Abstract:
An auto-loading firearm may obtain improved firing precision by using stored energy to cycle the firearm. The firearm may be partially cycled when the trigger is pulled. The firearm may be completely cycled only when the trigger is released. Sound suppression and/or sound reduction may be obtained by limiting the amount of gas escaping the breech during extraction as well as separating the noise of the firing event from the noise of the action cycling.

Description:
STATEMENT OF GOVERNMENT INTEREST 
     The inventions described herein may be manufactured, used and licensed by or for the U.S. Government for U.S. Government purposes. 
    
    
     BACKGROUND OF THE INVENTION 
     The invention relates, in general, to firearms, and, in particular, to gas-operated, auto-loading firearms. 
     In auto-loading firearms, the cycle of operation is initiated by pressing the trigger. Once initiated, the entire cycle of operation is generally completed. In manually-operated firearms, on the other hand, the shooter is required to manually cycle the action of the firearm for the next round to load and be ready for firing. Manually-operated firearms are generally thought to be inherently more accurate than a similarly constructed auto-loading firearm due to the absence of recoiling parts during firing. Precision is often considered to have been traded off in favor of the convenience and speed of auto-loading. 
     Additionally, when an auto-loading firearm is fitted with a muzzle device for the purpose of suppressing the muzzle signature, there is often an increase in gas pressures and volumes that exit through the breech of the firearm during the automatic cycle of operation. These increases in gas pressure and volume at the breech can result in additional noise of the cycling of the action, and of gasses escaping through the breech. For these reasons, the manually-operated firearm is sometimes preferred over the auto-loading firearm, at the expense of the convenience of the auto-loading firearm. 
     U.S. Pat. No. 4,409,883 was issued on Oct. 18, 1983 to Edouard Nyst and is expressly incorporated by reference herein. The Nyst patent describes a rifle wherein the combustion gasses may be used to store energy in a spring and piston. When the gun user wishes the rifle&#39;s action to cycle, a latch mechanism on the forestock of the rifle may be pressed to thereby release the stored energy and cycle the rifle. The Nyst design may not be easily adapted to other weapons, such as handguns. Further, the Nyst design requires the user to operate both the trigger and a separate mechanism on the forestock. 
     SUMMARY OF THE INVENTION 
     It is an object of the invention to provide a gas-operated, auto-loading firearm wherein cycling of the firearm may be delayed and then initiated using the trigger. 
     In one aspect, a gas-operated, auto-loading firearm may include a barrel fixed to a receiver, a trigger disposed in the receiver and biased to a forward position, a bolt carrier disposed in the receiver, and a locking lever disposed between the trigger and the bolt carrier. A gas piston may be slidably disposed in a gas piston chamber. The gas piston may include a head and a rear surface having a protrusion thereon. 
     A gas bleed line may be disposed between the barrel and the gas piston chamber. A piston catch may be disposed in the receiver and may have a downward bias. A spring-loaded detent may be disposed between the piston catch and the bolt carrier. In a forward position of the bolt carrier, the spring-loaded detent may provide an upward bias to the piston catch that overcomes the downward bias. 
     A gas piston spring may be disposed between the gas piston head and a forward surface of the bolt carrier. A return spring may be disposed between the rear surface of the gas piston and a surface of the receiver. 
     In another aspect, a method may include providing a gas-operated, auto-loading firearm, activating a trigger of the firearm, compressing a gas piston spring, and then, cycling the firearm by deactivating the trigger of the firearm. 
     The invention will be better understood, and further objects, features, and advantages thereof will become more apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings, which are not necessarily to scale, like or corresponding parts are denoted by like or corresponding reference numerals. 
         FIG. 1  is a side view of an embodiment of a gas-operated, auto-loading firearm in a ready to fire position. 
         FIG. 2  is a side view of the firearm of  FIG. 1  showing the trigger manipulated just prior to firing. 
         FIG. 3  is a side view of the firearm of  FIG. 1  showing the combustion gasses acting on the gas piston. 
         FIG. 4  is a side view of the firearm of  FIG. 1  showing the gas piston locked to the rear. 
         FIG. 5  is a side view of the firearm of  FIG. 1  showing the bolt carrier released and moving rearward. 
         FIG. 6  is a side view of the firearm of  FIG. 1  showing the bolt carrier at the end of its rearward travel. 
         FIG. 7  is a side view of the firearm of  FIG. 1  showing the bolt carrier and gas piston moving forward together. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A gas-operated, auto-loading firearm may combine the convenience of an auto-loading firearm with the precision of a manually-operated firearm by using stored energy. A gas-operated, auto-loading firearm may store the energy from firing a round of ammunition and then, later, release that energy for the purpose of cycling the action of the firearm. The energy may be released as a natural function of releasing the trigger. 
     Operation of the firearm may be performed with the user&#39;s trigger finger through a normal application and release of the trigger. No additional training may be required because the operation of the firearm is naturally performed. The firearm may be a rifle, a shotgun, or a handgun. 
       FIG. 1  is a side view of an embodiment of a firearm  10  in a ready to fire position. A gas-operated, auto-loading firearm  10  may include a barrel  14  fixed to a receiver  12 . A trigger  16  may be disposed in the receiver  12 . Trigger  16  may be biased to the forward position shown in  FIG. 1  by, for example, a trigger spring  18  disposed between trigger  16  and receiver  12 . 
     A bolt carrier  20  may be disposed in the receiver  12 . Bolt carrier  20  may carry a rotating and locking bolt or other breech locking mechanism (not shown). A locking lever  22  may be caused to move by motion of trigger  16 . In the forward position of trigger  16  shown in  FIG. 1 , locking lever  22  may not prevent rearward movement of bolt carrier  20 . 
     A gas piston chamber  24  may have a gas piston  26  slidably disposed therein. A gas bleed line  28  may be disposed between barrel  14  and gas piston chamber  24 . Gas piston  26  may include a head  44  and a rear surface  30 . Rear surface  30  may include a protrusion  32  ( FIGS. 3-5 ) thereon. Protrusion  32  may prevent translation of bolt carrier  20  beyond rear surface  30  of gas piston  26 . Protrusion  32  may also translate bolt carrier  20  forward when protrusion  32  contacts bolt carrier  20  and gas piston  26  is moving forward. 
     A piston catch  34  may be disposed in receiver  12 . Piston catch  34  may be downwardly biased by, for example, piston catch spring  36 . In  FIG. 1 , piston catch  34  is in an upward position. A spring-loaded detent  38  may be disposed between piston catch  34  and bolt carrier  20 . In the forward position of bolt carrier  20  shown in  FIG. 1 , spring-loaded detent  38  may provide an upward bias to piston catch  34  that overcomes the downward bias provided by piston catch spring  36 . 
     A gas piston spring  40  may be disposed between gas piston head  44  and a forward surface  42  of bolt carrier  20 . A return spring  46  may be disposed between rear surface  30  of gas piston  26  and a surface  48  of receiver  12 . 
     In  FIG. 1 , bolt carrier  20  is closed with a round of ammunition (not shown) chambered in barrel  14 . Trigger  16  is in its forward resting position and locking lever  22  is down. Gas piston  26  is in its forward position. Bolt carrier  20  is in its forward position. As seen in  FIG. 2 , when trigger  16  is operated, locking lever  22  is raised to prevent bolt carrier  20  from moving rearward. Upon firing, the projectile moves down barrel  14 . When the projectile passes gas bleed line  28 , some portion of the propelling gasses may be bled to gas piston chamber  24 . 
     As seen in  FIG. 3 , the propelling gasses may then act on gas piston  26  and may move gas piston  26  rearward in gas piston chamber  24 . Rearward movement of gas piston  26  may compress gas piston spring  40  against forward surface  42  of bolt carrier  20  and may compress return spring  46  against surface  48  of receiver  12 . Bolt carrier  20  may be restrained from rearward translation by the upward locking position of locking lever  22 . Locking lever  22  may be held in place because trigger  16  may continue to be positioned rearward by the firearm user. 
     In  FIG. 4 , gas piston  26  is at full compression and has reached the end of its rearward travel. Energy from the propelling gases may be stored in compressed gas piston spring  40 . Gas piston  26  may be prevented from translating forward by piston catch  34 . Piston catch  34  was rotated downwardly ( FIG. 3 ) by head  44  of piston  26  as head  44  slid over piston catch  34 . When head  44  cleared piston catch  34 , piston catch  34  was rotated upwardly by forward surface  42  of bolt carrier  20  acting on spring-loaded detent  38 . 
     Firearm  10  may remain in the position shown in  FIG. 4  until bolt carrier  20  is allowed to move. When the firearm user releases trigger  16 , locking lever  22  may be rotated downwardly ( FIG. 5 ), thereby freeing bolt carrier  20  to move rearward under the force of compressed gas piston spring  40  acting on forward surface  42 . Piston catch  34  may remain in its upward position by continued pressure from piston head  44 . Piston catch  34  may remain in its upward position even as bolt carrier  20  moves rearward. Piston catch  34  may restrain head  44  of gas piston  26 , thereby allowing the stored energy of gas piston spring  40  to act against bolt carrier  20 . 
     Rearward movement of bolt carrier  20  may partially cycle the firearm  10 . Partial cycling may include unlocking the bolt (not shown), extracting and ejecting a spent cartridge case (not shown), cocking the firing components (not shown), and further compressing return spring  46 . Piston catch  34  may rotate to its downward position ( FIG. 6 ) after bolt carrier  20  has translated rearward and pressure from gas piston spring  40  has been released. 
     When bolt carrier  20  reaches the rearward end of its travel, as shown in  FIG. 6 , return spring  46  may be compressed and protrusion  32  on rear surface  30  of gas piston  26  may be in contact with bolt carrier  20 . Compressed return spring  46  may now translate gas piston  26  forward. Because of the contact of the protrusion  32  on bolt carrier  20 , bolt carrier  20  may also be translated forward, as shown in  FIG. 7 . As bolt carrier  20  moves forward, the firearm cycle of operation may be completed. For example, the next round of ammunition may be chambered and the bolt (not shown) locked. 
     While the invention has been described with reference to certain preferred embodiments, numerous changes, alterations and modifications to the described embodiments are possible without departing from the spirit and scope of the invention as defined in the appended claims, and equivalents thereof.