US2868130A - Ammunition - Google Patents

Description

J 1959 R. A. GULLEY ETAL 2,868,130

AMMUNITION Filed June 17, 1953 IN VEN TORS RONALD A (IaULLEYY THABUS a. H BY CHARLES M. SCHREIBER w Zu.

A GENT AMlVIUNITION Ronald A. Gulley, Jennings, Mo., and Thabus R. Harvey,

East Alton, and Charles M. Schreiber, Alton, 11]., assignors to Olin Mathieson Chemical Corporation, a corporation of Virginia Application June 17, 1953, Serial No. 362,336

3 Claiins. (Cl. 102-925) This invention relates generally to ammunition and more particularly to an improved cartridge and a novel projectile therefor.

Small arms, both rifles and pistols, such as caliber .22 are utilized extensively for target shooting as well as for hunting and plinking. Obviously, it is essential that the projectile fired from these guns strike the target at substantially the point at which the gun is aimed regardless of the nature of the target or the particular sport in which the shooter is participating. Competitive shooters at inanimate targets such as the popular bullseye target, however, probably become the most skillful and require the most accurate cartridge. Heretofore, such cartridges have been furnished for the most part either with a projectile of the shape disclosed in Figure 1 of U. S. Patent 1,892,759 having a rifling band near the posterior end thereof which is greater in diameter than the maximum diameter of the nose, or with a projectile having a rifling band equal in diameter to the maximum diameter of the nose such as disclosed in U. S. Patent 1,879,278. Although cartridges having projectiles of either of these types are usually suitable for most purposes, they cannot be consistently made to meet the accuracy requirements of the competitive target shooter. This is especially true if the cartridges are to be fired outdoors because either of these heretofore available projectiles is deflected appreciably from its intended path of flight by air currents.

It'is therefore an object of this invention to provide an improved cartridge having a novel projectile. It is another object of the invention to provide a cartridge with a projectile having improved ballistic characteristics. A

further object of the invention is to provide a cartridge with a projectile less susceptible to deflection by air currents than heretofore available projectiles. A still further object of the invention is to provide for small arms, and particularly caliber .22 arms, a projectile of novel shape having improved accuracy characteristics particularly under outdoor shooting conditions.

Further objects will become apparent from the following description with reference to the drawing in which Figure 1 is a longitudinal view partly in section of a cartridge embodying this invention, and

Figure 2 is a diagrammatic view with lines of construction of embodiments of this invention.

In accordance with this invention, the foregoing objects are attained by providing a cartridge with a projectile having a heel, a substantially prolate hemispheroidal nose and a rifling band of greater diameter than the greatest diameter of the nose and having a beveled anterior edge. Best results are obtained if the major axis of the closed curve, i. e. the ellipse, generating the hemispheroid are between about 1.6 and about 2.0 calibers and the minor about 0.8 and 1.0 caliber, and are preferably about 1.8 and about 0.9 caliber, respectively. The diameter of the rifling band is about one caliber in order to have a suitable fit with the rifling of the barrel and the 2,868,130 Patented Jan. 13, 1959 beveled anterior edge subtends an angle with the longitudinal axis of the projectile of not more than about 30 but preferably about 15. The heel of the projectile is adapted to form a friction fit with the inner wall of the mouth of'the cartridge case. The full length of the bullet is about 2.1 calibers and of this the axial length of the hemispheroidal nose occupies from about 0.8 to about 1 caliber, i. e. half of the major axis of the generating closed mathematical curve. Therefore the preferred point length is 0.9 of a caliber or half of 1.8 of a caliber. The rifling band presents as elongated cylindrical surface, as shown in the drawing of substantial axial length back of the anterior bevel in order to take the rifling of the gun barrel and to guide and support the projectile in its travel down the barrel. The heel preferably is of somewhat lesser diameter than the band to accommodate the mouth of a cartridge case and terminates in a concavity in the base.

Although,'a's stated he'reinbefore, the shape of the nose is substantially that of a'prol'ate hemispheroid, the shape of a preferred embodiment is modified to deviate from a true prolate hemispheroid to the extent that the nose terminates at itsanterior end in aspherical segment not greater than a hemisphere'andh'aving aradius less than 1.0 caliber, such as about0.4 of a caliber in particular. In Figure 2 of the drawing, which illustrates diagrammatically this embodiment, 24-represents the radius and the straight line 18 represents the base of the spherical segment forming the anterior edge. The preferred dimension of the base 18 of'the spherical segment is about 0.4 caliber and the radius 2@ of the sphere is preferably about 0.4 caliber. Thus, the solid conical angle subtended by the segment from its center of curvature is preferably one of about 60, although it is obvious that it may vary toa largr angle while the radius of the segment remains at about 0.4of a caliber. The solid curved line between points 25 and 26 represents the shape of the anteriorend of the projectile which terminates in a spherical segment having these dimensions. The broken line between 25 and 26, on the other hand, illustrates the anteriorend of a projectile which has a true prolate hemispheroidal shaped nose. In each instance the lines between 21 and 26 and between 22 and 25 representing the surface of the remainder of the projectiles nose are the lines of a-prolate hemispheroid having the dimensions stated in the foregoing paragraph. The broken line between 20 and 22 illustrates the angle 23 subtended by the beveled anterior edge of the rifling band with the longitudinal axis of the projectile. Substantially prolate hemispheroidal, as used herein and the appended claims, thus is inclusive of projectiles of true prolate hemispheroidal shape and of projectiles otherwise prolate hemispheroidal but terminating at their anterior end in the aforedescribed spherical segment. It is to be understood that any shape recognized as an approximation of a true prolate hemispheroid is also contemplated. A pure prolate hemispheroid will be recognized as the solid made when an ellipse is rotated about its major axis.

It has been found that cartridges of caliber .22 provided with the projectile of this invention are most accurate in flight, particularly in outdoor shooting, when fired from a cartridge adapted to propel the projectile at a muzzle velocity of not more than about 1150 feet per second or not less than about 1050 feet per second. The projectile is preferably provided with one or more annular grooves in the rifling band for the retention of any suitable lubricant such as, for example, grease, wax or similar lubricant and best results are obtained if the lubricant is confined to the surface of the rifling band and the prolate hemispheroidal shaped nose is maintained substantially free from any lubricant or similar material.

In order to better describe and to further clarify the invention, the following is a description of an embodiment thereof with reference to the accompanying drawing:

Cartridge case 1 of Figure 1 is of conventional rimfire caliber .22 design containing primer 3 and propellant 2 coordinated to propel at a muzzle velocity of about 1125 feet per second the projectile indicated broadly as 4. The projectile 4 is shaped from lead or other suitable metal to have a nose 5 terminating in a spherical segment 6 and to have a rifling band 7 composed of alternate rings and grooves 8, 10, 12 and 14 and 9, 11 and 13, respectively. The projectile terminates at the posterior end in heel 15 positioned in the mouth of case 1. The posterior end of heel 15 may or may not be concave, but is preferably concave as illustrated at 16.

The nose 5 of projectile 4 terminates at the anterior end in a segment 6 of a sphere having a radius of about 0.4 caliber and a base of about 0.4 caliber. Segment 6 forms about 2.8 percent of the total length of about 2.1 calibers of the projectile along its longitudinal axis. Nose 5 terminates at its posterior end in beveled edge 17 which extends therefrom to rifling band 7 intersecting annular ring 8 and subtending an angle of about 15 degrees with the longitudinal axis of the projectile. Annular grooves 9, 11 and 13 contain suitable lubricant and a film of lubricant may coat the annular rings 8, 10 and 12 but nose 5 is preferably substantially free from any lubricant.

The beveled edge 17 of the projectile can be formed as the projectile is shaped by molding or swaging. Preferably, however, the projectile is formed first with the rifling band having an anterior edge approximately perpendicular to the surface of the band and this perpendicular edge is subsequently rolled or otherwise compressed to form the beveled edge. Inasmuch as lead projectiles are relatively soft and thus easily damaged it is ordinarily better to form the beveled edge on the projectile after it has been inserted in the cartridge case.

The projectiles of cartridges embodying this invention consistently strike the target nearer the point of aim than do cartridges having projectiles of other shapes such as projectiles having a nose which terminates into a perpendicular anterior edge of a rifling band of greater diameter such as shown in U. S. Patent 1,892,759. The cartridges embodying this invention are also more accurate than cartridges provided with projectiles having a profile similar to the projectile disclosed in U. S. Patent 1,879,278 and projectiles having a nose terminating more bluntly such as terminating with a flat anterior end. This improvement is apparent in indoor shooting but is even more pronounced when cartridges are fired over an outdoor range.

In outdoor shooting, the projectile is deflected from its intended path of flight by practically any wind or 4 other air current encountered between the rifle muzzle and the target. It has been found that the projectile of this invention is deflected less than the heretofore commercially available projectiles. For example, on one particular test it was found that the average deflection of the projectile of this invention from its intended path of flight at a distance of about yards from the rifle muzzle was 1.89 inches, while the average deflection of projectiles having a rifling band with a perpendicular anterior edge was 2.13 inches. In a similar test, the deflection of the average projectiles having a rifling band substantially equal in diameter to that of the posterior end of the nose was 2.02 inches. Furthermore, because the embodiments of this invention are inherently more accurate than heretofore manufactured projectiles, a larger percentage of the projectiles produced meet rigid manufacturing requirements and thus the amount of scrap and the accompanying production costs are reduced.

While the invention has been described in detail in the foregoing, this description is for the purpose of illustration only and variations can be made therein within the skill of the art without departing from the spirit and scope of the invention except as limited by the appended claims.

What is claimed and desired to secure by Letters Patent is:

1. A small arms projectile comprising a heel, a substantially prolate hemispheroidal nose having a length of between substantially 0.8 of a caliber and one caliber and having a greatest nose diameter of between substan tially 0.8 of a caliber and one caliber and intermediate said heel and nose a rifling band including a cylindrical portion of substantial length and of a diameter of substantially one caliber, said band diameter being greater than said greatest nose diameter and said band having an anterior edge tapering from said cylindrical portion to said greatest nose diameter to subtend an angle between substantially 15 and 30 with the longitudinal aXis of the projectile, said projectile having a length of about 2.1 of a caliber.

2. The projectile of claim 1 wherein the nose has a length of substantially 0.9 of a caliber and a greatest diameter of substantially 0.9 of a caliber and wherein the anterior edge subtends an angle of substantially 15.

3. The projectile of claim 2 wherein the tip of the nose is a spherical segment having a base diameter and a radius both substantially 0.4 of a caliber respectively.

References Cited in the file of this patent UNITED STATES PATENTS 15,141 Maynard June 17, 1856 1,187,867 Shinkle June 20, 1916 1,455,354 Porter May 15, 1923 1,879,278 Jacobs Sept. 27, 1932 FOREIGN PATENTS 503,198 France Mar. 11, 1920

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