US1355422A - Rifle-barrel - Google Patents

Description

J. D. PEDERSEN.

RIFLE BARREL,

Patented 0013. 12, 1920.

APPLICATION FILED JULY 1,855,422.

UNITED STATES JOHN D. PEDEBS'EN, 0F JACKSON, WYOMING.

RIFLE-BARREL.

Specification of Letters Patent.

Patented Oct. 12, 1920.

Application filed July 14, 1917, Serial No. 180,492. Renewed March 22, 1919. Serial No. 284,516.

T 0 all whom it may concern.

Be it known that JOHN D. PEDERsEN, a citizen of the United States, residin in Jackson, inthe'county of Lincoln and S nate of Wyoining, have invented certain new and useful Improvements in Rifle-Barrels, of which the following is a specification.

This invention relates to rifle barrels, and a principal object is to furnish an improved barrel especially adapted'for use in rifled shoulder arms. A further object is to provide means whereby the work of finally shaping the projectile to conform to and engage with the rifling ribs and in the rifling grooves, will be accomplished in successive stages or periods, so that said work will be 7 carried out in the rearward portion of the barrel and also in a modulated and progressive manner. p

As regards some features thereof, my present invention, is in the nature of a modification of, and an improvement on therlfle barrel described in my copending applica-, tion Serial No. 177,252, filed June 27, 1917; some features, however, of the improved rifle barrel herein described are regarded as being within the description, and as being covered by certain of the claims of said prior application. 7

i particular purpose of the present invention is to furnish a rifled gun barrel especially adapted for using un-cased (or thinly cased or coated) projectiles,such as bul lets of lead or those of similar character,-

in a highly effective manner, and therefore to provide for propelling such projectiles,

. oibullets, with powder charges of relatively high power; also,.to accomplish these results in connection with a firearm barrel,-such for instance as the barrelof a military shoulder-arm -in which the riflingis of a standard'form and construction suitable for using encased projectiles of the usual elongated form. Further advantages and objects are "the following description.

pointed out and explained in the course of In the drawings accompanying and forma "inga part of this specification, Figurelis a. side view,principally in section, and barrel made in accordance with my present improvements, and of composite construe with some parts broken away,of a--rifle 1 tion.-

' Fig. 2 is an end view, as seen from the left-hand in Fig. 1.

Figs; 3 and 4: are cross sections in lines X and K, respectively, of Fig. 1; Figs. 3 and 4 are end views (on an enlarged scale) of a projectile at successive "stages of the surface formation thereof, as effected by the successive riflings shown in Figs. 3 and 4, respectively. I

' Fig. 5 is an enlarged detail view especially arranged for illustrating certain features of the rifling, as hereinafter more fully explained.

F'g. 6 is a view analogous to a portion of Fig. 1, for illustrating certainvariations in v the form or arrangement of successive portions of" the rifling.

Similar reference characters designate like parts in all the views. I

Referring to the drawings, B indicates a rifle barrel of ordinary character; it may have, in practice, any desired or suitable external size and form. To facilitate illustration, a large portion of the length is broken away at 20, in Fig. 1, so that the rearward barrel of the class common to military shoulder arms; These barrels are now generally made with the bore thereof,-as E,

Fig. 1,-having a diameter of about three- 1 tenths. of one inch, but in practice this bore may be smaller or larger, as may be required bythe size and character of the firearm.

The main barrel, B, may be provided with the usual form of helical rifling, either of uniform twist, or gain twvist, as may be desired';- however, I prefer to use in this barrel the. more. common uniform twist. The number of the rifiing ribs may vary, three to six being within common practice, but'I prefer, for general use, to have the barrel B provided with four ribs, as 5,- see Figs l, 4, 5 and 6. To aid clearness of illustration, the usual depth of the rifling grooves, 5",- (Fig. 4), (and, of course, the

height of. the rifling ribs 5), has. been somewhat exaggerated in the present drawing. Said depth of grooves and height of ribs are, of course, to be measured in a direction radial to the geometric axis of the barreL- At the rearward end thereof, the barrel :B," (,Fig. 1), is shown at ,10, externally reduced in size and threaded, by way of showing one ordinary wa. whereby the barrel may be removabl xed in the usual receiver, or frame, hot shown) of a firearm,

. in 'a well-known manner. Also, said main barrel B is shown as being bored out, (to

the lines. 12, 12, Fig. 1), to form the usual cartridge chamber, suitable for the shell, or powder-case]? (not shown) of a high- 1 power cartridge having a long-range prosame size and proportions as the chamber 12,

' jecetile.

the member D will not beremovable.

in my Into said chamber'12, a secondary barrel, D, isshown closely fitted, thus forming a complete barrel having a composite construction. It should be understood, howu ever, that in some instances, if desired, said portion orauxiliarybarrel, D, may be made integral with the main barrel, B; in this case, of course, the barrel B will have no chamber 12 available for separate use, since an integral form of the completebarrel is not shown herein, but has been illustrated aforesaid application Serial No. 177,252.

In the composite form of the barrel shown in Figs. 1, 2, 3 and 6, the member D is ex-. tended rearwardly of the member B, (Figs. 1, 2), and is there shown enlarged, as at 14, and provided with a cartridge chamber15;

this chamber should be of suitable size and proportions for receiving the cartridges which, in any given instance, are to be used 1n the composite barrel. 'Said chamber 15, 111801116 instances if desired, may be of the relatively small rifling ribs for initially grooving a projectile, and which forward of said small ribs, (and forward of said'zone N '1 of the intial projectile gro oving action), is

provided with rifling rribs arranged for changing the initial grooving ofthe projec, tile. A further feature is that said zone ,N

of initial grooving, is extended forwardly from said chamber 15 to a length or bint forwardo'f the'position when the gases nor:

Such

mally will have reached their maximum pressure, so that the projectile will pass from the relatively small to the larger rifling ribs at a time when the as-pressure is beginning to decrease; durlng this period,- or time-interval,-i't is believed that the velocity of the projectile will bemost rapidly increasing. This increase, however, of velocity is supposed to disappear at or somethereof of a diameter larger than the diame-'.

ter of the bore of the main barrel, and is' also shown provided with rifling ribs, as 7 swith intervening grooves 7 ;-which are not only smaller and more numerous than the ribs 5 of the main barrel, but are also located farther from the geometric axis of the barrel. In practice, the number of the ribs-7 relative to the number of the ribs 5, may be varied, but I prefer to make said smaller ribs about double the number of the larger ribs; such an arrangement is shown-in Fig. 5, where the four large ribs 5. are shown used in combination with eight of the smaller ribs 7. This arrangement and construction I have found by practical tests to be particularly effective in operation. 1

In Fig. 5 a further feature is illustrated,

' in that the outer circle, at 31,-ofthe ribs 5 and grooves 5", of the main rifling, is also substantially coincident with the inner circle of the ribs 7 and grooves 7 of the 'auxlli'ary rifling. Thus it may be said that the two series of ribs and grooves,-as seen in an endview of the barrel,occupy two concentric annular zones, respectively, the r1bs 7 being in the outer zone indicated by the circles at 31 and 32, and the ribs 5 being in the inner annular zoneindicated by the circles at 30 and 31, Fig. 5. A pair of the small ribs 7 are also shown in Fig. 5 located in a symmetrical position circumferentially with relation to each one of the larger ribs 5, but

in-"practice, this-symmetry of arrangement,

while regarded as preferable, may be omitted in some instances. In this view, Fig. 5, of

course 'thecervature, or spirality, of the ribs is disregarded.

In Fig. 1, the ribs 7 are indicated as extending forward close to the rearward ends of the larger ribs 5,'but it should be under"- stood that in some instances if desired, a

space, or un-ribbed zone, as 8', Fig. 6, may

for the complete barrel. By its motion and e great momentum acquired in traversing the zone N, the projectile will readily pass from the ribs 7 and over said zone 8 andcontinue '1 30 ing with the rifling 5. Thus the small projecting ribs (F ig. 3 raised on the projectile by the small ri ing-ribs 7 may be reduced,

' or ironed out by the cylindrical surface of the bore within the zone 8'.

In the zone z,Figs. 1, 6,the ribs 5 are shown tapered or reduced to a wedge-like form, thus providing for a gradual engagement of the projectile with said ribs, and

avoiding so sudden a shock or resistance as otherwise might occur; this tapering form of the rib-ends of the rifling 5 may, how

- ever, be omitted in some instances, whenever stage of'the combustion of the powder. Consequently, during that initial forward move-' spondingly increase thegas-space beforejthe desired, and is not essential to the principal features of my present invention.

The relativeeifects of the successive rifling ribs, Tand 5, upon a projectile are approximately shown in Figs. 3? andi l which correspond with the inner outlines of the bore of the barrel, in Figs. 3 and 4, respectively. Thus Fig. 3 shows a cross-section of a projectile, J, as initially by the ribs 7 Fig. 3, to form the initial ribs 7 on the projectile. Similarly, Fig. 4: shows said projectile as having formed therein the new and larger grooves, 5 corresponding to the ribs, 5, of the barrel B,

i in Fig. 4; in this latter operation, the initially-formed ribs on the projectile,Fig. 3*,are reduced and eliminated by a-complete re-forming of the outer surface-portion of the projectile.

The slight resistance offered by the relatively small ribs 7 to the initial forward movement of the rojectile, permits this movement,-,on the ringof a cartridge,- to begin at a time (at a moment) when the gas-pressure is-still comparatively ,low, so that the space behind the projectile will be materially enlarged during a very early ment, the projectile will havenot only a-low velocity, but also, for the instant, a low degree of: acceleration, so that a minimum amount of power will-be consumed durin that moment in inaugurating the rotation-o the. projectile, and thereby permit'a -more rapid acceleration of the forward movement under agiven and relatively low gas pressure. Thus the rapidly increasing forward movement while the projectile is'subjected to the low rib-resistance, -tends to corregas-pressure' can rise to its maximum. As a result of this action, the curve by which the ga's-pressure is usually represented in a wellknown diagrammatic manner, Wlll be materially modified in a way to'show a delay,-- as compared with the hitherto accepted prac- .tice, vof the moment when the gas will attain maximum pressure; this normally operates to reduce the maximum strain upon the barrel due to the burning therein of a given quantity'of powder behind a projectile of a given weight, and also,w ithin a given limit of that strain,provides for burning a relatively larger quantity ofpowder behind a projectile of a given weight. 1

By reason of'the, modulation, as above explained, of the forces and pressures, the torsional strain on the initial rifling (and especially during the first one or two inches of said forward movement of the projectile), is believed to be materially less than normally occurring with the usual style of rifling which has ribs-of uniform cross-section dimensions throughout the length of the barrel. Hence my present improvements are especially applicable to rifled firearms hav- .85 ing barrels of composite construction, and in which a main barrel is adapted for using high-power cartridges and is also, for some uses, provided with an adapter, the bore of which forms a rearward extension of tl1e-.90 bore of the main barrel; one arm of this class,a military shoulder-arm,is described in m application filed April 28th, 1917, Serial 0. 165,171, towhich reference may be had. In practice, by the time'when the projectile has reached the forward end of the initial ribs 7 and thus come to the larger rifling ribs 5, the projectile has acquired such a I velocity and momentum that it will take the riding. of the main barrel without difliculty. As a result, therefore, of,the said features and mode of action, when the barrel is provided with the relatively thin adapter extension or supplemental barrel, as herein shown, this is so far protected and relieved of the otherwise heavy straix'nas to be reliable and effective under the severe conditions of continued service. ,Thus, also, I avoid the highly destructive action upon the pro- 11. jectile, which occurs when the bore of the adapter-barrel is a smooth-bore (not herein shown); that construction, asI have found by extended trials; allows the projectile to initially advance toov rapidly, so that on striking the rifling ribs of the main barrel,-

and being then without rotation,-the projectile will often be so cut'and deformed as j greater than that of the well-known risingpressure zone of a pressure-diagram for the cartridges proper for use in the barrel B, so" that,as herein 'explained,the increased resistance due to the projectile encountering the larger ribs 5, will be delayed, and so will notoccur until after the gas-pressure has begun to reduce. The minimumdength of the zone N may be regarded as equal to about two and one-half times the diameter of the bore E, while a normal and preferable range thereof may be between four and ten diameters or calibers, according to size of bore, the twist of the rifling, and the character and power of the cartridges to be used; all these matters or factors are readily ascertainable by trial in any particular instance.

'The breaking of the surface of the bullet into small undulations by the action of the rifling ribs 7, serves to prepare the bullet for the second and larger change of form which is effected by the main rifling 5. Thus a it may be said that the rotation of the bullet is effected first by means of a temporary, and preliminary formation thereof, and is then continued by means of-a second and different formation thereof. The rotation is inaugurated'by the auxiliary rifling 7, acting upon the small ribs, as 7", of the bullet Y J,-as indicated in Fig. 3 ,and the rotation is accelerated and continued by the main rifling, 5, acting upon the larger ribs, 7, (Fig. 4'), which are formed on the bullet after said preliminary formation thereof has been obliterated. Thus the initial grooving of. the projectile is normally followed by the re-grooving thereof, and this is accompanied by a reduction of the outside diameter,and sometimes by a slight elongation,as now will be readily understood by a comparison of the several circles at 30, 31 and 32,- and of Figs. 3 to 5, inclusive. In some instances, if desired, especially in firearm barrels of larger bore,the inner circle of the initial grooving may be slightly smaller than the outer circle of the final grooving of the bullet; however, I deem it to be desirable that in the initial grooving operation, the ribs 7 shall not cut so deeply into the bullet but that the final grooving operation will fully smoothout, or seal, the initially-formed ribs and grooves of the bullet. When these operations are properly carried out, the

, symmetrical arrangement of the ribs 7 and 5,-as already described in connection with Fig. 5,-becomes relatively unimportant, so that the member D may in practice be turned to have any desired position relative to and within themember B.

Having thus described myinvention, 1

claim 1. A rifle barrel having in the rear end thereof a cartridge chamber, and having a bore which in a zone thereof adjoining said chamber is provided with 'a series of rifling ribs arranged for initially grooving a projectile with one number of grooves, and

which forward of said initially-grooving ribs is provided with another series of rifling ribs that are in position and adapted r51" first obliterating the initial grooving and for then re -grooving the projectile with a different grooving.

'ferent series of grooves,

which forward of said initially-grooving ribs is provided with rifling ribs of a number less than the number of said initial rifling ribs, and that are in position and adapted for first obliterating the initial grooving and for then re-grooving the projectile with a different grooving.

3. A rifle barrel having a cartridge cham ber and having forwardly from said cham-- ber a bore which in a zone thereof adjacent to said chamber is provided with a relatively numerous series of rifling ribs for initially forming on the projectile a numerous series of relatively small ribs and grooves, and which forward of said zone is provided with a different and less numerous series of rifling ribs arranged for forming on the projectile a different and less numerous series of relatively larger ribs and grooves.

l. A rifle barrel having a cartridge chainber, and having forwardly from said chamber a bore which in a zone thereof adjoining said chamber is provided with a series of rifling ribs for initially grooving a projec tile with one number of grooves, and which forward of said zone is provided with rifling ribs that are in position and arranged for re-grooving the projectile with a different number of different grooves, the rifling ribs in said zone having the inner circle thereof of a diameter larger than the diameter of thg, inner circle of said re-grooving riflin r1 s.

5. A rifle barrel having a cartridge chamber, and having forwardly from said cham ber a bore which in a zone thereof adjoining said chamber is provided with a series of relatively small rifling ribs for initially grooving a projectile, and which forward of said zone is provided with a series of larger rifling ribs that are in position and arranged for re-grooving the projectile with a difsaid series of smalle'rrifling ribs having the inner circle thereof of a diameter larger than the diameter of the inner circle of said series of larger rifling'ribs.

6. Arifle barrel having a cartridge chamber, and having a bore. which in a zone thereof adjoining said chamber is-provided with relatively small and numerous rifling ribs arranged for initially grooving a projectile, and which forward of said small ribs is provided-with larger and less numerous rifling ribs that are in position and adapted for obliterating said initial grooving and for then re-grooving' the projectile. i I

berfand having a bore which in a zone thereof adjoining said, chamber is provided with a series of relatively small and numerous rifling ribs arranged for initially grooving a projectile, and which forward of said small-ribs is, provided with a series of larger and less numerous rifiing ribs that are in position and adapted for obliterating said initial grooving and for -then re-grooving the projectile, said series of the smaller rifling ribs having'the inner circle, thereof of a diameter: larger -than the diameter of the inner circle of said series of the larger rifling ribs.

8. A rifle barrel ofeomposite construction and having a continuous bore, and comprising a main barrel having at the rear end thereof a short secondary barrel provided with a cartridge chamber, and adjacent to said chamber provided with a series of relatively small rifling ribs for initially grooving a projectile with one number of grooves,

said main barrel at a distance forward ofsaid small ribs being provided with a different series of relatively larger rifling ribs that are in position and adapted to regroove the projectile with a different grooving.

9. The hereindescribed improvement in composite rifle barrels, it comprising a main barrel having in the bore thereof a series of rifling ribs, and having a cartridge chamber in the rearward end thereof, in combination with a secondary barrel having the forward end thereof removably. inclosed insaid cartridge chamber of the main bar: rel, and having in the rearward end there of and rearward of the main barrel a car tridge chamber and in the bore thereof having a series of rifling ribs for initially grooving a projectile with one number of grooves, said main barrel having the bore thereof of a diameter smaller than the diameter of the bore of the secondary barrel.

JOHN D. PEDERSEN.

Witnesses:

L. E.-WETMORE, E. C. GILBERT.

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