US3786589A

US3786589A - Barrels for rifles and pistols with running lands and grooves

Info

Publication number: US3786589A
Application number: US00153207A
Authority: US
Inventors: H Kaltmann
Original assignee: Rheinmetall GmbH
Current assignee: Rheinmetall Industrie AG
Priority date: 1970-06-18
Filing date: 1971-06-15
Publication date: 1974-01-22
Anticipated expiration: 1991-01-22
Also published as: NL7106303A; CH536478A; IL36764A; IL36764A0; DE2029877A1

Abstract

A barrel for rifles and pistols equipped with lands and grooves, wherein the greatest measure of the groove caliber of the barrel corresponds with the minimum measure of the diameter of the projectile, and the land caliber amounts to about 96 percent of the groove caliber.

Description

O Umted States Patent 1 1 3,786,589 Kaltmann 1 Jan. 22, 1974 [54] BARRELS FOR RIFLES AND PISTOLS 2,293,114 8/ 1942 Carter 42/78 WITH RUNNING LANDS AND GROOVES 3,100,358 8/1963 Robinson, Jr... 42/78 3,562,945 2/1971 Mikola 42/78 [75] Inventor: Hans-Joachi tmann, 3,643,364 2/1972 Koch 4217s Dusseldorf, Germany N F PA [73] Assignee: Rheinmetall GmbH, Dusseldorf, OREIG TENTS F APPLICATIONS Germany 3,166 12/1861 Great Bntatn 42/78 [22] Filed: June 1971 Primary Examiner--Benjamin A. Borchelt [21] Appl. No.: 153,207 Assistant Examiner-C. T. Jordan Attorney, Agent, or Firm-Ernest G. Montague [30] Foreign Application Priority Data June 18, 1970 Germany 2029877 [57] ABSTRACT [52] us CL u 42/78 A barrel for rifles and pistols equipped with lands and [5]] In; CL 17/10 grooves, wherein the greatest measure of the groove [58] Field of 42/78 caliber of the barrel corresponds with the minimum measure of the diameter of the projectile, and the land I 56] References Cited caliber amounts to about 96 percent of the groove cal- UNITED STATES PATENTS 1,275,028 8/1918 Holter 42/78 3 Claims, 2 Drawing Figures ,IIIII Iln- I KN 1 I e 1 a Q a t *7 G 5 1 7 K "*I'IIII PATENTEI] JAN 2 2 I974 SHEET 2 IF BARRELS FOR RIFLES AND PISTOLS WITH RUNNING LANDS AND GROOVES The present invention relates to a barrel for rifles and pistols with running lands and grooves, from which projectiles can be shot without a guide band.

In conventional manner the barrels of these rifles or pistols have a groove profile formed of grooves and lands, whereby during firing in the barrel already a rota 'y movement is imparted about its longitudinal axis to the projectile. The groove caliber takes into consideration thereby in general the tolerance of the diameter of the projectile and corresponds mostly with its high- 'est dimension. The land caliber, that means, the open distance between the lands, is thereby smaller than the diameter of the projectile. The lands serve as guide faces for the projectile, while the twist is imparted to the projectile.

In connection with rifles and pistols, one is always desirous to improve the outputof the rifle or pistol in relation to the most important factors. These are the operating life of the barrels, the firing range of the rifle or pistol and the target picture. All three factors are dependent, in addition upon the material of the barrel and the characteristic of its inner face, first of all, upon the formation of the caliber, that means upon the profile cross section.

A great problem is caused, for some time, in the formation of the profile cross section. At the transfers from the landsinto the grooves remain namely small cross sectional faces which are not filled by the projectile. At those places, parts of the powder gases can escape passing the projectile, whereby the powder gases are not fully exploited. The hot powder gases flowing through the narrow splits with high speed cause high wear of the inner wall of the barrel, whereby in a comparatively short time period, the firing range and the obtained target pictures become unsatisfactory. Itihas been recognized by the experts in the field, that in relation to the observed disadvantages improvements can be obtained, if one avoids sharp transfers on the lands to the grooves. By this arrangement, in the first place, a takeoff from the jacket face of the projectile is avoided. Furthermore, within the frame work of these recognitions, a plurality of proposals have been made for avoidance of these disadvantages. It has been already proposed to form the profile cross section of a rifle? harrelas a polygon with rounded edges, whereby grpoves and, lands run into each other without edges. In accordance with another known proposal, the lands should comprise chords in a circle and the grooves should comprise sections of this circle.

Theknown proposals exhaust themselves, however, mostly only in general information, without giving a definite lesson, 1h0W to design and to dimension the grooves and lands. Thus, experiments for the realization of these general proposals in different firearms did notonly not bring about the desired results or only apparent results, by achieving either a lower wear at the expense of the target picture or of the firing range, or vice versa. This lies first of all in the fact that the set requirements influence each other in an opposite sense and further also in the fact that the conventional production tolerances, which amount in rifles and pistols of this order from about 0.02 to 0.03 mm., have not been considered.

It is therefore one object of the present invention to provide a barrel for rifles and pistols, which is characterized on the one hand by an increased firing range, as well as by a good target picture and, on the other hand, by an increased operational life.

Based on the old recognitions found by experts in the field, it is another object of the present invention, starting with a barrel equipped with grooves and lands, wherein the highest measure of the groove caliber corresponds with the minimum measure of the diameter of the projectile and the land caliber amounts to about 96 percent of the groove caliber. By such dimension of the profile cross section, appreciable improvements of the rifle or the pistol concerning the target image, the firing range, and the operational life are obtained.

Now, the requirements set to the rifle or pistol are different, depending upon the use of the rifle or pistol. Thus, for example, in case of a sporting gun the obtainable target picture is the main requirement, while in an infantry gun with increased barrel wear, the longer life is to be considered the main requirement, with extensive improvement also of the other values. Within the framework of the present invention, it is now possible, by stronger consideration of one or the other factor, to adjust a profile cross section of the barrel to the intended use of the firearm.

For a gun with which in the first place an extremely good target picture is to be obtained, one uses advantageously a barrel equipped with four lands and grooves each, which barrel is characterized by the feature, that the grooves or lands consist in known manner of sections of a circular arc, the radius of which corresponds with the radius of the minimum diameter of the projectile and the lands comprise chords in this circle. Jointly with the dimensioning of the calibers in accordance with the main feature of the present invention, such barrel is destined in the first place for the use in connection with sporting guns.

For a gun the barrel of which should have in addition to a good target picture, first of all, a high operational life, one provides suitably a profile with three grooves, to which are oppositely disposed three lands. In the use of the teaching of the present invention, the grooves and lands comprise sections of a circular arc, the radius of which corresponds with that of the minimum diameter of the projectile, and the lands comprise circular arcs, the radius of which is about 14-18 percent larger than the radius of the minimum diameter of the projectile. A barrel equipped with this profile is thus in the first place destined for the use of guns with increased barrel wear, that means for infantry guns.

With these and other objects in view, which will become apparent in the following detailed description, the present invention, which is shown by example only, will be clearly understood in connection with the accompanying drawings, in which:

FIG. 1 is a profile cross section with four lands and grooves and FIG. 2 is a profile cross section with three lands and grooves.

Referring now to the drawings and in particular to FIG. 1, the profile cross section disclosed in FIG. 1 has four grooves Z and lands F and in the first place is destincd for barrels of sporting guns, in which the obtaining of a good target picture is the main requirement. In a circle with the radius Rz, which corresponds with the radius of the minimum diameter G of the projectile, the

lands F are disposed symmetrically, which comprise chords in this circle. The grooves Z are sections of this circle. The transfers from the lands to the lands or grooves are rounded up with the avoidance of edges. During producing of the barrels it is to be observed, that the greatest measure of the groove caliber corresponds with the minimum measure G of the diameter of the projectile and the land caliber amounts to about 96 percent of the groove caliber.

The profile cross section, disclosed in FIG. 2, has three grooves Z, to which three lands F are opposed. This profile is destined in the first place for guns with a great barrel wear, thus, for infantry guns. The grooves Z comprise sections of a circle with the radius R which corresponds with that of the minimum diameter of the projectile G. The land caliber K corresponds again to about 96 percent of the groove caliber K and the lands are formed of circular arcs, the radius R; is about l4-l8 percent larger than the radius R of the minimum diameter of the projectile. Here also is to be observed, that the greatest measure of the groove caliber K corresponds with the minimum measure G of the diameter of the projectile.

The measuring rules of the invention are explained below in connection 'with a calculation example for FIGS. 1 and 2, whereby FIG. 1 is to be destined the protile for a sporting rifle or sporting pistol for cartridges of the caliber 7X64. The minimum diameter G of the projectile amounts in this projectile to 7.22 mm. This measure forms simultaneously the greatest measure of the groove caliber K The land caliber K, amounts to 96 percent of the groove caliber, thus 6.93 mm.

The profile in accordance with FIG. 2 is destined for an infantry gun of NATO caliber 7.62X l.

The minimum diameter G for the projectile of this ammunition amounts to 7.80 mm., which measure is simultaneously the highest measure of the groove caliber. The land caliber K amounts to 96 percent thereof, thus 7.488 mm. The radius R of the circular arc sections forming the grooves amounts thus to 3.9 mm. and the radius R of the circular arc sections forming the lands amounts to about 4.52 mm.

While I have disclosed several embodiments of the present invention, it is to be understood, that these embodiments are given by example only and not in a limiting sense.

I claim:

1. A combination of a barrel for rifles and pistols and a plurality of projectiles to be used therewith, comprising a plurality of projectiles, said projectiles ranging from a minimum projectile diameter to a maximum projectile diameter,

a barrel equipped with lands and grooves, said grooves having their largest diameter equal to the minimum diameter of said projectile, and

the caliber of said lands being about 96 percent of the diameter of said grooves.

2. The barrel, as set forth in claim 1, which includes four lands and grooves,

said grooves comprise sections of a circular arc, the radius of which corresponds with the radius of the minimum diameter of said projectile, and

said lands comprise chords in a circle.

3. A barrel for rifles and pistols equipped with lands and grooves, wherein thegreatest measure of the groove caliber of said barrel corresponds with the minimum measure of the diameter of a projectile,

the land caliber amounts to about 96 percent of said groove caliber,

said grooves comprise three grooves, to which the lands are opposed,

said grooves comprise sections of a circular arc having the radius of said minimum diameter of said projectile, and

said lands comprise circular arcs, the radius of which is about 14-18 percent larger than the radius of said minimum diameter of said projectile.

Claims

1. A combination of a barrel for rifles and pistols and a plurality of projectiles to be used therewith, comprising a plurality of projectiles, said projectiles ranging from a minimum projectile diameter to a maximum projectile diameter, a barrel equipped with lands and grooves, said grooves having their largest diameter equal to the minimum diameter of said projectile, and the caliber of said lands being about 96 percent of the diameter of said grooves.

2. The barrel, as set forth in claim 1, which includes four lands and grooves, said grooves comprise sections of a circular arc, the radius of which corresponds with the radius of the minimum diameter of said projectile, and said lands comprise chords in a circle.

3. A barrel for rifles and pistols equipped with lands and grooves, wherein the greatest measure of the groove caliber of said barrel corresponds with the minimum measure of the diameter of a projectile, the land caliber amounts to about 96 percent of said groove caliber, said grooves comprise three grooves, to which the lands are opposed, said grooves comprise sections of a circular arc having the radius of said minimum diameter of said projectile, and said lands comprise circular arcs, the radius of which is about 14-18 percent larger than the radius of said minimum diameter of said projectile.