Drum magazine assembly and methods

Patent metadata

Field	Value
Publication number	US-10184741-B2
Application number	US-201615354492-A
Country	US
Kind code	B2
Filing date	Nov 17, 2016
Priority date	Oct 14, 2014
Publication date	Jan 22, 2019
Grant date	Jan 22, 2019

Abstract

A magazine assembly for a firearm and a related method are disclosed. The assembly has a magazine housing defining a track, and a follower assembly. The magazine housing is configured to constrain a cartridge as the cartridge is moved within the magazine assembly such that majority of a proximal surface area of the cartridge does not contact the magazine housing, and a distal tip of the cartridge does not contact the magazine housing.

First claim

What is claimed is:

1. A magazine assembly for a firearm, comprising:
a magazine housing defining a track; and
a follower assembly; wherein
the magazine housing comprises proximal abutting surfaces on opposing sides of the track, the proximal abutting surfaces configured to simultaneously contact and constrain a cartridge as the cartridge is moved within the magazine assembly such that focal points of the cartridge and of at least one other cartridge substantially converge at a single point during the cartridges' movement along at least a majority of the track, and such that a majority of a proximal surface area of the cartridge does not contact the magazine housing, and a distal tip of the cartridge does not contact the magazine housing.

2. The magazine assembly of claim 1 , wherein:
the magazine is a drum magazine; and
the magazine housing comprises a drum body and a rear cover.

3. The magazine assembly of claim 2 , wherein:
the drum body and the rear cover are coupled together to define the track therebetween, and to constrain a cartridge therebetween.

4. The magazine assembly of claim 1 , further comprising:
a track ridge for abutting a proximal surface of the cartridge.

5. The magazine assembly of claim 4 , wherein:
the track ridge is configured to abut a minority of a proximal surface area of the cartridge.

6. The magazine assembly of claim 1 , wherein:
the proximal abutting surfaces constrain the focal point of the cartridge.

7. The magazine assembly of claim 1 , wherein:
the magazine housing comprises a distal abutment to abut a case of the cartridge.

8. The magazine assembly of claim 7 , wherein:
the distal abutment is configured to prevent a tip of the cartridge from striking the magazine housing.

9. The magazine assembly of claim 8 , wherein:
the distal abutment is configured to constrain the focal point of the cartridge.

10. The magazine assembly of claim 1 , further comprising:
a viewing window.

11. The magazine assembly of claim 10 , further comprising:
at least one of a transparent cover over the viewing window or a semi-transparent cover over the viewing window.

12. The magazine assembly of claim 1 , wherein:
at least a portion of the magazine housing comprises at least one of a transparent material or a semi-transparent material.

13. The magazine assembly of claim 1 , wherein:
the track is a spiral track, the spiral track winding about a central axis at a discontinuously increasing rate.

14. The magazine assembly of claim 1 , wherein:
the track is a spiral track, the spiral track winding about a central axis at a continuously increasing rate.

15. The magazine assembly of claim 1 , wherein:
the track is a spiral track; wherein
the spiral track has portions winding about a central axis at a discontinuously increasing rate; and the spiral track has portions winding about the central axis at a constant radius.

16. A method of constraining a cartridge in a magazine assembly for a firearm, comprising:
providing a magazine housing defining a track;
providing a follower assembly;
constraining the cartridge with proximal abutting surfaces, of the magazine housing, on opposing sides of the track, the proximal abutting surfaces simultaneously contacting two opposing sides of the cartridge and constraining the cartridge as the cartridge is moved within the magazine assembly such that:
a majority of a proximal surface area of the cartridge does not contact the magazine housing;
a distal tip of the cartridge does not contact the magazine housing; and
the cartridge is constrained to substantially a same focal point as at least one other cartridge in the magazine during at least a majority of both cartridges' movement along the track.

17. The method of claim 16 , further comprising:
causing a track ridge to abut a proximal surface of the cartridge.

18. The magazine method of claim 17 , further comprising:
supporting a minority of the proximal surface area of the cartridge.

19. The method of claim 16 , further comprising:
abutting a distal portion of a case of the cartridge.

20. A magazine assembly for a firearm, comprising:
a magazine housing defining a track with nearly-concentric spirals; and
a follower assembly; wherein
the magazine housing comprises proximal abutting surfaces on opposing sides of the track configured to simultaneously contact and constrain a cartridge as the cartridge is moved within the magazine assembly such that focal points of the cartridge and of at least one other cartridge substantially converge at a single point during the cartridges' movement along at least a majority of the track, and such that the cartridge is pointed at a focal point as the cartridge is moved.

21. The magazine assembly of claim 20 , wherein:
the magazine is a drum magazine; and
the magazine housing comprises a drum body and a rear cover.

22. The magazine assembly of claim 21 , wherein:
the drum body and the rear cover are coupled together to define the track therebetween, and to constrain the cartridge therebetween.

23. The magazine assembly of claim 20 , further comprising:
a track ridge for abutting a proximal surface of the cartridge.

24. The magazine assembly of claim 23 , wherein:
the track ridge is configured to abut a minority of a proximal surface area of the loaded cartridge.

25. The magazine assembly of claim 20 , wherein:
the magazine housing comprises a distal abutment to abut a case of the cartridge.

26. The magazine assembly of claim 25 , wherein:
the distal abutment is configured to prevent a tip of the cartridge from striking the magazine housing.

27. The magazine assembly of claim 26 , wherein:
the distal abutment is configured to constrain the focal point of the cartridges.

28. The magazine assembly of claim 20 , further comprising:
a viewing window.

29. The magazine assembly of claim 28 , further comprising:
at least one of a transparent cover over the viewing window or a semi-transparent cover over the viewing window.

30. The magazine assembly of claim 20 , wherein:
at least a portion of the magazine housing comprises at least one of a transparent material or a semi-transparent material.

31. The magazine assembly of claim 20 , further comprising:
a spiral track, the spiral track winding about a central axis at a discontinuously increasing rate.

32. The magazine assembly of claim 20 , wherein:
the track is a spiral track, the spiral track winding about a central axis at a continuously increasing rate.

33. The magazine assembly of claim 20 , wherein:
the track is a spiral track; wherein
the spiral track has portions winding about a central axis at a discontinuously increasing rate; and the spiral track has portions winding about the central axis at a constant radius.

Assignees

• Magpul Ind Corp

Inventors

• Roberts Timothy Eric
• Mayberry Michael T
• Nakayama Brian L
• Fitzpatrick Richard M
• Nakayama Eric
• Bennett William Bradley

Classifications

• F41A9/70

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

• F41A9/75 Primary

  having a spiral cartridge channel · CPC title

• F41A9/61 Primary

  Magazines · CPC title

• F41A9/73

  Drum magazines · CPC title

• F41A9/65

  Box magazines having a cartridge follower · CPC title