US3731418A

US3731418A - Small firearms with exchangeable barrel

Info

Publication number: US3731418A
Application number: US00126441A
Authority: US
Inventors: M Birkenhagen; M Birkenaen
Original assignee: JP Sauer and Sohn Machinenbau GmbH
Current assignee: JP Sauer and Sohn Machinenbau GmbH
Priority date: 1970-11-25
Filing date: 1971-03-22
Publication date: 1973-05-08
Anticipated expiration: 1990-05-08
Also published as: DE2057995C3; DE2057995A1; JPS5627798B1; DE2057995B2

Abstract

An apparatus for detachably securing a firearm barrel with a receiver flange of a receiver assembly and characterized in that the receiver flange is longitudinally slit so as to permit the flange to be circumferentially constricted into clamping engagement with the barrel.

Description

ite tates Patent irkenhageh et al.

SMALL FIREARMS WITH EXCHANGEABLE BARREL Manfred Birkenhagen, Eckernforde, Germany; Manfred Birkenaen, Eckernforde, Germany Inventors:

Assignee: J. P. Sauer & Sohn GmbH, Eckernforde, Germany Filed: Mar. 22, 1971 Appl. No.: 126,441

Foreign Application Priority Data Nov. 25, 1970 Germany ..P 20 57 995.7

U.S. C1. ..42/75 1; Int. Cl ..F4lc 21/00, F411. 23/00 Field of Search ..42/75 B, 75 A, 77;

Primary Examiner-Benjamin A. Borchelt Assistant ExaminerC. T. Jordan Attorney-Burns, Doane, Swecker & Mathis [57] ABSTRACT An apparatus for detachably securing a firearm barrel with a receiver flange of a receiver assembly and characterized in that the receiver flange is longitudinally slit so as to permit the flange to be circumferentially constricted into clamping engagement with the barrel.

12 Claims, 8 Drawing Figures SMALL FIREARMS WITH EXCHANGEABLE BARREL GENERAL BACKGROUND, OBJECTS, AND

SUMMARY OF INVENTION The invention relates to a gun with exchangeable barrel and in which the barrel rear end is inserted releasably in a corresponding recess of a receiver flange with an axial stop.

Customarily the barrel and the casing, or receiver, of small arms, especially guns, are connected with each other by means of a self-locking attaching thread. Since this connection must be very tight because it influences the performance of the firearm, it is not possible by simple means to exchange the barrel of the firearm without there being the necessity afterwards of reworking" the firearm and zeroing it in again.

A construction has been known where basically the exchange of the barrel with simple means is possible without subsequent reworking, whereby, however, the receiver flange, screwed tightly with the barrel, is separate from the remaining body of the receiver. In that case, however, the barrel is screwed together with the receiver and stock by means of two screws, as a result of which the vibrations of the barrel developing during cartridge detonation will be prevented from spreading freely. According to experience, however, the pre-supposition for good performance and for a constant alignment entails a freely vibrating or unrestrained barrel.

The present invention is based on the object of producing a gun with an exchangeable barrel, where the exchange of the barrel is possible with the help of a simple tool without special auxiliary devices. Under certain circumstances, it is possible, without any tool, to effect such an exchange. Beyond this, no reworking is necessary after the exchange and, further-more, the performance of the gun and the future position of the firearm will not be influenced disadvantageously. Further, this invention recognizes that one must avoid an arrangement wherein, because of a connection between the barrel and the front part of the stock via a second attaching screw, the working of the woodof the front part of the stock could have an adverse effect on the future position of the firearm.

According to the invention this problem is solved, in the case of a gun of the above mentioned type, by the fact that the receiver flange has a longitudinal slit in its bottom side, developed in a reinforced manner as a support and facing the stock, and that tightening elements will tighten the sides releasably facing each other along the longitudinal slit.

Therefore, a gun has been produced where the barrel can be quickly exchanged for another one with a different caliber and which also can be quickly and simply disassembled for the purpose of transportation. In this way a requirement will be met which in the case of drop barrel guns has been satisfactory for decades but, which in the case of repeater rifles, however, has not been satisfactory heretofore because of a difierent type of con-struction. The gunner will now be able to shoot with his gun shells of different calibers. He does not need to become accustomed therefore to other dimensions of the stock all over again and will not be influenced as a result in a disadvantageous manner in regardto his shooting skill.

Moreover, it is less expensive to procure exchangeable barrels merely for various calibers than it is to procure entirely new repeater rifles. The characterizing tightening connection between the receiver and the barrel is also tight enough to be able to safely absorb the loads or stresses occurring during the cartridge detonation, including the vibrations which substantially influence performance.

It has, therefore, become possible to produce a quickly and simply exchangeable barrel while maintaining a freely vibrating attachment mode.

To this must be added, moreover, that the forces produced by the tightening will create a negative pretension or compression at the breech end of the barrel, that is in the cartridge chamber. This negative pre-tension acts counter to the forces occurring during the development of the shot, i.e., cartridge detonation. Therefore, the outside dimensions of a repeater gun of the type according to the invention, need not be any larger than those of known repeater guns. The firearm thus remains light and handy just like traditional firearms.

Preferably in the lower section of the longitudinal receiver flange slit, removed from the barrel recess or socket, there is a support acting as a counter support for the flange tightening elements. According to one embodiment, presented by way of example, this support or restraining means may be constituted by a screw connecting the stock with a receiver flange, which screw is screwed into a thread in the longitudinal slit. This restraining means, however, can also be a T- shaped sliding block into which the screw connecting the stock with the support has been screwed. In this case, the sliding block pulls the support onto the stock.

In the case of this embodiment, by way of example, it will be advantageous to provide a recess or blind hole in the barrel, on the periphery of the cylindricalend of the barrel which is inserted into the receiver flange. A cylindrical peg is inserted into this recess and a recess passing through the longitudinal slit. This peg is supported on a carrying surface of the sliding block. This results in the barrel being secured in axial and peripheral directions although it is also held by the tightening.

Moreover, the cylindrical peg makes certain that the barrel will always be inserted in the same position in which it had been fitted into the firearm.

The purpose of these different supports in the lower section of the longitudinal slit is to avoid bending, or barrel flattening, forces during the tightening of the tightening elements, so that merely tangential forces will engage in the barrel at the place of tightening.

Instead of securing the barrel by way of a loose cylindrical peg and a slidable sliding block, it is also possible to provide a kind of bayonet lock between the barrel and receiver flange, including locking studs at the rear end of the barrel and corresponding counter bearings or lugs at the base of the recess of the receiver flange. With this construction, a positioning of the barrel which will always be the same upon barrel insertion can be guaranteed.

Another possible mode of attachment is by way of a thread, knownper se, at the end of the barrel and in the recess of the receiver flange. However, this threaded joint does not need to be made as difficult as most threads to operate because of the longitudinal slit and the tightening elements. In order to achieve a firm selflocking seat and, as a guarantee of the exact position of the barrel after each barrel exchange process, the tightening elements, developed as fitted bolts, tangentially intersect the threaded joint. Thus, the barrel will be additionally prevented from twisting.

A particularly favorable embodiment, by way of example, which permits the exchange of the barrel without the assistance of any kind of tool, has a front part of the stock separate from the main stock. This fore-part can be flipped down by means of a tightening lever. The receiver flange constricting means of the tightening lever is constituted by cam surfaces which are provided on the mounting eyes of the tightening lever. These cam surfaces act upon corresponding cam follower surfaces of the clamping sleeves, which follower surfaces are shiftable axially on means rotatably supporting the lever so as to induce convergance of sides of the receiver flange slit. At the same time and in order to avoid asymmetry, the tightening lever effectively will be arranged symmetrical in relation to the axis of the gun.

The lever supporting means may comprise a bolt provided on both sides with knobs. On the shaft of .this bolt, the bearing eyes of the clamping lever are guided. These bearing eyes are supported by the knobs of the bolts. The clamping sleeves are inserted on the bolt between the cam means of the bearing eyes of the clamping lever and the sides of the flange slit.

In this case, the cam or ramp surfaces may be oppositely oriented threads or helical surfaces, whereby the tightened socket receiving barrel will be loosened by flipping or pivoting down the front part of the stock. After release of an additional safety, the barrel can be pulled out of the socket in a forward direction.

DRAWINGS The invention is to be explained once more in detail on the basis of the embodiments given by way of example, so that from it all the details, advantages and characteristics of the invention will become clear.

FIG. 1 shows a first embodiment of the place of con-' nection between the exchanged barrel and the receiver of the gun according to the invention by way of example in the form of a longitudinal section;

FIG. 2 shows a section following line IIII in FIG. 1;

FIG. 3 shows a second embodiment with another type of attachment of the barrel likewise in longitudinal section;

FIG. 4 shows a section according to line IV-IV in FIG. 3;

FIG. 5 is a presentation in longitudinal section of a third embodiment of the gun according to the invention by way of example;

FIG. 6 shows a section following line VIVI in FIG.

F IG. 7 shows a presentation in longitudinal section of a fourth embodiment of the gun according to the invention by way of example, with a pivotable front stock;

DETAILED DESCRIPTION The receiver 10 with breech bolt 11, firing pin 12 and firing pin spring 13, as well as the exchangeable barrel 14, is common to all embodiments given by way of example. All other parts of the firearm which have no influence on the invention and on which the invention does not exert any influence either, have been omitted for the sake of simplicity. The inside of the barrel has been made in the customary manner with a cartridge chamber 15 and a bore 16. All embodiments have, in common, a slotted support disposed underneath an annularly developed receiver flange.

The support slit has the purpose of tightening the receiver flange, in response to the action of tightening elements which narrow the slit, so that the end of barrel 14 introduced into the bore of the receiver flange will be firmly tightened but can be easily pulled out whenever the tightening elements are released. The axial and circumferential dimensions of the tightening or constrictable connection between the end of the barrel and the bore of the receiver flange are selected such that the tightening or constricting forces are large enough to absorb the axial forces occurring as a result of the strain from a shot, without any additional locking being required between the barrel and the receiver.

First of all, we shall now describe the embodiment according to FIGS. 1 and 2 presented by way of example.

The smooth cylindrical bore 21 of the receiver flange 20 has been harmonized with a recessed end 22 of the barrel in such a way that in the case of the receiver flange, when not tightened, provides a telescoping, gliding fit seat for barred end 22. Upon insertion of end 22 of the barrel into bore 21 of the receiver flange, the abutment collar 23 on the barrel strikes against the front edge of the receiver flange, before the end of the barrel itself reaches the base of bore 21.

The barrel inserted this way into the receiver flange 20 is tightened with the help of tightening

screws

24, 25. These screws lie with their heads sunk in corresponding bores of stop or flange 26. By way of their threaded shafts, these screws are screwed into corresponding female threads 27 in the half of flange 26,

which is opposite the screw head. The support itself, as

mentioned previously, has been divided into two parts by a longitudinal slit 28, which is aligned with the central axis of the barrel end receiving bore of generally cylindrical means 20. By the proper tightening of

screws

24 and 25, the clamping force of the receiver flange on the end of the barrel can be made so great that the barrel will be seated completely firmly in the receiver and the connection can absorb all axial forces occurring upon detonation of a cartridge.

In order to avoid the imposition of bending or travel flattening forces on the receiver flange 20 as a result of the screw tightening, there is a threaded bore 29 formed symmetrically in each half of clamping flange -means 26, and passing upwardly through slot 28. A

screw 30 is screwed into the lowest part of the slit via bore 29 and thus partially into the side walls of the two halves of the support 26, with which screw the receiver is screwed to the stock. With the support provided by screw or restraining means 30, which will prevent a compression of the slit by the tightening screws 24 and 25, one will perceive that, in fact, only tangential forces are imposed on barrel end 22 during tightening between the receiver flange 20 and the end 22 of the barrel.

Even though the clamping forces of

screws

24 and 25 will suffice to hold the barrel 14 in the receiver 10, an axial safety will be provided which becomes effective when, in actual fact, the tightening mechanism has not been properly tightened. Accordingly, there are circumferentially spaced lock studs 31 distributed over the periphery of the end of the barrel which are rotatable to a position behind corresponding projections 32 close to the base of bore 21. Thus, the barrel, first of all, will be inserted in socket 20, twisted counter to its final position. It will then be turned or twisted to its position of use, whereby lock studs 31 move behind projections 32. In order to assure an unequivocal position of the barrel after its rotation, a stop screw 33 has been provided. This screw enters socket 20 from the outside and projects into the path of the lock studs. Thus, upon twisting the barrel in FIG. 2 in a clockwise direction, and up to the stop 33, the barrel will then obtain its correct position in relation to the receiver.

The embodiment according to FIGS. 3 and 4 show generally a similar construction.

In this embodiment the offset (i.e., reduced) end 42 of the barrel is likewise inserted into a receiver flange 40 up to the extent permitted by engagement of a barrel abutment 43 with the end of the socket 40, while tightening

elements

44, 45 of the bipartite stop 46 are loosened. In this case, also, a screw 50, serving for the attachment of the receiver to the stock of the gun, engages with female threaded sides of slit 48 in order to exclude any barrel bending or flattening forces during flange tightening.

In the present case, however, the prevention of axial movement between the end 42 of the barrel and the receiver flange 40 is accomplished by way of a threaded connection 41 However, and in contrast to the known connections, and with loosened tightening

screws

44, 45, the barrel can easily be screwed into the receiver flange 40.

As a matter of safety, and for the purpose of an unequivocal fixation of the barrel in the receiver, the transverse bores for the tightening screws 44 and 45 have been disposed in such a manner that the screws, which have been developed partly with a cylindrical shaft 51, intersect concave, cylindrical segment recesses formed to extend transversely of the connecting thread 41. As a result of this, the tightening screws 44, 45 can be inserted and tightened only when the barrel has been screwed into a quite definite axial position, namely the stop position, and into a quite definite angular position, so as to align the thread recesses of barrel 1 4 with the bores for

screws

44, 45. Thus, even in the case of loosening of the tightening screws 44 and 45, the barrel still cannot be separated from the receiver due to the intersection of

screws

44, 45 with the transverse recesses of thread means 41.

A development similar to the one in the first design is shown by the example according to FIGS. 5 and 6.

Here too there is a receiver flange 60 with a smooth inside bore 61. In this bore, an end 62 of the barrel 14 is inserted up to the abutment of its collar 63 with the front edge of the receiver flange 60.

A stop or flange means is provided with a longitudinal, vertical slit 68 and includes transverse bores for the reception of tightening

screws

64 and 65. These screws are disposed approximately in the same position as in the example according to FIGS. 1 and 2.

The safety, and axial as well as angular fixation of the barrel in the receiver flange is accomplished in this case in a different manner.

As FIG. 6 shows, the vertical flange means slit, in its lower section, has a T-shaped enlargement 71 in which there is a longitudinally slidable sliding block 72. This sliding block 72 serves, for one thing, the purpose of preventing the excessive compression of slit 68 by the tightening screws, so that only tangential forces can be imposed on the circumference of the barrel due to the screw induced constriction of socket means 60. The sliding block is fixed in an axial direction by means of attaching screw means 79, with which the receiver is screwed onto the gun stock.

Prior to tightening of the tightening screws 64, 65 and the insertion of attaching screw 70, however, the restraining means or sliding block is slidable in an axial direction in its T-shaped slit. This permits a cylindrical pin 73 or alignment recurring means to be slipped in, from below through second aligning recess means or fitted bore in the flange means, into engagement with a correspondingly fitted first aligning recess means or blind hole 74 in the cylindrical end of the barrel, and thus fix the barrel both axially and in its angular position. With cylindrical pin 73 completely inserted, the sliding block 72, with its offset end or restraining means 75, can be pushed along slit 71 to dispose its offset end below the cylindrical pin so that the latter can no longer glide out of its fitted bore means. The axial fixation of sliding block 72 is then accomplished by means of attaching screw being screwed into engagement with the portions of flange means 66 above block 72.

Thus the barrel has been exactly aligned in the receiver and, moreover in the case of a possible loosening of the tightening screws 64 and 65, it has been secured from dropping out.

Another solution again is in FIGS. 7 and 8.

End 82 of the barrel and receiver flange 80, inclusive of the arrangement of the lock studs 91 and counter elements or projections 92 in the bore, are the same as the corresponding elements in the example described on the basis of FIGS. 1 and 2. The support 66 too is provided with a vertical, longitudinal slit 88, which has in its lower portion, a T-shaped enlargement 93, as known already from the embodiment according to FIG. 5. Slot enlargement 93 receives a sliding block 94, into which a screw 95 is threadably disposed for the attachment of the stock and securing of block 94.

In this case too, sliding block 94 serves to avoid the occurrence of bending or barrel flattening forces during tightening of the receiver flange. The tightening of the receiver flange, however, in the case of the embodiment described here, is accomplished in a particularly simple manner and is particularly practical for operation during exchange of the barrel.

A cylindrical tightening bolt 97, provided with heads 96, passes through a bore of support 86. A tightening lever 98, pointing longitudinally forward, has been mounted with bearing eyes 99 joumaled on the tightening bolt 97.

shown by the embodiment Discs 100 have been provided, each of which is rotatably slidably supported on one side by a bolt head 96 and on the other side has a screw-shaped ramp surface. A transverse bore 101 in the support 86 has been provided with a frusto-conical enlargement on both entry ends. Clamping sleeves 102 fit in these enlargements and have screw-shaped or helical cam follower surfaces corresponding to the shapes of cam surfaces of the annular discs 100.

The annular discs 100 are rigidly connected with the bearing eyes 99 of the tightening lever. The effective distance between the outer surfaces of the clamping sleeves 102, acted on by discs 100, becomes smaller or larger depending on the position of the lever upon pivoting of the clamping lever 98. The ramp surfaces are dimensionally harmonized in such a way with regard to one another that, in the case of being swung upwards, the effective distance between the sides of the receiver as defined by sleeves 102 is the smallest and, as a result of that, the support is clamped together. The distance becomes larger when the lever 98 is pivoted downwards. At the same time, of course, the clamping connection between the receiver flange 80 and end 82 of the barrel is loosened.

in this embodiment the fore-stock of the gun is subdivided into the fixed part 103 and a front part 104 that can be let down. Part 1041 is connected by means of an attaching screw 105 with the clamping lever 98. However, there is no connectin between the front part of the stock and the barrel.

The operation, in the case of exchanging barrels, is as follows.

The front part 104 of stock is pivoted or swung down, together with clamping lever 98. During this time, annular discs 100 are rotated in relation to the clamping sleeves 102 and the clamping force exerted on these sleeves and transmitted to the support declines. Now the barrel can be twisted from its

bayonet lock

91, 92 and can be pulled out from the cylindrical bore of the receiver flange 80. After insertion of another barrel, with for example a different caliber, which is put into the inserting positon with the same bayonet catch, the front part of stock 104 may be pushed up again. As a result, the clamping sleeves 102 are again compressed by the camming cooperation between

elements

100 and 102 and a clamping force is exerted by the support on receiver flange 80. Therefore, with this embodiment, it is particularly easy to carry out an exchange of the barrel.

To this advantageous development which makes possible a particularly quick and simple exchange of the gun barrels, it must be added that, as a result of the negative pre-tension or compression exerted by the clamping forces of the receiver flange at the end of the barrel, there will be a relieving counter effect operable to offset the radial forces occurring during firing of the shot. Thus, it will not be necessary to construct the entire arrangement, for reasons of strength, with more expensive material than that which is used in the case of known guns with exchangeable barrels.

SUMMARY OF MAJOR ADVANTAGES AND GENERAL SCOPE OF INVENTION A principal advantage of the invention resides in the provision of a uniquely simplified barrel clamping arrangement which facilitates barrel exchange and minimizes or eliminates the necessity for repeated zeroing-in.

Another advantage of the invention relates to the particular circumferential clamping arrangement which is operable to impose tangentially directed barrel end securing forces, without inducing barrel flattening or distortion.

The embodiment of the apparatus which is characterized by a lever actuated clamping device provides a uniquely simplified and reliable arrangement permitting an exchange of gun barrels without requiring recourse to special tools or equipment or an increase in size or weight of gun components.

Those familiar with this disclosure and skilled in the firearms art may recognize additions, deletions, substitutions or modifications which would fall within the purview of the invention as set forth in the appended claims.

What is claimed is:

1. A firearm including exchangeable barrel means and comprising:

receiver flange means including barrel receiving socket means for receiving a terminal end portion of said barrel means,

support means disposed generally beneath said socket means, and

longitudinal slit means formed in said support means and operable to permit circumferential contraction of said barrel receiving socket means;

said support means being operable to be connected with firearm stock means; and clamping means carried by said support means and operable to engage said flange means on opposite sides of said slit means, induce convergence of said opposite sides of said slit means, and cause circumferential contraction of said barrel receiving socket means of said flange means. 2. A firearm as described in claim 1 further including:

restraining means engaging outermost portions of said opposite sides of said slit means, said restraining means being operable to restrain convergence of said outermost portions of said opposite sides of said slit means and thereby cause said clamping means to induce convergence of inner portions of said sides of said slit means so as to produce circumferential contraction of said barrel receiving socket means without imposing substantial barrel flattening forces on barrel means received in said socket means. 3. A firearm as described in claim 2 wherein: said restraining means comprises connecting means operable to interconnect said support means with a firearm stock means; and

said restraining means further comprises screw means threadably engaging said opposite sides of said slit means, with said screw means extending along an axis which is generally perpendicular to a longitudinal axis of said barrel means.

4. A firearm as described in claim 2 wherein:

said slit means has a generally T-shaped cross sectional configuration, extending transversely of the longitudinal axis of said barrel means; and said restraining means comprises:

block means having a generally T-shaped cross section slidably disposed in said slit means for sliding movement longitudinally of said barrel means, and threaded securing means threadably mounted in said block means and operable to abuttingly engage generally downwardly facing surfaces of said slit means. 5. A firearm as described in claim 1 further including:

first, aligning recess means formed on the outer periphery of said barrel means; second, aligning recess means formed in said support means; alignment securing means operable to extend through each of said first and second recess means and thereby secure said barrel means in a predetermined position relative to said flange means; block means slidably carried by said support means;

and restraining means carried by said block means and operable to abuttingly engage and secure said alignment securing means in said first and second recess means. 6. A firearm as described in claim 1 further comprising:

bayonet-type locking lug means detachably interconnecting said barrel means and said flange means; and

stop means carried by said flange means and operable to maintain said bayonet-type locking lug means in a barrel means securing position. 7. A firearm as described in claim 1 further comprismg:

first threaded surface means carried by said flange means; and second threaded surface means carried by said barrel means and operable to threadably engage said first threaded surface means; said clamping means being operable to intersect said threadably engaged first and second threaded surface means and thereby maintain said first and second threaded surface means in a predetermined axial relationship.

8. A firearm as described in claim 1 wherein said clamping means comprises:

lever means pivotally connected with said receiver flange means;

rotary cam means carried by said lever means; and

cam follower means carried by constrictable portions of said support means disposed laterally adjacent said slit means;

said cam means of said lever means being operable to cammingly cooperate with said cam follower means to induce barrel means clamping constriction of said barrel receiving socket means in response to pivotal movement of said lever means toward said barrel means.

9. A firearm as described in claim 8 wherein:

said lever means comprises:

mounting eyes disposed on opposite lateral sides of said support means; said clamping means comprises bolt means transversely intersecting said slit means and providing rotatable support for said eye means; and

said rotary cam means comprises a pair of rotary cams each supported by one of said eye means.

10. A firearm as described in claim 9 wherein said rotary cam means comprises a pair of generally helical cam surface means disposed on opposite sides of said support means and generally facing said slit means.

1 l. A firearm as described in claim 10 wherein:

said slit means has a generally T-shaped cross sectional configuration, extending transversely of the longitudinal axis of said barrel means; and

restraining means being carried by said support means and comprising:

block means having a generally T-shaped cross section slidably disposed in said slit means for sliding movement longitudinally of said barrel means, and

threaded securing means threadably mounted in said block means and operable to abuttingly engage generally downwardly facing surfaces of said slit means.

l2.-A firearm according to claim 1 wherein said receiver flange means further includes:

means, in addition to said clamping means, for resisting axial displacement of said barrel means from said socket means.

Claims

1. A firearm including exchangeable barrel means and comprising: receiver flange means including barrel receiving socket means for receiving a terminal end portion of said barrel means, support means disposed generally beneath said socket means, and longitudinal slit means formed in said support means and operable to permit circumferential contraction of said barrel receiving socket means; said support means being operable to be connected with firearm stock means; and clamping means carried by said support means and operable to engage said flange means on opposite sides of said slit means, induce convergence of said opposite sides of said slit means, and cause circumferential contraction of said barrel receiving socket means of said flange means.

2. A firearm as described in claim 1 further including: restraining means engaging outermost portions of said opposite sides of said slit means, said restraining means being operable to restrain convergence of said outermost portions of said opposite sides of said slit means and thereby cause said clamping means to induce convergence of inner portions of said sides of said slit means so as to produce circumferential contraction of said barrel receiving socket means without imposing substantial barrel flattening forces on barrel means received in said socket means.

3. A firearm as described in claim 2 wherein: said restraining means comprises connecting means operable to interconnect said support means with a firearm stock means; and said restraining means further comprises screw means threadably engaging said opposite sides of said slit means, with said screw means extending along an axis which is generally perpendicular to a longitudinal axis of said barrel means.

4. A firearm as described in claim 2 wherein: said slit means has a generally T-shaped cross sectional configuration, extending transversely of the longitudinal axis of said barrel means; and said restraining means comprises: block means having a generally T-shaped cross section slidably disposed in said slit means for sliding movement longitudinally of said barrel means, and threaded securing means threadably mounted in said block means and operable to abuttingly engage generally downwardly facing surfaces of said slit means.

5. A firearm as described in claim 1 further including: first, aligning recess means formed on the outer periphery of said barrel means; second, aligning recess means formed in said support means; alignment securing means operable to extend through each of said first and second recess means and thereby secure said barrel means in a predetermined position relative to said flange means; block means slidably carried by said support means; and restraining means carried by said block means and operable to abuttingly engage and secure said alignment securing means in said first and second recess means.

6. A firearm as described in claim 1 further comprising: bayonet-type locking lug means detachably interconnecting said barrel means and said Flange means; and stop means carried by said flange means and operable to maintain said bayonet-type locking lug means in a barrel means securing position.

7. A firearm as described in claim 1 further comprising: first threaded surface means carried by said flange means; and second threaded surface means carried by said barrel means and operable to threadably engage said first threaded surface means; said clamping means being operable to intersect said threadably engaged first and second threaded surface means and thereby maintain said first and second threaded surface means in a predetermined axial relationship.

8. A firearm as described in claim 1 wherein said clamping means comprises: lever means pivotally connected with said receiver flange means; rotary cam means carried by said lever means; and cam follower means carried by constrictable portions of said support means disposed laterally adjacent said slit means; said cam means of said lever means being operable to cammingly cooperate with said cam follower means to induce barrel means clamping constriction of said barrel receiving socket means in response to pivotal movement of said lever means toward said barrel means.

9. A firearm as described in claim 8 wherein: said lever means comprises: mounting eyes disposed on opposite lateral sides of said support means; said clamping means comprises bolt means transversely intersecting said slit means and providing rotatable support for said eye means; and said rotary cam means comprises a pair of rotary cams each supported by one of said eye means.

11. A firearm as described in claim 10 wherein: said slit means has a generally T-shaped cross sectional configuration, extending transversely of the longitudinal axis of said barrel means; and restraining means being carried by said support means and comprising: block means having a generally T-shaped cross section slidably disposed in said slit means for sliding movement longitudinally of said barrel means, and threaded securing means threadably mounted in said block means and operable to abuttingly engage generally downwardly facing surfaces of said slit means.

12. A firearm according to claim 1 wherein said receiver flange means further includes: means, in addition to said clamping means, for resisting axial displacement of said barrel means from said socket means.