Abstract:
A removable inner barrel apparatus has a rifle with barrel extending therefrom, an inner barrel having an end through which ammunition can exit, a pressure nut removably fastening the barrel of the rifle to the inner barrel, and a compression spring positioned within the pressure nut. The inner barrel has a grooved hollow interior and a bushing affixed adjacent to an opposite end thereof. The compression spring urges against a surface of the bushing so as to urge the bushing against the end of the inner barrel.

Description:
RELATED U.S. APPLICATIONS 
     Not applicable. 
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     REFERENCE TO MICROFICHE APPENDIX 
     Not applicable. 
     FIELD OF THE INVENTION 
     The present invention refers to a novel inner barrel for sport rifles, which has the particularity to be installed or removed in a simple way and allows the use of ammunition or pellets of different calibers. 
     In this way, the sport rifle becomes a versatile device that uses indifferently either ammunition or pellets of different calibers without the necessity of removing the barrel. On the other hand, this inner barrel can be adapted in sport rifles carrying out, previously, a simple repair consisted in making a cord on the mouth of the barrel and increasing the correlative diameter to the proposed inner barrel, in order to become a versatile rifle. 
     This novel invention has to be installed in the interior of the original barrel of the sport rifle, introducing enough of the proposed barrel by the end of the original barrel, where the sight point is normally located. The adjustment and bond of the proposed barrel is made by means of an external nut, which is tightened manually, with no need of any tool, in order to be able to shoot the weapon immediately. 
     BACKGROUND OF THE INVENTION 
     The development of the versatility of barrels change for conventional rifles and non-sport ones, has been discussed and made accessible in many ways such as the special barrels interchange which are made in a special way, which exceed from the discussed considerations in this work. 
     The proposed invention has the characteristic of using the same original barrel of the sport weapon and introducing inside this, a removable inner barrel according to the desired caliber, so the sport rifle is accompanied of various removable inner barrels depending on the caliber to be used. 
     Besides, the proposed invention can adapt to already existing sport rifles by means of a very simple repair. 
     Dealing with sport air rifles, operated by springs or by gas, it has not been considered, and consequently according to the author&#39;s best knowledge of the proposed invention, there are no registered or published records. 
     BRIEF SUMMARY OF THE INVENTION 
     The present invention is used as a sport and diversion article, where different calibers of ammunition or pellets can be used with only inner barrels substitution. 
     This has a fundamental economic advantage, because one can shoot either ammunition or pellets with a high-speed exit and a minor exit impact force or vice versa, without the need to acquire sport rifles of many calibers. Accordingly, the present invention has its reach inside the sport air rifles universe operated with springs or by means of gas either for ammunition or for pellets. 
     It is one aim of the present invention, to use indifferently different types of calibers for ammunition or pellets for sport rifles. 
     It is another aim of this invention, to count with different types of removable inner barrels to be placed inside the barrel of a sport rifle in a simple way and without using any tools. 
     It is another aim of the present invention to eliminate the cylindrical formed packing in the original barrel of the sport rifle, precisely in the place where the ammunition of the pellets are placed, because the proposed invention includes a shove mechanism in the inner barrel against the plate of the caisson of the weapon mechanism, whose longitudinal movement avoids the leak of pressure. 
     The characteristic details of this adaptable inner barrel in the interior of the original barrel of ammunition or pellets sport rifles, are clearly shown in the next description and in the drawings attached, as an illustration of such, and the same reference signs used to indicate the same parts in the shown figures. 
    
    
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     FIG. 1 is a side view of the original barrel for a sport rifle. 
     FIG. 2 is a side view of the original barrel of a sport rifle with part of the proposed invention. 
     FIG. 3 is a sectional view of the removable inner barrel. 
     FIG. 4 is a sectional view of the barrel of the sport rifle combined with the removable inner barrel. 
     FIG. 5 is a perspective view of the removable inner barrel. 
     FIG. 6 is a front view of the pressure nut. 
     FIG. 7 is another left side view of the union nut. 
     FIG. 8 is a sectional view of the pressure nut. 
     FIG. 9 is a sectional view of the compression spring. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The present invention, refers to a removable inner barrel for ammunition or pellets for sport rifles, by means of which a safe rifle operation is guaranteed, free from causing any accident and useful to be used with different calibers of ammunition by means of a simple change of the removable inner barrel. 
     In reference to the mentioned figures, the present invention, consists of a sport rifle with a butt as support for the shooting with a caisson of the mechanism precisely where the parts of a shooting mechanism of the weapon are located and by a barrel, an original barrel  10  of the rifle, in the front part, where the shooting or shot of the ammunition will exit. 
     This original barrel  10  of the rifle, comprehends in its frontal end, towards the exit where the shot will come out, an external thread  12 , as a fixing element, followed by a top ring  14 , located before the sight point  16 , of the weapon, consisting in an annular string or fixed jacket, whose purpose is to serve as top for the closing up, meanwhile the interior part of the original barrel  10  of the rifle, is prepared for the polished wall and without special grooving. 
     A removable inner barrel  20 , located by a tube with a diameter correlative to the interior diameter of the original barrel  10  of the rifle, inside it is hollow and grooved, where the interior diameter is correlative to the ammunition or pellet caliber. This removable inner barrel  20 , presents in its superior extremity a bushing  22 , united to the same body of the removable barrel  20 , with the same diameter of the external diameter of the original barrel  10  of the rifle, so when the removable inner barrel is introduced inside this it will stop, coming out from the extremity part of such inner barrel  20 , a part or section lightly short which is called projecting terminal  24 , at the extremity where the ammunition or pellet is introduced. A pressure nut  30  is formed of a cylindrical piece, with grooves (knurled)  36 , by its exterior face whose function will be to serve as a supporting element, and its drilled interior, carrying on one end an orifice  32  bigger in diameter compared to the exterior diameter of the barrel  10 , for its introduction in it, besides an interior thread  34 , correlative to the thread  12 , with which the pressure nut  30  will stay fixed until the moment of arriving to the top  14 . 
     A compression spring  40 , which stays at the end of the orifice  32 , whose function is to serve as a damping element and at the same time, to ensure an appropriate airtightness between the interior barrel  20  and the weapon mechanism, the spring left pressed  40  against the frontal wall of the bushing  22 , and at the same time such a push is transmitted up to the end of the inner barrel  10 , causing the end of the projecting terminal just out slightly  24 , which is the place where the ammunition or pellet will be introduced, exactly in front of where the caisson of the weapon mechanism is located and an air expansion will be produced with the characteristic that by means of this spring, compressed air leakage is avoided. 
     On the other hand, orifice  32 , is coincident with the bushing diameter  22 , and remains transversally grasped together with the removable inner barrel  20  but with a longitudinal movement derived from the spring damping effort  40 , whose stroke or play, corresponds to the length that projects at the end of the projecting terminal  24  of the removable inner barrel  20 . 
     Finally, the orifice  32 , diminishes its diameter up to the correlative exterior diameter of the removable inner barrel  20 , to stick out the end of that by the pressure nut  30 . 
     Each rifle will come with several inner tubes  20  properly identified by the caliber of the ammunition in order to avoid mistakes. 
     Inasmuch as the way to operate all the mechanism mentioned before, it is very simple, because it will be sufficient to insert in the original barrel  10  of the sport rifle the inner barrel  20 , placing the spring  40 , in the inner nut  30 , in order to fasten and tighten the nut  30  by means of the external cord  12 , taking this nut  30  until this makes contact with the top ring  14 . 
     Doing this, the spring  40 , will stay loose, pushing the frontal face of the bushing  22 , and so the projecting ending  24  of the removable inner barrel  20  presents itself slightly projecting in front of the caisson of the weapon mechanism. 
     During the breaking of the rifle to load the ammunition or pellet, the terminal  24  will be projecting. An ammunition or pellet is placed, and when closing the rifle, the plate of the caisson of the mechanism, compresses the projecting terminal  24  so, then, the face of the bushing  22 , compresses the spring  40  up to its maximum position, projecting the end of the inner barrel  20 , by the minor orifice of the nut  30 . This operation of the longitudinal movement of the inner barrel  20 , repeats itself in the opposite way when breaking the rifle to be loaded. 
     Thus, for example, if it is desired to operate the rifle with higher speed exit of the ammunition or pellet, an inner barrel will be used  20  with a minor inner diameter and so the impact force will be minor, if on the contrary a major impact force is desired, an inner barrel is placed  20  with an inner major diameter, and so the exit speed of the projectile diminishes. 
     In this way, in order to use different calibers of ammunition and pellets, the only thing required is to change the different types of inner barrels  20 , using the same rifle.