be varied over a considerable range dependent upon the metal from which the projectile is formed, the performance characteristics desired of the projectile, and the nature or configuration of the lands and grooves of the rifling of the barrel through which the projectile is being fired. Thus, the faces 15 and 16 may be made greater or lesser acute with respect to the axis of the projectile so as to increase or decrease the longitudinal thickness of the flanges 17, and thus vary the force required to cut the notches 22 in the surface of the flanges. In all events, however, the general configuration illustrated in FIGS. 3 and 4 will be employed. The number of flanges and grooves employed as well as the longitudinal spacing thereof may also be varied to some extent, again, dependent on the particular projectile and gun barrel and the particular performance characteristics involved or desired.
Experimental firings of test projectiles made in accordance with this invention have shown that increased penetration is obtained over conventional projectiles of the same caliber and weight fired with the same type and loading of propellant charge and fired over the same testing distances. Fired at a distance of yards into semidry earth, the test projectiles displayed little or no deformation.
The invention may, of course, be applied to other types of projectiles such as the artillery shell illustrated in FIGS. 8 and 9. In such employment, the invention may desirably be applied by utilizing a greater number of the flanges and grooves, by increased angularity of the walls of the grooves, and by closer spacing of the flanges and grooves as indicated at 24 in FIG. 8 wherein there is shown an otherwise conventional artillery shell 25 having a nose cone or detonator 26 and a hollow interior 27 for reception of a suitable explosive charge or other conventional loading.
As to the relatively hard metals which may be employed in this new projectile, in contrast to the somewhat softer metals conventionally required, such metals must have a degree of ductility and should not be excessively brittle but this again is subject in some degree to the angularity of the flange faces, the nature of the projectile, and the type of barrel through which the projectile is to be fired, as well as other considerations such as the nature of the charge and the like. For instance, a C-10l8 open hearth carbon steel, cold drawn or rolled having a hardness of 13-85 Rockwell may be employed, a similar 0-1020 steel having a hardness of B-83 Rockwell, or a brass 13-70 Rockwell hardness.
The particular brass employed for test projectiles was a lead bearing alloy which required no coating although a very thin layer of a softer alloy, such as a lead tin antimony mixture, may be found desirable in some cases. The steel projectiles are preferably coated with such a material, or copper-plated, or coated with any of the alloys presently used for projectile jackets. It is to be noted, however, that this is a coating or plating with a very thin alloy layer for an anti-galling purpose, and not a jacketing.
It is further to be noted that when the flanged projectile is seated in its shell case there will be an initial sealing between the rearward flanges and the neck of the shell case which is maintained at least partially until the forward flanges enter the barrel rifling so as to minimize or eliminate gas blow-by occurring just as the projectile leaves the shell case.
All in all, the use of this flanged projectile in standard gun barrels has been found to result in performance and accuracy at least equal to that obtained from special, heavy match barrels and special match loads, and to provide firing patterns at least as small as those of much more expensive firearms and cartridges.
The foregoing description of the invention is explanatory thereof and various changes in the size, shape and materials, as well as in the details of the illustrated construction may be made, within the scope of the appended claims, without departing from the spirit of the invention.
What I claim and desire to secure by Letters Patent is:
1. A ballistic projectile adapted to be fired through a rifled gun barrel of substantially constant diameter comprising a projectile body having a solid nose section and a solid rearward portion with a body portion therebetween, and a multipicity of closely spaced annular flanges on at least the body portion and forming therebetween a multiplicity of narrow gas receiving chambers which are of the same volume before and after passage through a rifled gun barrel of substantially constant diameter whereby during such passage the pressure of the gas on opposite sides of each of the flanges is equalized, said flanges being of little radial width relative to the diameter of the body and having forward and rearward walls inclined forwardly and inwardly with respect to the axis of the projectile, at least the major portion of the rearward walls being at an angle substantially greater than that of the forward walls, said flanges being triangular in cross section and tapering from a relatively thick base portion to a relatively narrow apex so as to be substantially rigid and resist flexing of said flanges during passage of the projectile through the rifled gun barrel of substantially constant diameter, said flanges having uniform diameters substantially equal to the groove diameter of the gun barrel before and after passage therethrough and terminating at their apexes in narrow cylindrical faces which are parallel to the axis of the projectile for snug, flat faceto-face engagement with the bottom of the grooves of the gun barrel throughout their widths to maintain rotational balance of the projectile as it passes through the gun barrel.
2. A ballastic projectile as set forth in claim 1 further characterized in that each rearward wall has a portion adjacent the apex of its flange which terminates at an angle less than the angle of the major portion of the rearward wall of the flange and which coacts with the face of said flange to provide a rearwardly extending sealing lip for cooperating with the bottom of the grooves of the gun barrel to prevent the escape of the gas from the chambers.
References Cited in the file of this patent UNITED STATES PATENTS 1,944,885 Gerlich Ian. 30, 1934 2,110,264 Gerlich Mar. 8, 1938 FOREIGN PATENTS 7 783,789 France Apr. 15, 1935 OTHER REFERENCES Styles in Small Arms Projectiles, Army Ordnance, pages 395401, MayJune 1932.
Zinc Alloys, American Rifleman, January 1948, pages 23-26.