Rotary ammunition magazine and follower
A rotary ammunition magazine for a rifle has a follower that is spring biased and rotates about an axis to move cartridges for feeding to the rifle's chamber. The follower has a rib and/or a projection on a surface facing the cartridges. The rib engages the last cartridge in a stack and directs the force from the follower in the direction of movement of the cartridges within the magazine. The projection engages the extractor groove in the last cartridge to prevent it from moving under inertial forces caused by recoil. The rib engages and prevents the last cartridge from moving down the follower. The projection and rib prevent bolt override malfunctions.
1. A follower for advancing cartridges in an ammunition magazine, said follower comprising:
a plate having a surface positionable within said magazine facing one of said cartridges, said plate having at least one edge oriented parallel to an axis of rotation of said plate;
a rib mounted on said surface in spaced relation to said at least one edge, said rib being engageable with said one cartridge;
a projection mounted on said surface in spaced relation to said at least one edge, said projection being engageable with a groove of said one cartridge.
2. The follower according to claim 1 , wherein said rib is oriented parallel to said at least one edge.
3. The follower according to claim 1 , wherein said rib comprises a flat surface engageable with said one cartridge.
4. The follower according to claim 1 , wherein said rib comprises a corner surface engageable with said one cartridge.
5. The follower according to claim 4 , wherein said corner surface comprises a radiused edge fillet.
6. The follower according to claim 1 , wherein said rib comprises a convexly curved surface engageable with said one cartridge.
7. The follower according to claim 1 , further comprising a bearing mounted on said at least one edge.
8. The follower according to claim 7 , wherein said bearing comprises at least one lug attached to said at least one edge, said at least one lug defining a bore coaxially aligned with said axis of rotation of said plate.
9. The follower according to claim 7 , wherein said bearing comprises first and second lugs attached to said at least one edge, said first and second lugs defining respective first and second bores coaxially aligned with said axis of rotation of said plate.
10. The follower according to claim 1 , wherein said rib is mounted on said surface in spaced relation to said axis of rotation.
11. The follower according to claim 1 , wherein said projection is mounted on said surface in spaced relation to said axis of rotation.
12. A magazine for holding a plurality of ammunition cartridges, said magazine comprising:
a plurality of sidewalls defining a space for receiving said cartridges;
an elongate opening defined between a first and a second of said sidewalls providing access to said space;
a follower mounted within said space, said follower being rotatable about an axis of rotation oriented parallel to said elongate opening for urging said cartridges toward said opening, said follower comprising:
a plate having a surface positioned facing one of said cartridges, said plate having at least one edge oriented parallel to said axis of rotation;
a rib mounted on said surface in spaced relation to said at least one edge, said rib being engageable with said one cartridge;
a spring biasing said plate for rotation about said axis of rotation.
13. The magazine according to claim 12 , wherein said rib is oriented parallel to said at least one edge.
14. The follower according to claim 12 , wherein said rib comprises a flat surface engageable with said one cartridge.
15. The follower according to claim 12 , wherein said rib comprises a corner surface engageable with said one cartridge.
16. The follower according to claim 15 , wherein said corner surface comprises a radiused edge fillet.
17. The magazine according to claim 12 , wherein said rib comprises a convexly curved surface engageable with said one cartridge.
18. The magazine according to claim 12 , further comprising a projection mounted on said first surface in spaced relation to said at least one edge, said projection being engageable with a groove of said one cartridge.
19. The magazine according to claim 12 , further comprising a shaft mounted within said space, said shaft being coaxial with said axis of rotation, said plate being mounted on said shaft.
20. The magazine according to claim 19 , further comprising a bearing mounted on said at least one edge, said bearing engaging said shaft.
21. The magazine according to claim 20 , wherein said bearing comprises at least one lug mounted on said at least one edge, said at least one lug defining a bore receiving said shaft.
22. The magazine according to claim 20 , wherein said bearing comprises first and second lugs attached to said at least one edge, said first and second lugs defining respective first and second bores receiving said shaft.
23. The magazine according to claim 19 , wherein one end of said shaft is supported on a third one of said sidewalls and an opposite end of said shaft is supported on a fourth one of said sidewalls, said third and fourth sidewalls being at opposite ends of said magazine.
24. The magazine according to claim 12 , wherein said spring comprises a coil spring acting between said plate and one of said sidewalls.