This invention relates to ammunition magazines for semiautomatic firearms.
Certain legal jurisdictions place limits on the capacity of magazines for semiautomatic firearms. As these jurisdictions are relatively few in number, and thus will generate a relatively small sales volume of reduced capacity magazines, it is advantageous to develop a reduced capacity magazine design which can be manufactured without the need for special tooling and the associated capital investment and expense over and above the expense and tooling needed for the manufacture of standard capacity magazines having a capacity determined by the design of the firearm and not by legislation.
This invention concerns a magazine for feeding ammunition to a firearm. In an example embodiment, the magazine comprises a tube surrounding a longitudinal axis and defining a central space for receiving the ammunition. The tube has first and second ends oppositely disposed. A follower is slidably movable within the tube along the longitudinal axis. A butt plate is removeably attached to the first end of the tube. The butt plate defines a bore extending therethrough. A plunger is movably positioned within the bore of the butt plate. The plunger comprises a first cam mounted thereon. A first catch is mounted on the butt plate and is engageable with the tube proximate to the first end thereof. The first catch is movable relatively to the butt plate in a direction transverse to the longitudinal axis. The first catch comprises a first cam follower engageable with the first cam. A spring acts between the plunger and the follower for biasing the plunger toward the butt plate and the follower toward the second end of the tube. The first cam acts on the first cam follower to position the first catch into engagement with the tube upon motion of the plunger toward the butt plate, thereby retaining the butt plate to the tube. The first cam acts on the first cam follower to position the first catch out of engagement with the tube, thereby releasing the butt plate from the tube upon motion of the plunger toward the follower.
As an example, the bore is oriented parallel to the longitudinal axis of the tube.
In an example, the magazine further comprises a first slot located within the tube proximate to the first end thereof. The first catch comprises a first shoulder projecting transversely to the longitudinal axis. The first shoulder is engageable within the first slot upon the motion of the plunger toward the butt plate.
As an example, the first cam comprises a first trunnion projecting from the plunger. The first cam follower comprises a first track positioned within the first catch. The first cam is received within the first track.
In an example, the magazine further comprises a piston positioned within the tube between the spring and the butt plate. The piston is engageable with the plunger for transmitting a biasing force from the spring thereto. In a particular example, the piston comprises a panel and a boss. The panel is movable along the longitudinal axis within the tube. The boss projects from the panel into the bore for engagement with the plunger.
As an example, the butt plate comprises a lowermost surface. The longitudinal axis of the tube is oriented at an angle to the lowermost surface.
In an example, the magazine further comprises a second cam mounted on the plunger. A second catch is mounted on the butt plate and engageable with the tube proximate to the first end thereof. The second catch is movable relatively to the butt plate in a direction transverse to the longitudinal axis. The second catch comprises a second cam follower engageable with the second cam. The second cam acts on the second cam follower to position the second catch into engagement with the tube upon motion of the plunger toward the butt plate, thereby retaining the butt plate to the tube. The second cam acts on the second cam follower to position the second catch out of engagement with the tube, thereby releasing the butt plate from the tube upon motion of the plunger toward the follower. In a particular example, the second cam is mounted on an opposite side of the plunger from the first cam. In another particular example, the second catch is mounted on an opposite side of the plunger from the first catch.
As an example, the magazine further comprises a second slot located within the tube proximate to the first end thereof. The second catch comprises a second shoulder projecting transversely to the longitudinal axis. The second shoulder is engageable within the second slot upon the motion of the plunger toward the butt plate.
In an example, the second cam comprises a second trunnion projecting from the plunger. The second cam follower comprises a second track positioned within the second catch. The second cam is received within the second track.
This invention further concerns a magazine for feeding ammunition to a firearm. The magazine comprises a tube surrounding a longitudinal axis and defining a central space for receiving the ammunition. The tube has first and second ends oppositely disposed. A follower is slidably movable within the tube along the longitudinal axis. A butt plate is removeably attached to the first end of the tube. The butt plate defines a bore extending therethrough. A plunger is movably positioned within the bore of the butt plate. The plunger comprises a first cam mounted thereon. First and second catches are mounted on the butt plate and engageable with the tube proximate to the first end thereof. The first and second catches are movable relatively to the butt plate in opposite directions to one another transverse to the longitudinal axis. The first catch comprises a first cam follower engageable with the first cam and the second catch comprises a second cam follower engageable with the second cam. A spring acts between the plunger and the follower for biasing the plunger toward the butt plate and the follower toward the second end of the tube. The first and second cams act on the first and second cam followers respectively to position the first and second catches into engagement with the tube upon motion of the plunger toward the butt plate, thereby retaining the butt plate to the tube. The first and second cams act on the first and second cam followers respectively to position the first and second catches out of engagement with the tube, thereby releasing the butt plate from the tube upon motion of the plunger toward the follower.
In an example, wherein the bore is oriented parallel to the longitudinal axis of the tube.
As an example, the magazine further comprises first and second slots located within the tube proximate to the first end thereof. The first catch comprises a first shoulder projecting transversely to the longitudinal axis and the second catch comprises a second shoulder projecting transversely to the longitudinal axis. The first and second shoulders are respectively engageable within the first and second slots upon the motion of the plunger toward the butt plate.
In an example, the first cam comprises a first trunnion projecting from the plunger. The first cam follower comprises a first track positioned within the first catch. The first cam is received within the first track. The second cam comprises a second trunnion projecting from the plunger. The second cam follower comprises a second track positioned within the second catch. The second cam is received within the second track.
As an example, the magazine further comprises a piston positioned within the tube between the spring and the butt plate. The piston is engageable with the plunger for transmitting a biasing force from the spring thereto. In a particular example, the piston comprises a panel and a boss. The panel is movable along the longitudinal axis within the tube. The boss projects from the panel into the bore for engagement with the plunger.
In an example, the butt plate comprises a lowermost surface. The longitudinal axis of the tube is oriented at an angle to the lowermost surface. As an example, the second cam is mounted on an opposite side of the plunger from the first cam. In an example, the second catch is mounted on an opposite side of the plunger from the first catch.
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The magazine 10 with the butt plate retention mechanism described herein is expected to provide a reduced capacity magazine design which can be manufactured without the need for special tooling and the associated capital investment and expense over and above the expense and tooling needed for the manufacture of standard capacity magazines having a capacity determined by the design of the firearm.
This application is based upon and claims benefit of priority to U.S. Provisional application No. 62/932,695, filed Nov. 8, 2019, which application is hereby incorporated by reference herein.
Number | Date | Country | |
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62932695 | Nov 2019 | US |