Ratcheting magazine assembly

1. A magazine for a firearm comprising:

a main body comprising an upper end and a lower end;

a first opening at the upper end of the main body such that cartridges exit the magazine through the first opening;

a floor plate at the lower end of the main body;

a second opening separate from the first opening such that cartridges enter the magazine through the second opening; and

an insert disposed inside the main body, wherein:

the insert comprises a front column of supports, a rear column of supports, and a sliding column of supports; and

the sliding column of supports comprises a plurality of positions relative to the insert such that the sliding column of supports moves relative to the insert.

2. The magazine of claim 1 , wherein the second opening is disposed at least as close to the lower end as to the upper end.

3. The magazine of claim 1 , wherein the second opening is disposed at the lower end of the main body.

4. The magazine of claim 1 , wherein the second opening is disposed in the floor plate.

5. The magazine of claim 1 , wherein the insert is a separate component from the main body.

6. The magazine of claim 1 , further comprising a plurality of arms adjacent to the second opening, wherein the plurality of arms restrict movement of cartridges out of the magazine.

7. The magazine of claim 1 , wherein each of the supports of the front column of supports, the rear column of supports, and the sliding column of supports comprises a deployed position and a retracted position.

8. The magazine of claim 1 , further comprising a rotating actuator that is mechanically linked to the movement of the sliding column.

9. The magazine of claim 8 , wherein the rotating actuator comprises a hole for a mechanical connection between the rotating actuator and the sliding column.

10. The magazine of claim 8 , wherein the rotating actuator comprises a protrusion extending upward from the magazine.

11. The magazine of claim 10 , wherein the protrusion of the rotating actuator is configured to interface with a bolt carrier group when the magazine is inserted into the firearm.

12. The magazine of claim 11 , wherein movement of the protrusion of the rotating actuator from a rear position to a front position cause the sliding column to move from a lowermost position to an uppermost position.

13. A magazine for a firearm comprising:

a main body;

a floor plate; and

an insert disposed inside the main body, wherein:

the insert comprises at least one static support and at least one sliding support;

the at least one sliding support comprises a plurality of positions relative to the insert such that the at least one sliding support moves relative to the insert; and

each of the supports of the at least one static support and the at least one sliding support comprises a deployed position and a retracted position.

14. The magazine of claim 13 , further comprising:

a first opening adjacent to an upper end of the main body such that cartridges exit the magazine through the first opening; and

a second opening separate from the first opening such that cartridges enter the magazine through the second opening.

15. The magazine of claim 14 , wherein the second opening is disposed at least as close to a lower end as to the upper end.

16. The magazine of claim 14 , wherein the second opening is disposed at the lower end of the main body.

17. The magazine of claim 14 , wherein the second opening is disposed in the floor plate.

18. The magazine of claim 14 , further comprising a plurality of arms adjacent to the second opening, wherein the plurality of arms restrict movement of cartridges out of the magazine.

19. The magazine of claim 13 , wherein the insert is a separate component from the main body.

20. The magazine of claim 13 , further comprising an actuator that is mechanically linked to the movement of the at least one sliding support.