Firearm Magazine Incorporating Spring Tension Relief Mechanism

Abstract

A magazine for use with semi-automatic and automatic firearms that includes a mechanism for relaxing the tension on the spring when the magazine is loaded with ammunition by lowering and extending the spring out of the bottom of the magazine. The magazine can be stored in a fully loaded configuration without concern that the spring will take on a compression set that will hamper its effectiveness in advancing ammo when the magazine is put to use in an associated firearm.

I claim: 
     
         1 . A ammunition magazine for a firearm comprising:
 an elongated body having substantially open body top and body bottom ends and sidewalls extending between the body top end and body bottom end defining a cavity, the cavity configured to receive a plurality of stacked rounds of ammunition therein, the body top end adapted to permit the exit of a topmost round of the plurality of rounds during use of the magazine in the firearm;   a coil spring having a spring top end and a spring bottom end at least partially contained within the cavity, the coil spring adapted to apply a biasing force against the plurality of rounds towards the body top end;   a base including a latch mechanism, the base configured for selective attachment to the body bottom end; and   an extension mechanism configured to lower and raise the base between first and second positions, the base being (i) in contact with and secured to the body bottom end in the first position and (ii) spaced a predetermined distance below body bottom end in the second position wherein the spring is spans the predetermined distance.   
     
     
         2 . The ammunition magazine of  claim 1 , further comprising an ammunition advancement plate coupled to the spring top end and a spring base plate coupled to the bottom end of the spring, the spring base plate being in contact with the base plate. 
     
     
         3 . The ammunition magazine of  claim 1 , further including the plurality of rounds of ammunition, the ammunition being contained within the cavity in a stacked configuration. 
     
     
         4 . The ammunition magazine of  claim 1 , wherein the base is in the second position. 
     
     
         5 . The ammunition magazine of  claim 1 , wherein the extension mechanism comprises a sleeve having a sleeve top end and a sleeve bottom end, the sleeve bottom end being attached to the base. The sleave being contained within the cavity in the first position and extending between the base and the body top end in the second position. 
     
     
         6 . The ammunition magazine of  claim 5 , wherein (1) the body bottom end includes opposing inwardly extending flanges, (2) the sleeve top end including opposing outwardly extending flanges, the inwardly and outwardly extending flanges interfacing when the base is in the second position to prevent the sleeve top end from sliding out of the body bottom end. 
     
     
         7 . The ammunition magazine of  claim 1 , wherein the extension mechanism comprises a plurality of interlocking sleeves, a bottom sleeve of the plurality of sleeves being attached to the base and a top sleeve of the plurality of sleeves including sleeve top end configured to interface with the body bottom end to retain the sleeve top end within the cavity proximate the body bottom end when the base is in the second position. 
     
     
         8 . The ammunition magazine of  claim 7 , wherein the body bottom end includes opposing inwardly extending flanges, (2) the sleeve top end includes opposing outwardly extending flanges, the inwardly and outwardly extending flanges interfacing when the base is in the second position to prevent the sleeve top end from sliding out of the body bottom end. 
     
     
         9 . The ammunition magazine of  claim 1 , wherein the extension mechanism comprises at least a pair of opposing rods each having a rod bottom end and a rod top end, The rod bottom ends being attached to the base and the rod top ends being configured to interface with the body to maintain a connection between the body and the rod top ends when the base is in the second position, the rods being received in the body when the base is in the first position. 
     
     
         10 . The ammunition magazine of  claim 1 , wherein the body further includes one or more openings through which contents of the cavity can be viewed. 
     
     
         11 . The ammunition magazine of  claim 3  in further combination with a firearm, the magazine being operatively coupled with the firearm. 
     
     
         12 . The ammunition magazine of  claim 1 , wherein the body bottom end includes opposing outwardly extending flanges and the latch mechanism includes opposing latches, the latches being configured to interface with the outwardly extending latches and secure the base to the body in the first position. 
     
     
         13 . A method of making an ammunition magazine of  claim 1  comprising:
 providing the elongated body; 
 providing the coil spring; 
 providing a base; 
 providing an extension mechanism; and 
 assembling the body, spring, base and extension mechanism to configure the magazine. 
 
     
     
         14 . The method of making the ammunition magazine of  claim 13 , further comprising, providing an ammunition advancement plate and a spring base plate. 
     
     
         15 . A method of using the ammunition magazine of  claim 1 , the method comprising:
 loading the magazine from the body top side with a plurality of rounds of ammunition; and   releasing the latch mechanism and lowering the base the predetermined distance from the first position to the second position and relaxing the coil spring.   
     
     
         16 . The method of  claim 15 , further comprising moving the base from the second position to the first position and securing the base to the body bottom end. 
     
     
         17 . The method of  claim 16 , further comprising loading the magazine into a firearm. 
     
     
         18 . A ammunition magazine for a firearm comprising:
 an elongated body having substantially open body top and body bottom ends and sidewalls extending between the body top end and body bottom end defining a cavity, the cavity configured to receive a plurality of stacked rounds of ammunition therein, the body top end adapted to permit the exit of a topmost round of the plurality of rounds during use of the magazine in the firearm, the body bottom end including a pair of opposing inwardly extending flanges;
 a coil spring having a spring top end and a spring bottom end at least partially contained within the cavity, the coil spring adapted to apply a biasing force against the plurality of rounds towards the body top end; 
 an ammunition advancement plate, the ammunition advancement plate resting on the spring top end; 
 a spring base plate coupled with the spring bottom end; 
 a base including a latch mechanism, the base configured for selective attachment to the body bottom end, the spring bottom end being biased against the base; and 
 an extension mechanism comprising a plurality of interlocking sleeves, a bottom sleeve of the plurality of sleeves being attached to the base and a top sleeve of the plurality of sleeves including sleeve top end configured to interface with the body bottom end to retain the sleeve top end within the cavity proximate the body bottom end when the base is in the second position, wherein the sleeve top end includes opposing outwardly extending flanges, the inwardly extending flanges and the outwardly extending flanges interfacing when the base is in the second position to prevent the sleeve top end from sliding out of the body bottom end. 
   
     
     
         19 . The ammunition magazine of  claim 18  wherein the body bottom end includes opposing outwardly extending flanges and the latch mechanism includes opposing latches, the latches being configured to interface with the outwardly extending latches and secure the base to the body in the first position. 
     
     
         20 . The ammunition magazine of  claim 19 , further including the plurality of rounds of ammunition, the ammunition being contained within the cavity in a stacked configuration.