This all I know of this type of feeding device.
Here are the loading instructions.
75 Round Magazine Instructions
TO LOAD MAGAZINE
1.) Unlatch and open the rear cover. Depress the spring loaded button in the center of the drum and turn the spindle clockwise until the magazine follower is returned to the beginning of the spiral track.
2.) Insert five (5) rounds into the slots located nearest the top (column) section of the magazine.
3.) With five rounds loaded, hold the spindle firmly in place with one hand. With the other hand, wind the spring tensioning key (located under the spring loaded button) CLOCKWISE three (3) clicks.
CAUTION: Hold the spindle securely while applying tension in order to prevent it from slipping and catching your fingers.
4.) With the spring tensioned, quickly release the spindle. The five rounds loaded previously will be pushed to the top of the magazine, and the last round will hold the spindle in place.
5.) At this point you have the option as to how to load the magazine. If cartridges are dropped in the remaining slots, the total magazine capacity will be seventy three (73) rounds. Alternately, if the procedure described as follows is used, the total capacity will be seventy five (75) rounds.
5A.) Tilt the column portion of the drum at a slight downward angle and turn the spindle clockwise just slightly. Remove the last two rounds.
5B.) Keep the drum tilted downwards, and rotate the spindle so that the follower is returned to the beginning of the spiral track (as in step 1).
5C.) Insert two rounds in the top section and release the spindle. Complete loading the magazine by dropping cartridges into the remaining slots.
WARNING: THE ABOVE PROCEDURES SHOULD ONLY BE USED WHEN LOADING THE MAGAZINE TO
ITS FULL CAPACITY OF 73 OR 75 ROUNDS. IF THE USER INTENDS TO LOAD ONLY A PARTIAL
MAGAZINE, THEN THE MAGAZINE FOLLOWER MUST BE DIRECTLY BEHIND THE LAST CARTRIDGE. IF
THERE IS A GAP BETWEEN THE LAST CARTRIDGE AND THE MAGAZINE FOLLOWER, THE DRUM MAY
BE DAMAGED DURING FIRING.
6.) With the drum fully loaded, close the rear cover and secure with both latches. Wind the mainspring with the key located on the rear cover. Wind the key seven (7) revolutions (360 degrees). If the magazine is loaded to only thirty (30) rounds, then the tension should be reduced to five (5) revolutions. DO NOT EXCEED THE RECOMMENDED NUMBER OF REVOLUTIONS AS THIS WILL CAUSE UNDUE WEAR OR BREAKAGE TO THE MAINSPRING.
With step six completed, the magazine is ready to use.
DURING PROLONGED PERIODS OF STORAGE:
Open the rear cover and depress the spring loaded button at the center of the drum. Do not tilt the drum, as the cartridges might fall out. Close and latch the back cover and re-tension the spring three (3) clicks. The drum magazine can be stored in this manner indefinitely.
TO UNLOAD THE MAGAZINE:
Open the rear cover and depress the spring loaded button at the center of the drum. Dump the cartridges out. The rounds in the column will need to be removed individually.
MAINTENANCE OF THE MAGAZINE:
Periodically, the magazine should be cleaned with solvent to prevent the build-up of unburned powder and grit in the spiral track. A significant amount of residue in the track may hinder the functioning of the drum.
To disassemble the drum magazine, open the real cover and depress the spring loaded button. Turn the spring tensioning key COUNTER-CLOCKWISE and remove it. Next, lift the spindle out of the magazine. DO NOT DISASSEMBLE THE MAGAZINE ANY FURTHER.
Krinkfreak, Jeepcreep,RS39 and TEMPLAR all swear this guy built it