Device for mounting a gun barrel on a firearm
United States Patent Keppeler Apr. 15, 1975 [54] DEVICE FOR MOUNTING A GUN BARREL 2,216,022 9/1940 Pomeroy 42/75 B O A FIREARM 3,027,672 4/1962 Sullivan 42/76 A 3,386,336 6/1968 Roy 42/75 B [75] Inventor: Dieter Keppeler, Ulm, Danube,  
 Germany Przmary Exammer-Stephen C. Bentley Assigneel Carl Walther pfi Attorney, Agent, or Firm-Edmund M; Jaskiewicz,  
 Ulm, Danube, Germany [22] F11ed. Nov. 16, 1972 ABSTRACT [21] App1. No.1 307,014  
  A gun barre1 has a locking bushing threaded on its rearward end and secured in position and the barrel [3O] Forelgn Apphcauo Pmmty Data end together with the locking bushing is inserted into Nov. 19, 1971 Germany 2157420 a breech casing such that the locking bushing positions the end of the gun barrel within the casing. A [52] US. Cl 42/75 B second bushing is carried on the gun barrel and is [51] Int. Cl. F41C 21/00 threaded within the breech casing to remov ably [53] Field of Search 89/ cure the gun barrel within the breech casing. The gun 42/75 76 R, 76 7 barrel is maintained in a proper relationship within the breech casing by a pin within the breech casing re- [56] References Cited ceived within a groove in the locking bushing.  
  UNITED STATES PATENTS 1 D g 2,139,648 12/1938 Chambers 42/16 2 Clams raw&#39;ng F&#39;gure PATENTEU APR 1 5|H75 DEVICE FOR MOUNTING A GUN BARREL ON A FIREARM The present invention relates to firearms including automatic weapons, more particularly. to the removeable mounting of a gun barrel on the breech casing of such weapons.  
  Various structures and assemblies are known for mounting a gun barrel in such a manner that the gun barrel can be replaced. In one such arrangement threads are provided around the cartridge chamber end of the barrel to enable the barrel to be threaded into the breech chamber to abut against suitable structure therein and also to enable removal and replacement of the barrel.  
  Another known structure enables a gun barrel to be threaded into the breech casing by means of threads arranged on a pin-like extension and a locking ring positioned on the same threads. The ring is rotated so as to press the breech against the rear face of the end of the gun barrel.  
  It has also been proposed that a locking bushing is inserted into the breech casing and secured therein against turning and locking the bolt handle. The rear face of the bushing presses against the breech casing and its front face acts as an abutment for the rear end of the barrel which is threaded into the breech casing. For example, reference is made to French Pat. Nos. 419,869 and 467,967 and the U.S. Pat. No. 2.139.648.  
  All of the above mentioned structures for mounting a gun barrel are characterized by having the same great disadvantage, namely the relatively high cost of manufacturing the several components involved. As a result. the replacement of a gun barrel becomes a complex and time-consuming operation. In addition. a replaced barrel must be readjusted and test-fired after the replacement before the weapon can be placed in use.  
  It is therefore the principal object of the present in vention to provide a novel and improved device for the replaceable mounting of a gun barrel in a firearm.  
  It is another object of the present invention to provide a simple and relatively inexpensive structure which makes it possible to quickly replace the barrel of a firearm with a minimum of effort and without the necessity of subjecting the weapon again to test-firing.  
  The disadvantages of the prior art as described above are eliminated and the objects of the present invention are achieved by the present invention. According to one aspect of the present invention a firearm and particularly an automatic weapon has a gun barrel with a locking bushing secured on its rearward end. The rearward end of the barrel together with the locking bushing is inserted into a breach casing. The locking bushing positions the rearward end of the barrel within the breech casing. A threaded bushing is carried on the barrel and is threadedly engageable with the breech casing when the rear end of the barrel is inserted into the breech casing. The threaded bushing removeably secures the gun barrel and within the breech casing so that the gun barrel is exchangeable or replaceable by a different caliber barrel in the same firearm without any change in the relationship between the gun barrel and breech.  
  Other objects and advantages of the present invention will be apparent upon reference to the accompanying description when taken in conjunction with the following drawing, which is exemplary, wherein there is illustrated a partial longitudinal sectional view through a breech casing and rearward end of the barrel .ment of the present invention will be described in detail.  
  The rearward end ofa gun barrel is indicated at l and hasan external thread 2 on the extreme end thereof upon which is-threaded a locking bushing 3. The bushing and threads surround the cartridge chamber 1&#39; in the end of the barrel. During the manufacture and assembly of the firearm at the factory. the bushing J is threaded onto the barrel to such a point that the distance between the cartridge chamber end of the barrel and the breech projection bearing surfaces 4 of the bushing 3 correspond to a standard established by the industry and by governmental agencies. This distance is indicated at l&#34;. The bushing 3 is secured in its threaded position on the barrel 1 by means of a weld. solder or a suitable adhesive. The breech projection bearing surfaces on the bushing 3 are formed by means of recesses as known in the art.  
  The bushing 3 is provided with an external groove or notch 7 which receives a pin 9 firmly secured within the breech casing when the cartridge chamber end of the barrel is inserted into the breech casing indicated at 8. The pin 9 thus positions the barrel 1 and bushing 3 into the correct position with respect to breech block 6 having breech projections 5 and also secures the barrel and bushing assembly against any rotary movement with respect to the breech block.  
  A second bushing 10 having external threads 10&#39; is slideably carried upon the barrel 1 and is threaded into suitable internal threads provided within the breech casing 8. The bushing 10 urges the barrel 1 by means of the bushing 3 against an abutment 11 within the breech casing to fix the position of the barrel with respect to the breech casing.  
  In order to remove the barrel 1 and bushing 3 from the breech it is merely necessary to unthread the bushing 10 and the barrel and bushing assembly can be removed from the breech casing and replaced by a new barrel and bushing of the same or a different caliber. After the new barrel has been replaced into the breech casing a weapon is immediately ready for firing without any necessity for test-firing since the barrel has been correctly positioned with respect to the breech.  
  The quick and precise interchanging of barrels of different calibers is particularly useful in hunting since this feature enables the hunter to use the same weapon to shoot at various types of game. For example, a smaller caliber barrel would be used for small game. such as rabbits than for larger animals, such as deer. in a matter of seconds the hunter can replace a gun barrel in the field without the use of tools.  
  It is therefore apparent that the present invention has disclosed a-structure or device by which it is possible to insert new barrels of the same or different caliber into the same weapons without any changes to the breech distance and without any necessity for readjustment or test-firing of the new barrel. A further advantage of the present invention is that certain manufacturing tolerances may be disregarded since these tolerances can be compensated by the adjustable features of the present invention.  
  it will be understood that this invention is susceptible to modification in order to adapt it to different usages and conditions. and accordingly. it is desired to comprehend such modifications within this invention as may fall within the scope of the appended claims.  
 What is claimed is:  
  1. In a firearm and particularly repeating guns. the combination of a gun barrel having a locking bushing threaded on its rearward end and axially adjustable thereon, and a second threaded bushing on said barrel threadedly engageable with a breech casing and in abutting engagement with the forward end of said locking bushing when the rear end of the barrel is inserted into said breech casing to removably secure the gun barrel within the breech casing, a breech block secured within said breech casing. said locking bushing being secured on the rear end of the barrel in a position corresponding to a predetermined standard distance betiveen the rear end of the barrel and the forward end of said breech block so that the gun barrel is exchangeable or replaceable by a same or different caliber barrel in the same firearm without any change in the relationship between the gun barrel and breech.  
  2. In a firearm as claimed in claim 1, wherein said locking bushing has a groove therein, and a pin within said breech casing and positionable within said groove to locate the barrel and locking bushing in proper relationship within said breech casing and to prevent rotary movement of said barrel and locking bushing with respect to said breech casing.