Patent Application
20200011623
Embodiments of the present disclosure generally relate to firearm magazines. More specifically, the disclosure relates to an improved high capacity magazine design that allows for the feeding of ammunition without the use of feed ramps and/or allows an existing magazine to be used for larger cartridges than the magazine's original design.
Magazines for automatic and semi-automatic firearms are often of the high capacity design to provide the firearm with a reasonable amount of ammunition. Magazines can be comprised of metal, various polymers, or any other suitable material, including a combination of materials. Magazines may be made as one piece of folded material or as multiple sections attached together.
To maximize the use of the space inside the magazine, and to keep the magazine as small as possible, the ammunition is often arranged in a “double stack” configuration to reach the high capacity desired. Double stack refers to the two vertical columns of cartridges arranged next to each other in a staggered zigzag pattern (See
Magazine 100 has a coil type spring 104 on the inside of magazine 100 that extends from the bottom of magazine 100 to the top. Floor plate 112 is at the bottom of magazine 100. On top of the spring 104 is a plastic or metal piece called a follower 106 formed to guide the cartridges 114 into place as the cartridges are loaded into magazine 100. As magazine 100 is loaded, spring 104 compresses until magazine 100 is fully loaded. The cartridges 114 are contained inside magazine 100 by feed lips 108 at the top of magazine 100. There are two feed lips 108 on a double stack/double feed configured magazine, one on each side of the magazine. Feed lips 108 are curved pieces of metal or plastic that are attached to and extend from the sides of magazine 100. Feed lips 108 are curved at a desired angle to maintain the top-positioned cartridge 114 in position in the magazine 100. As shown in
Cartridges 114 are held up against the underside of feed lips 108 by the upward force exerted by magazine spring 104. There is a space (bolt channel 110) between the inside edges of the two feed lips 108 to allow the firearm's bolt to pass through as the bolt moves forward and pushes cartridges 114 out of magazine 100 and into the chamber of the firearm.
Conventional double stack/double feed magazines have several benefits, such as maximizing the space available to contain as many cartridges as possible while keeping the magazine as small as possible. However, there are also drawbacks to the conventional double stack design. As mentioned above, double stack configured magazines utilize a feed lip on each side of the magazine to contain and align the cartridges in a horizontal tip forward position.
The chamber of a firearm is located in the center of the barrel. A double stack/double feed configured magazine presents the cartridges in a low offset position as the cartridges relate to the chamber of the firearm, with each stack of cartridges off to a side of and just below the chamber, as illustrated in
When the cartridge is pushed forward by the bolt as the firearm cycles, it is moved with a great amount of force and velocity. When the projectile in the cartridge engages the steel feed ramp 202 with this force, the tip of the projectile can be dented or deformed which degrades the aerodynamic properties of the projectile thereby reducing accuracy of the projectile.
Additionally, hunters often use soft point ammunition with exposed soft lead tips that are required for hunting and that accelerate the expansion of the projectile. These exposed lead tips can be severely damaged by the feed ramps 202, degrading the accuracy of the hunting ammunition and resulting in wounded or wasted animals.
Another drawback to the use of feed ramps 202 in barrel extensions of semi-automatic and automatic firearms to deflect and direct the cartridges into the chamber 204 of the firearm is that each feed ramp 202 is located just below a bolt lug recess cut into the barrel extension. Bolt lug recesses 206 are illustrated in
The bolt lug recesses 206 have a square shape with sharp edges 208 on all three sides. As the cartridge is deflected into the chamber, the projectile impacts the feed ramps 202 and passes through the bolt lug recess 206. As the cartridge passes through, the projectile often comes into contact with the sharp edges 208 which can further damage the jacket of the projectile and further degrade the projectile's accuracy. The damage to the projectile by the barrel extensions' sharp lug recess edges 208 becomes more severe as the caliber of the projectile increases. Smaller caliber projectiles that are close to the width of the recess 206 may pass through with little or no damage, but larger caliber projectiles can receive major damage as the large projectile attempts to pass through the narrow recess 206. Feeding of large projectiles can even cause enough of a drag as the projectile's jacket digs into the sharp edges of the recess 206 to slow down the bolt of the firearm and cause the firearm to malfunction.
Military and law enforcement snipers as well as civilian competition shooters often prefer semiautomatic rifles and use match ammunition loaded with match grade projectiles that deliver excellent accuracy at extreme distances. Match grade projectiles are manufactured to exacting tolerances for consistency, including almost identical weights, jacket thickness concentricity, aerodynamic profiles, and perfectly formed tips. When these match grade projectiles engage the steel feed ramps 202 and sharp edges 208 of the bolt lug recesses 206, the match grade projectiles are often deformed which is detrimental to the precision design of the match grade projectiles and defeats the intended purpose of the match grade projectiles for improved long range accuracy. Degraded accuracy of match ammunition used by military and law enforcement snipers could mean the difference between life and death for a hostage or bystanders.
The most common semiautomatic firearm in use today by the military, law enforcement and civilian shooters is the AR15 (or AR10) style rifle. One of the reasons for the popularity of the AR15 style rifle is the modular two piece design of the AR15 style rifle which allows the upper and lower receivers to be exchanged with alternative upper or lower receivers. This modular design allows the owner of one lower receiver to have multiple upper receivers, and therefore multiple calibers for one firearm. The lower receiver contains the magazine well, which is the recess where the magazine is inserted into the firearm. The magazine well is a fixed size and only accepts one size of magazine.
While the upper receiver of the firearm can be replaced easily to change from one caliber or cartridge to another, altering the magazine to accept additional cartridges is not as easy. The double stack/double feed design magazines for AR15 type (or AR10) rifles have been slightly modified successfully to accept several slightly larger cartridges, but the double stack design magazine also has limitations to the size of cartridges the double stack magazine can accept. The two major limiting factors are feed lip adaptability and stack geometry.
As discussed above, feed lips 108 are metal flaps attached to the sidewall of the magazine 100 that are bent over the top of the magazine 100 to contain the cartridges 114 inside the magazine 100 and to help guide the cartridges 114 into the chamber 204. Feed lips 108 are curved at an angle to retain the cartridge case, for which the magazine was designed, in the magazine. There is also a minimum amount of space required between the feed lips 108 for the bolt of the firearm to pass through (i.e., the bolt channel 110) as it pushes the cartridges 114 out of the magazine 100 and into the chamber 204 (see, e.g.,
As the cartridge case becomes larger in diameter, the tip of the projectile is located in a lower position as it relates to the feed ramp 202 when compared to a smaller diameter cartridge case because the feed lips 108 are in a fixed location and cannot be moved. For example, a cartridge position 220 for a double feed magazine is illustrated with an arrow in
Stack geometry refers to the way the cartridges 114 position themselves and move inside the magazine 100 when the magazine is loaded. Magazines are originally designed and built for a specific cartridge. A traditional double stack type of magazine has a width to accommodate two vertical columns of selected cartridges side by side in a zigzag pattern from top to bottom, as illustrated in
The width of the cartridge stack in a traditional double stack magazine is approximately 188% of the width of the cartridge case, measured at the rear of the case. In this configuration, each cartridge in the stack, except for the top and bottom cartridges, is touching at least two other cartridges in the stack. Some of the cartridges may touch three or four other cartridges in the stack.
As mentioned above, the magazine has a predetermined physical size to which the magazine is limited to accommodate the magazine well of the firearm. When attempting to modify the magazine to accept larger diameter cases, the “stack geometry” inside the magazine changes. The internal dimensions of the magazine cannot be made larger or modified much because the double feed configuration requires a cartridge under each feed lip 108 on each side of the magazine. As the cartridge cases get larger in diameter the cartridge cases will have larger spaces therebetween when the magazine is loaded, which creates an outward force on the sides of the magazine. The left side of
When this happens, the cartridges in the magazine do not move up and down freely inside the magazine and can actually cause a bulge in the outer walls of the magazine. This can cause the cartridges to jam together inside the magazine, causing a feed jam and the firearm to malfunction. This bulging of the magazines side walls also makes it difficult to insert and release the magazine from the firearm. Double stack/double feed types of magazines can therefore be modified to accept cartridges larger than originally designed, but only minimally.
When attempting to narrow the width of the double stack of cartridges there is a width or range that alters the up and down forces of the double stack of cartridges and redirects the forces on the cartridges to the outside walls of the magazine (see, e.g.,
This “failure or wedge zone” where the cartridges exert forces to the outside walls of the magazine is from approximately 150% to 180% percent of the width of the cartridge case. Previous attempts to adapt larger cartridges to existing magazines have resulted in failure because they have attempted to adapt the cartridges to a stack width that falls in this failure zone.
What is needed is an improved magazine design for semiautomatic and automatic rifles, as well as a design that can be adapted for bolt action rifles.
The present disclosure generally relates to firearm magazines for automatic and semi-automatic firearms, and more particularly to a design that allows for the advantages of a double stack magazine for high capacity while utilizing a single feed style mechanism for positioning and guiding the cartridges into the chamber. An improved magazine design allows for the use of larger diameter cartridges other than what the magazine was originally designed for, allowing larger diameter cartridges for use in smaller firearms. In military applications, larger diameter cartridges may be more effective against armor used by opposing forces. Embodiments described herein allow an existing lower receiver to shoot larger diameter cartridges without requiring the purchase of a new weapon. An improved magazine design also utilizes a single feed design, allowing the internal width of the magazine to be adjusted to provide a good stack geometry without affecting the feeding of the cartridges from the magazine.
In one aspect, a firearm magazine includes a magazine body, with the magazine body having a width to accommodate a double stack of cartridges in a zigzag pattern. The firearm magazine also includes a spring coupled to a follower within the magazine body. The firearm magazine body also includes two feed lips coupled to the magazine body, where the two feed lips together hold a single cartridge in place in a center position of the magazine body to allow a bolt to push the single cartridge out of the firearm magazine and into a chamber of a firearm.
So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only exemplary embodiments and are therefore not to be considered limiting of its scope, as the disclosure may admit to other equally effective embodiments.
To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements and features of one embodiment may be beneficially incorporated in other embodiments without further recitation.
The present disclosure generally relates to firearm magazines, and more specifically to a design that allows for the advantages of a double stack magazine for high capacity while utilizing a single feed style mechanism for positioning and guiding the cartridges into the chamber.
Embodiments described herein maintain the double stack configuration for the loaded cartridges but utilize a single feed design instead of the traditional double feed design. As mentioned previously, the double feed design has two feed lips—one on each side of the magazine which holds the top cartridge in each stack in place. Therefore each feed lip retains one cartridge (i.e., the top cartridge is retained by one feed lip). The double stack/single feed design has one set of feed lips that position one cartridge in the center top of the magazine. Therefore, both feed lips retain a single cartridge in the center position. The feed lips of the single feed design are curved to direct the cartridges into the single feed position but do not need to be shaped to match the curvature of the cartridge case. Instead, the feed lips are angled inward from each side of the magazine at an angle that best guides the cartridges, depending on diameter, from each stack into the center of the magazine and into the single feed position.
Embodiments described herein may utilize a narrow double stack cartridge configuration or a wide double stack cartridge configuration. In the narrow double stack cartridge configuration, each cartridge in the fully or almost fully loaded magazine touches two other cartridges, except for the top and bottom cartridges, which only contact one other cartridge (see, e.g.,
In the wide double stack cartridge configuration, each cartridge in the fully or almost fully loaded magazine touches three or four other cartridges, except for the top and bottom cartridges, which may only touch one or two other cartridges (see e.g.,
In another embodiment, a magazine body may comprise a first section with a first width where the cartridges are arranged in a narrow double stack cartridge configuration, and may also comprise a second section with a second width where the cartridges are arranged in a wide double stack cartridge configuration, as discussed with respect to
The double stack magazine 300 with a single feed design utilizes a similar internal design to store the cartridges as the double stack/double feed high capacity magazine described above in
In the narrow double stack cartridge configuration, each cartridge in the fully or almost fully loaded magazine touches two other cartridges, except for the top and bottom cartridges, which only contact one other cartridge. In the narrow double stack cartridge configuration, the width of the cartridge stack is approximately less than 150% of the width of the cartridge case. Thus, the width of the cartridge stack is outside of the failure zone as described above.
In the wide double stack cartridge configuration, each cartridge in the fully or almost fully loaded magazine touches three or four other cartridges, except for the top and bottom cartridges, which may only touch one or two other cartridges. In the wide double stack cartridge configuration, the width of the cartridge stack is approximately greater than 180% of the width of the cartridge case. Thus, the width of the cartridge stack is outside of the failure zone as described above.
Although the double stack/single feed magazine design illustrated in
The single feed design also requires less force from the bolt as the firearm cycles because the cartridge is easily fed from the magazine and into the chamber with less resistance. The double feed design, in contrast, requires more force from the bolt to overcome the resistance created when the cartridges engage the feed ramps and are redirected into the chamber. As the projectile in the cartridge engages the feed ramp as the cartridge moves forward, the rear half of the cartridge case is still under the feed lip. As the front of the cartridge is deflected up due to the contact with the feed ramp, the rear of the cartridge is deflected down and must push the remaining cartridges in the magazine down and compress the magazine spring until the rear of the cartridge is pushed out from under the feed lip. This movement also causes resistance on the bolt as the cartridge is fed from the magazine.
The double stack/single feed magazine functions in much the same manner as a traditional double stack/double feed magazine in that the cartridges are removed or “stripped” from the magazine by the bolt as the firearm cycles. Both designs utilize a magazine spring that pushes the cartridges up from the bottom of the magazine and “feeds” them as the firearm cycles, while the cartridges are retained in the magazine by the feed lips at the top of the magazine.
The double stack/single feed design, however, allows the magazine feed lips to present the cartridge in a centered and more elevated position when compared to a traditional double stack/double feed design. A comparison of
Cartridges fed from a magazine with a single feed design will generally be more accurate than those from a traditional double feed design because the projectiles will not be damaged as the cartridges are fed from the magazine and into the chamber.
The structure of magazine 400 allows the narrower top portion of the magazine to fit into an existing smaller magazine well of a firearm, while the wider bottom portion allows for more rounds to fit into the magazine.
To disassemble one embodiment of the double stack/single feed magazine as described herein, the floor plate is removed by sliding the floor plate to the front or rear and off of the bottom of the magazine. Then, the coil spring and follower are removed by pulling them out the bottom of the magazine. Assembly of the magazine is in reverse order of disassembly.
Due to the single feed position in the center of the magazine having a bolt channel narrower than the cartridge case, loading of the cartridges must occur one at a time with the cartridges pushed into position from the front, which depresses the follower and slides the cartridge down and under the feed lips. Additional cartridges are fed the same way by depressing the cartridge that is already in the magazine down and sliding the next cartridge into the magazine on top of the one already in the magazine. The magazine is unloaded by sliding the cartridges out from under the feed lips from back to front one at a time until the magazine is empty.
The double stack/single feed magazine has a number of advantages over conventional magazines. First, the double stack/single feed magazine maintains the high capacity design of conventional magazines. Second, the double stack/single feed magazine does not damage projectiles as much as the conventional design. Finally, the double stack/single feed magazine is easily adaptable for use with larger diameter cartridges.
Some embodiments herein use semiautomatic and automatic firearms as examples, particularly semiautomatic and automatic rifles that utilize barrel extensions. Embodiments described herein may also be utilized in bolt action rifles that utilize feed ramps with appropriate modifications, if necessary. Embodiments herein may utilize any magazine capacity, from one round to forty rounds or even higher.
While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
