Double stack magazine for firearm

Patent metadata

Field	Value
Publication number	US-12498189-B2
Application number	US-202418639860-A
Country	US
Kind code	B2
Filing date	Apr 18, 2024
Priority date	Apr 19, 2023
Publication date	Dec 16, 2025
Grant date	Dec 16, 2025

Abstract

A double stack magazine for a firearm comprises a tubular magazine body defining a cavity for holding a stack of cartridges, a spring, and a follower biased by the spring for dispensing cartridges from the magazine. The cartridges may be rimmed cartridges in one embodiment arranged in a vertically staggered side-to-side arrangement. The magazine includes a lower double stack section and upper single stack section. The follower includes angled front and rear cartridge feed surfaces each configured to exclusively engage the cartridge stack at alternate times depending on whether cartridges are present in the lower double stack section. The magazine further includes a pair of non-linear cartridge convergence ribs configured to engage the cartridge stack and force the projectile ends thereof together in the upper single stack section to center an uppermost cartridge in the stack for dispensing from the magazine to the firearm for chambering.

First claim

What is claimed is:

1 . A double stack magazine for a firearm comprising:
an elongated tubular magazine body defining a vertical centerline and an internal cavity configured to hold a stack of rimmed cartridges, the magazine body including an at least partially open top end, a bottom end, a front wall, a rear wall, and opposed lateral sidewalls extending between the front and rear walls; the magazine body including a lower double stack section configured to hold a vertically staggered double stack of the cartridges, an upper single stack section, and a transition section formed between the double stack section and the single stack section; a spring disposed in the cavity; a follower moveably disposed in the cavity and biased in an upwards direction towards the top end of the magazine body by the spring; the follower comprising a rear cartridge feed surface and adjoining front cartridge feed surface each configured to selectively engage and support an ammunition cartridge, the rear feed surface being disposed at an oblique angle to the front feed surface ; the front and rear cartridge feed surfaces each configured to engage and support a lowermost cartridge of the stack at alternate different times depending on a number of cartridges present in the stack.

2 . The magazine according to claim 1 , wherein the front cartridge feed surface is sloped at a first angle from 0 degrees to about and including 20 degrees with respect to a horizontal reference plane oriented perpendicularly to the vertical centerline of the magazine, and the rear cartridge feed surface sloped in an upwards direction from rear to front at a second angle with respect to the horizontal reference plane which is greater than the first angle.

3 . The magazine according to claim 2 , wherein the front cartridge feed surface and the second cartridge feed surface are each flat and meet at an apex therebetween.

4 . The magazine according to claim 1 , wherein the front cartridge feed surface does not engage the lowermost cartridge in the stack when the rear cartridge feed surface engages the lowermost cartridge in the stack, and vice-versa.

5 . The magazine according to claim 4 , wherein:
the front cartridge feed surface is configured to engage a front half of the lowermost cartridge in the double stack section when at least one cartridge is present below the transition section of the magazine body; and the rear cartridge feed surface is configured to engage a rear half of the lowermost cartridge in the stack in the single stack section when there are no cartridges present below the transition section of the magazine body.

6 . The magazine according to claim 1 , wherein the transition section comprises a pair of laterally spaced apart non-linear cartridge convergence ribs each having an arcuately curved configuration, the cartridge convergence ribs being configured to engage sides of the cartridges to transition and center the cartridges when fed from the lower double stack section to the upper single stack section.

7 . The magazine according to claim 6 , wherein the lateral sidewalls are parallel to each other in the lower double stack section and converge towards each other in the upper single stack section moving upwards to the open top end of the magazine body.

8 . The magazine according to claim 7 , wherein the non-linear cartridge convergence ribs are disposed in a front half of the magazine body forward of a pair of inwardly extending feed lips defined in a rear half of the magazine at the open top end.

9 . The magazine according to claim 8 , further comprising a pair of laterally spaced apart linear cartridge guide ribs formed below the feed lips in the rear half of the magazine, the linear guide ribs configured to engage sides of the cartridges farther rearwards than the non-linear guide ribs.

10 . The magazine according to claim 6 , wherein the spring defines a spring axis which is parallel to and offset from the vertical centerline of the magazine body.

11 . The magazine according to claim 10 , wherein the spring is a helical compression spring comprising a plurality of circular coils collectively defining a diameter of the coils.

12 . The magazine according to claim 11 , wherein the spring is disposed in a front half of the magazine body and a top end of the spring only engages the follower beneath the front cartridge feed surface.

13 . The magazine according to claim 12 , wherein the front cartridge feed surface has a length measured between the front and rear walls which is equal to or greater than the diameter of the coils of the spring.

14 . The magazine according to claim 1 , wherein the lateral sidewalls of the magazine body each include a vertically elongated guide slot, the guide slot slideably receiving a laterally extending guide pin affixed to the follower which cooperate to guide upward and downward movement of the follower in the magazine body in a manner that resists rotation of the follower with respect to the magazine body.

15 . The magazine according to claim 14 , wherein the follower further comprises a pair of laterally extending guide protrusions each of which slideably engage a respective vertically elongated guide channels formed in each lateral sidewall of the magazine body which further guides upward and downward movement of the follower in the magazine body in a manner that resists rotation of the follower with respect to the magazine body.

16 . The magazine according to claim 14 , wherein the guide pin and guide protrusions of the follower are each disposed in a vertically elongated rear portion of the follower beneath the rear cartridge feed surface, the rear portion of the follower extending farther downwards in the magazine body than a front portion of the follower which defines the front cartridge feed surface.

17 . The magazine according to claim 1 , wherein the cartridges are .22 LR rimmed rimfire cartridges.

18 . The magazine according to claim 1 , wherein only the front cartridge feed surface engages and supports the lowermost cartridge in the stack when there are cartridges present in both the lower double stack section and the upper single stack section, and only the rear cartridge feed surface engages the lowermost cartridge in the when cartridges are present in only the upper single stack section.

19 . A pistol comprising a magazine well configured to removably receive the magazine according to claim 1 .

20 . The magazine according to claim 1 , wherein:
the follower comprises a front cartridge feed surface and a rear cartridge feed surface disposed at an obtuse angle to the front cartridge feed surface; the front cartridge feed surface being configured to engage a lowermost cartridges in the stack when cartridges are present in the lower double stack section of the magazine; and the rear cartridge feed surface being configured to engage the lowermost cartridges in the stack when cartridges are not present in the lower double stack section of the magazine.

21 . The magazine according to claim 20 , wherein the rear cartridge feed surface is disposed at a first angle to a horizontal reference plane of the magazine and the front cartridge feed surface is disposed at a second angle to the horizontal reference plane, the first angle being larger than the second angle.

22 . The magazine according to claim 20 , wherein the front and rear cartridge feed surfaces are flat.

Assignees

• Sturm Ruger & Co

Inventors

• Giles Jacob
• Vuksanovich Brian
• Putnam Heath

Classifications

• F41A9/70

  Arrangements thereon for discharging, e.g. cartridge followers or discharge throats · CPC title

• F41A9/69 Primary

  characterised by multiple-row or zigzag arrangement of cartridges · CPC title