OA8578A - Drum Magazine. - Google Patents

Drum Magazine. Download PDF


Publication number
OA8578A OA59088A OA59088A OA8578A OA 8578 A OA8578 A OA 8578A OA 59088 A OA59088 A OA 59088A OA 59088 A OA59088 A OA 59088A OA 8578 A OA8578 A OA 8578A
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OA08578A (en
Leroy James Sullivan
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Beta Co
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Priority to US06/759,058 priority Critical patent/US4658700A/en
Application filed by Beta Co filed Critical Beta Co
Publication of OA8578A publication Critical patent/OA8578A/en
Publication of OA08578A publication Critical patent/OA08578A/en



    • F41WEAPONS
    • F41A9/00Feeding or loading of ammunition; Magazines; Guiding means for the extracting of cartridges
    • F41A9/61Magazines
    • F41A9/64Magazines for unbelted ammunition
    • F41A9/73Drum magazines
    • F41WEAPONS
    • F41A9/00Feeding or loading of ammunition; Magazines; Guiding means for the extracting of cartridges
    • F41A9/37Feeding two or more kinds of ammunition to the same gun; Feeding from two sides


A drum magazine (10) is disclosed for successively feeding a plurality of cartridges (21, 22) to a firearm (11). The magazine has drum shaped housing (12) having a cartridge exit opening (25) at the side of the housing. A rotational cartridge carrying means (16, 17) is disposed within the housing (12) to define a cartridge space (20) between the cartridge carrying means and the inner wall of the housing, for receiving two offset concentric rings of cartridges. A cam means (24) within the housing (12) defines, with the housing, a passage from the cartridge space to the exit opening of the housing means, for urging two offset concentric rings of cartridges (21, 22) alternately together into a single row when cartridges are moved out of the housing.


5 -1- •10 15 20 25
This invention relates to magazines forguns. More specifically it relates to largecapacity drum magazines which feed cartridges to anautomatic gun.
Drum magazines are we.ll known in the art.See for example, U. S. Patent No. 2,131,412 toOstman? U. S. Patent No. 4,138,923 to Brosseau? U. S. Patent No. 4,384,508 to Sullivan? and U. S.Patent No. 4,487,103 to Atchisson. The principaladvantage of drum magazines over the moreconventional box or column magazines is thëirgreater capacity, carrying two to four times thenumber of cartridges of a box magazine, withcorrespondingly more firepower. However, such drummagazines are seldom used because they require aspécial gun. • Rifles are still the prédominant infantryweapon today. Modem automatic rifles hâve twoimportant rôles. They must fire accurate singleshots,which they do very well, and then by meansof.a selector button, they must fire fullyautomatic like a machine gun. The intended purposeof this second rôle is to eliminate the need for asecondary automatic support weapon by making therifle an ail purpose weapon. In practice, however,the rifle makes a poor machine gun. Its mostobvious flaw is its small magazine, usuallÿ thirtyshots. In a situation that requires full automaticfire, each magazine is emptied so quickly that thesoldier must spend more time changing magazinesthan firing. This "down time" limits the rifle’seffect and increases the soldier's vulnerability incombat. 30 -2- 008573 A large capacity drum magazine for therifle would overcome this problem by increasing thefirepower of the rifle. Howevec, existing drummagazine technology is not compatible with existingrifle technology. A gun magazine serves as both anammunition container and as a feed device. It is,of course, an essenti-al assembly for the gun, butunlike other assemblies within the· gun, which aremechanically linked^-together so that theirfunctions are coordinated, the magazine is adétachable and separate unit. The magazine's drivemechanism, without assist from the gun, must befast enough to kee’p up with the gun cycle. Inorder to provide a large capacity magazine forautomatic rifles, such as the M-16, it is necessaryto move the mass of cartridges the requireddistance in the same time as in small capacitymagazines originally de^igned for the gun.
However, a larger weight of cartridges requires alarger force to accelerate them, and the forcerequired to move 100 cartridges in a standardmagazine design used with an M-16 would place somuch force on the cartridge in the feed positionthat it would impede or jam the weapon mechanism.
Unlike other drum magazines, the présentinvention, with 100 cartridge capacity, willadvance each cartridge into the feed position justas fast and with no greater binding force than fora conventional 30 cartridge magazine. Because ofthis and the geometry of its construction, themagazine can be used on almost any modem combatrifle without modification to the gun. It does notpreclude the use, of standard 30 shot magazines, sothe two types can bè used interchangeably. 3- 008578
Firepower is not always required ordésirable, but when it is, the combined limit ofexisting rifle and magazine technology offers nobefcter solution than a spécial support weapon or abigger army. The présent invention offers anentirely different solution. When needed, ittriples the immédiate firepower of every riflemanand reduces his vulnerability in combat.
SUMMARY OF THE INVENTION A single drum magazine of the présentinvention comprises a generally cylindrical drumwith an opening for the exit of cartridges fromwithin the drum. A spring driven rotor within thedrum carries two concentric rings of cartridges, . oriented with their axes approximately parallel to the drum axis, in a channel defined by the outer circumference of.the rotor and the int'erior of the cylindrical drum wall. The rotor engages the inner concentric ring of ca'btridges, and the width of said channel is less than the diameter of two cartridges, such that the outer concentric ring of cartridges is necessariLy offset from the cartridges in the inner ring. The cartridges in the outer ring are thereby nested in recesses formed between adjacent cartridges in the inner ringr As a resuit, when the rotor is caused to rotate, thereby forcing the inner ring of cartridges tp mpve_ around a circle, each cartridgef ** & in the outer ring of cartridges is also forced tomove by contact with a cartridge of the inner ringjust behind it with respect to the direction ofrotation. Also, since the outer ring of cartridgeshas a greater circumference than the inner ring, * . '008578 there will be gaps betweén adjacent pairs of outerring cartridges. · \ An exit channel between the rotor and the magazine exit reduces the width of the cartridge· 5 chapn.el from that' of the width of the offset doublerow of cartridges to that of a single row ofcartridges·. This réduction in width may beaccomplished by means of a cam blade which forcescartridges f.rom the. inner ring· of cartridges, as. 10 they leave the rotor, into the gaps between thecartridges of the outer ring as ail of thecartridges movê through the narrowing passage. .. I.t.should be noted that the cartridges will rollduring the transition-from double column to single 15 column and that r.olling friction‘wi11 thereby applyto ease the merging process. Thus during feeding,the cartridges are driven by the force of -the . spring and advaneed as two rings until they meetthe'c.àm blade, which. gradually forces the 20 cartridges into a single column which moves approximately twicê as fast as -the velocity of thecartridges in the rotor, and the magazine will beemptied in about a single rotation of the rotor.
When the la.st cartridge leaves the rotor 25 during feeding and enters the exit passage, a meansis provided to continue to push the last cartridge • out of the magazine. This may be accomplished by a follower arm attached to the rotor. Preferably the» e . follower arm is pivotally attached to the rotor at 30 one of its ends, and has a' pusK&ng surface at its other end, such as a dummy cartridge. The follower arm retracts within the inner circumference of the * inner ring of cartridges when the magazine isloaded and extends outward and into the exit 35 passage as the magazine empties. While the -5- 008578 follower arm is optimally designed to force ailcartridges out of the magazine, in practice anextension means may be necessary to feed thecartridge into the gun. In such case, an 5 appropriate number of dummy cartridges may either be built within the magazine or loaded intothe magazine to fill the additonal length of theextension means when the follower arm is fullyextended. 10 The magazine may be loaded by hand or machine by reversing the feeding process andintroducing cartridges into the; feed end of themagazine. As each cartridge is introduced, thepreceding cartridges will move into the magazine 15 and automatically expand into thô two concentricoffset rings of cartridges, causing the rotor torotate against the spring force until the magazineis filled to çapac'ity.
Another embodiment of the présent 20' invention utilizes twb of the drum magazines described above joïned together at their respectiveexit openings by aconnection means which directsthe cartridges exiting from each drum into a feedbox or extension located centrally between the 25 drums. This is especially désirable in the case ofà gunf such as an M-16, which normally utilizes aconventional double column box magazine. In thiscase, the cartridges exiting from ea.eh of the drumsare directed to form the two staggered· columns of . 30 cartridges in the central box. The drums areseparated far enough from the central box toaccomodate the width of the gun receiver betweenthem when the central box is fitted within the gun.This embodiment forms a unit which is more compact 35 . thah a single drum of the same cartridge capacity, -6 fits the gun more favorably with moie handling and.ground clearance, and maintains the.advantages ofthe invention as described below.
The inv.ention overcomes the dif.ficulties5 inhérent in the pr.ior artby reducing the spring force necessary to move the desired mass ofcartridges in the required time and by reducing therésultant force exerted by the cartridge to be fedinto the gun for a given spring force.. That is, 10 sinçe two rings of cartridges in the drum produce asingle row of cartri,dge’s exiting the drum, to movea new cartridge into the loading posi.tion the totalmass of cartridges need only be moved approximatelyhalf the distance that would be required in a prior 15 art drum. This allows a réduction. in the springforce by about a factor of two from what would benormally required to move the cartridges in thetime necessary to meet the cycle time of, the-automatic gun. In addition, the ef’fect of the 20 · graduai merging action from two rows to one row, and the résultant accélération of the cartridges, ' is·to reduce the force on a cartridge exiting thedrum from the force which the spring applies tothecartridges within the magazine..····.-T.his ef-fe.çt also- 25' hel.ps to· màke possible the’ high .s'péed feeding. of alarger volume of cartridges w.ithoùt adverseïy-·affect.ing the gun loading.mechanism.
Some box magazines hâve been designedwhich incorporate a réduction.of a double column of 30 cartridges to a single column. However, such box magazines do not hâve the gap between cartridges atthe start of the transition from a double row to asingle row, and, therefore, tend to bind, which .inhibits smooth accélération of the cartridges. -7- 00578
The simplicity of fche· design of theinternai mechanism of the invention lends itself toless costly manufacturing since the magazine maybe constructedwith modem production methods-and' 5 matériels, such as by métal stampings or plasticmolds. Such a magazine may be lightweight anddisposable, and such features will be especiallybénéficiai for military use.
In summary, it is an object of this10 invention to provide-.a magazine that will hold a large number of ammunition rounds, which mayfunction on any unmodified magazine· gun or rifleand which, therefore, does not require a spécialgun for its operation. 15 it is a further object'of this invention to provide a magazine for an’autômatic gun or riflewhich can feed a large number ôf cartridges to theweapon without retarding the weapon mechanism. 'It is a ^till further object of this 20 invention to provide a large c'apacitÿ magazinewhich is simple in design, economical inconstruction, lightweight and compact.
These and other objects and advantageswill appear from the'following description with 25 reference to.the drawings.
Fig. 1 is a perspective view of anautômatic rifle with a double drum magazineattached thereto.
Fig. 2 is a perspective view of a doubledrum magazine. . 30 -8- «08578
Fig. 3 is a cross-sectional view of a double drum magazine embodiment ;of the présent invention, fully unloaded.
Fig. 4 is the magazine of Fig. 3 fully 5 loaded with cartridges.
Fig. 5 is a section taken along the lineV-V of Fig. 4. . ' ’
Fig. 6 'is an exploded view of theinternai parts of the magazine and a portion of the 10 drum walls,' some of which are in partial orcomplété cross-section»
Fig. 7 is a perspective view of theinternai parts-of the drum.
Fig. 8 is a cross-sectional view of a15 single drum magazine embodiment of the présent invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS -
The preferred embodiments are nowdescribéd with reference to the drawings, in which 20 like numbers indicate like parts throughout theviews.
Fig. 1 shows a double drum magazine 10attached to an automatic rifle 11, such as an M-16.Fig. 2 shows the doub.lé drum magazine 10 which 25 includes two drum portions 12 connected together byconnection means 13, and a cartridge feed extension14 attached to said connection means. It can beseen that extension 14 is of the double row typeand is adapt.ed to the shape and dimensions of at 30 least the portion of the standard box clip whichmates with the rifle.
Fig. 3 shows in detail a double drumembodiment of the présent invention. Each drum -9- portion 12 of the magazine is essentially anidentical mirror-image of the other. Each drum hasa..central shaft.or axel 15 upon which rotate therotors. It wilï be seen below that the rotor · 5 comprises two wheels. The front wheel 16 is seen in Fig. 3. Each wheel has teeth 18 which provide apartial arc between each pair of teeth within whicha cartridge may be seated. The· magazine has agenerally cylindrical wall 19 concentric with the 10 circumference of the rotor wheels. A space 20 isprovided between the rotors and the inside o.f thedrum which forms a channel around the circumferenceof the rotor. This channel .is optimally of a widthjust sufficient to hold two offset concentric rings 15 of cartridges.. Fig. 4 shows the'magazine of Fig. 3fully loaded with cartridges and shows the twoconcentric rings of cartridges within the channelspace 20. The cartridges 21 in the inner ring‘ofcartridges are located in the spaces between' the 20 teeth of the rotor wheels and the cartridges 22 inthe outer ring are each located in a recess 23formed between two adjacent cartridges in the innerring.
With further reference to both Figs. 3 25 and 4, it is seen that a cam blade 24 is provided which gradually reduces the width of the channel 20from that of the two offset rows of cartridges atthe rotors to a single row of cartridges at theexit 25 from each drum portion 12. The connection 30 26 between the two drum portions 12 directs the two single cartridge rows from each of the drumportions towards one outlet 27’ which is only wideenough' to allow the two rows of cartridges to passthrough if they are staggered. An extension 28 is 35 attached to the connection 26 which carries the two -10- ÙO85'/8 staggered rows of cartrïdges to a standard double lip feed throat 29.
The motion of the cartrïdges out of themagazine is caused by coiled springs 30 located atthe center of each drum portion. Each spring istensioned between oa tab extension 31 of the camblade 24 and a connection 32 to the rotor wheels,thereby forcing the rotors to turn in the directionthat will move the cartrïdges into the cam area andout of the drum. Thus, it can be seen that as thelead cartridge 33 is removed from the feed throat29 the spring force on the rotors will cause therotors to rotate and ail of the cartrïdges to movein the direction of the feed throat until the topcartridge 34 from the other staggered row isstopped by the lip of the feed throat, A follower arm 35 is attached to a pivot36 on each rotor. As the last cartridge 37 on therotor is cammed away from the rotor teeth by thecam blade 24, the follower arm 35 continues totransfer the force of the spring to the lastcartridge to cause the cartrïdges to-continue tomove out of the magazine as cartrïdges are removedfrom the feed throat. The follower arm is shapedto fit within the inner ring of cartrïdges when themagazine if fully loaded. The push end of thefollower arm has a dummy cartridge 38 attachedthereto which occupies a spacë in the outer ring ofcartrirdges. As the dummy cartridge 38 enters thearea of the cam blade 24 when the magazine is beingunloaded, it naturally moves toward the exitpassage of the drum portion, which causes thefollower arm 35 t-o swing outward and into the exitpassage. As can be seen in Fig. 3, the followerarms 35 are of sufficient length to push the 11- 008578 cartridges out of the drum, through the connection 26 and the outlet 27. However, the follower arm 35 does not extend into the extension 28, and as seen in Fig. 3, it is necessary that this space be 5 filled with cartridges, which may be dummy cartridges. Even with such dummy cartridges 39,the number' of which is dépendent on the length ofthe extension 28, this embodiment of the magazineis capable of carrying and delivering one-hundred 10 rounds to a weapon. A link 40 is provided betweenthe dummy cartridge that is the lead cartridge whenthe magazine is completely unloaded and thecartridge in its row immediately behind it, toprevent the weapon from loading the dummy cartridge 15 . and to indicate that the magazine is empty.
The magazine may be loaded by inserting cartridges into the feed throat 29. Each time acartridge is loaded the cartridges within theextension 28 will be pushed downward toward the 20 dividing point 41 in the connection, which . naturally causes the two staggered rows to be split and directed into each of the drums. Duringloading the follower arm dummy cartridge 38 isnaturally caused to be pushed to a position in the 25 outer ring since the angle of the force applied tothe dummy cartridge,38 causes it to rotate outwardon its arc of travel. The succeeding cartridgesentering 'the drum will naturally alternate movinginto the inner ring or outer ring of cartridges due 30 to the position of the preceding cartridge. Theloading of cartridges will cause the rotor wheels16 to tu’rn against the spring force, first bythe' force applied to the follower arm, and after -the cartridges in the inner ring begin to be 35 located within the teeth of the rotor, by the force applied'directly to the rotor. Cartridges may beloaded until the rotors make a. complété révolutionand the<;cartridge end of the follower. arm cornesinto contact with the back of the cam blade 24. 5 With reference to Figs. 4 and 5, it is seen that as the c.artridges enter the cam areaduring unloading the cam blade 24 squeezes the tworings of cartridges into one row, By reference tothe right cam blade 24 in Fig. 5, it is seen that- 10 the cam blade is generally centrally located between the ends of the cartridges so that eachcartridge from the inner ring is cammed into.thespace between adjacent cartridges in the outér ringby the relatively thin cam blade 2.4 as a fulcrum. 15 Since cartridges may be tapered,*the thin cam bladeacts as a fulcrum point contact allowing-either endof the cartridge to go deeper. into the .path of the
- I • outer ring as room allows so that any slack at thefront or rear of the single column is taken up. 20 Furthermore, as seen in Fig. 5/ the drums^l2 aretilted slightly forward, as is thé central box.extension. 28, to compensate for the açcumûlaCed.angles of taper of the cartridges in the cam area,connection and extension. 25 Cartridges ro-11 .during .the ^transition • . * * * " ’ O . · · . . · from'double column to single column in thé cam·area, and, therefore, rolling friction applies, notslidîng friction. However, in order to hâve thecartridges cam smoot'hly the camming should be 30 graduai. In this embodiment, an angle of about 15degrees is made between the cam blade 24 and thetangential portion 42 of the inside faceof the drum, which’ is about the maximum angle thatwill cam smoothly. Also, for smooth camming, it is 35 important for the camming’process to begin before -13- the gap 43 between two adjacent cartridges in the outer ring begins to close, which will occur wheneach cartridge in the outer ring reaches thetangential drum portion 42. In the embodimentshown 'in Fig. 4, the angle 44 formed betweenadjacent cartridges in either the inner or outerring is 15 degrees, and therefore the angle 45between a cartridge in the inner ring and acartridge in the outer ring is 7-1/2 degrees.Therefore, the.cam blade should begin camming acartridge in the inner ring at least 7-1/2 degreesbefore the beginning of the tangential portion 42of the drum. In general, the angle between the cam blade 24 and the tangential portion 42 of the drum « may be chosen as being about equal to the angle 44formed between adjacent cartridges in the innerring.
It is also important that the'teeth 18 ofthe rotors 16, 17 do not extend so far that theywill impede an inner ring cartridge from movingforward in the cam area as necessarily caused bythe camming of cartridges behind it.
Fig. 5 al-so shows in greater detail thefront wheel 16 and rear wheel 17 of the rotor ontheir axel 15. The spring 30 is seen to be twoinverse coiled spring portions 46, 47, which may beformed with a single wire with the center of thespring anchored to the cam blade.
Fig. 6 is an exploded drawing of theéléments inside the drum, showing the parts ingreater detail. The part numbers are the same aspreviously used, with a eut away portion of thefront face 48 and rear face 49 of the drum shownthrough which the screws 50 and washers 51 attachto the axel 15. Spacers 52 are provided to support -14- the spring 30 and. reduce thé friction of rotation of the wheels 16, 17. The caffi blade 24 is mounted around the axel and is anchored to the drum by means of a screw 53. ... » ·.·. 5 The follower arm 35 is seen to hâve a ' U-shape with cylindrical extensions 54 whiich fit · into the pivot holes 36 of the front and rear.wheels. The follower arm dummy cartridge comprises an apprbpriately shaped head 55 and tail 56 portion * · " ’ · . l ' 10 attached to a pi.n 57 through a hole' 58 throug.h the • push end oï' follower' "atrïti. The h*ole -’5'â‘ i«so ; . s.iï§lvtly lea»rgfe.r· thah' th%®pin and‘tapered outward at both openings to allow- thé dummy cartridge torotate and tilt as it moves through the cam area, 15· . The U-shaped opening of the follower arm is necessary to âllow the arm to fit around the camblade 24 both when fully. loa.ded (see Fig. 4) andfully unloaded·(see Fig. 3). Fig. 7 is a perspective view w.hich more clear.ly shows the 20' interaction of the follower arm '35 and the cam• blade 24. A portion of the push end of the follower arm is eut away 59' where the follower arm will corne into 'contact with. the cam blade when thedrum is fully loaded, to provid..e room for an 25 .additional cartridge to be loaded into the ". magazine.
Fig. 8. shows a single drum embodiment 112of the présent· invent ion.· The· parts and. opérât ion of this embodiment are essent.iaily the same as 30 described above, with a rotor 116 on an.axel 115 moving an inner ring of cartridges 121.and an outer ring of cartridges 122 around the drum 112 and directing the cartridges 121 °and 122 into a single row'by means of.’ the cam blade 124 as the lead» 35 cartridges 133-are removed. A .follower arm 135 is . -15- utilized to push out the last cartridge as described for the double drum configuration..However, no connection·(subh as 26) is required andthe extension 128 carries a single row of cartridges.
The màgazine of the présent invention maybe made of any suitable materials, such as. metalsand plastics. Ideally, the drums and connectionswill be formed as a one piece plastic in a.moldingprocess, with as many other parts as appropriâtemade of plastic, to produce the lightest possibleproduct consistent with durability and reliableoperation. Any implémentation of the invention .should be appropriately sized based on thedimensions of the cartridges to be stored therein.
While the invention has been·described indetail with particular reference to the preferredembodiments thereof, it will be understood thatvariations and· modifications çan be. ef'fected- withihthe spirit and . scope of the invention as previouslydescribed and as defined by the claims.

Claims (19)

16 05 10 15 20 25 WHAT IS CLAIMED IS; 0965 ? π
1. A drum maqazine for successiveïy feeding apluralîty of cartridqes to a firearm, comprisinq; a) a drum shaped housinq means havxng a cartridgeexi.t openinq extending from the side of saidhousing means; b) rotational cartridge carrying means with.j.n said housing means wbicb defines-acartridqe space, between said cartridgecarrying means and the inner wall of saidbousing means, for two offset concentric ringsof cartridges, wherein each of the cartridqesof the outer concentric ring are nested in therecess formed bv two adjacent cartridges inthe inner concentric ring of cartridges andare urged to revolve around said drum bv therearward of said adjacent cartridges in the .inner ring of cartridges, said rotationalcartridge carrying means cômprising means forindividually defining the positions of eachcartridge of .the inner r.ing of cartridges andfor individually urging each'of saidcartridges of the inner ring of cartridges to•revolve around’sàid drum as said cartridge-canrving mearis.rotâtes;·and ·-'. ...· ?· c) cam’ means with.in-'said'-hQus-rrig'.méém^iâ^.fi'ïÎià^.·:.with said housing means, a· passage .from ther. cartridge· spacè to the éxit opening? ô£/£âid<V(/’'housing means for urginq two offset concentric . rlnqs of cartridqes aiternately toaether-intoa sinqlé row as said cartridqes are moved outof said magazine. 30 17 008578 .2.· ^he drum magazine of Claim 1, further it *· comprising: d) extension means assocîated with said housingmeans and defining a cartridge feeding cbannel 05 in communication with the exit opening of said housing means; and e) drive means to rotationally urge saidcartridge carrying means in the directionwhich will move cartridges within said drum 10 magazine .into the passage defined by said cam means and said housing means.
3. The drum magazine of Claim 1, wherein saidmeans for indiv.idually defining the positions of 15 the inner ring of cartridges and for individually urging the cartridges comprises teeth on the outercircumference of said rotational. cartridgescarrying means. '20 4. The drum magazine of Claim 1, wherein said drum shaped housing means comprises a front faceand a rear face and wherein said cam meanscomprises a blade connecte# to said housing meanshaving an edge which defines the passage with said 25 · housing means,. said blade located between the front and rear faces of said housing means such . that. the edge of said blade cornés into.contact:-with'a cartridge' êxiting from the inner ring at a. point significantly "awaÿ from/eithe.r end of the.' 30 · cartridge. . .
5. The drum magazine, of Claini· .4, wherein theblade of said cam means forms one side of an exitpassage having an angle of 15 degrees or less with 35 respect to the éther side of the exit passage. 18 0.0 8 5 78 05' 10 15 20 25 ·. 30 .
6. The drum magazine of Clairn.4, wherein theblade of the said cam means forifts one side of anexit passage having an angle equal to the angle .between the cartridges in the inner ring withrespect to the other side of the exit passage. · ·
7. The drum magazine of. Clairn 4, wherein theblade of said cam means in tangential to the innercircumference of the inner ring of cartridges, andthe inner face of said .housing means at'the exitpassage is tangential to the outer circumferenceof the outer ring of cartridges.
8. The drum magazine of Clairn 7, wherein theblade of said cam means is posit-ioned with respectto the tangential portion of the inner face ofsaid housing means such that each cartridge of theinner ring reaches said cam means prior to eitherof the respective adjacent cartridges of thie outer.ring reaching the tangential portion of the innerface of said housing means., thereby caùsing eaCh 'cartridge of the inner ring to be.cammed into thegap between the adjacent Cartridges of the buterring before the gap would begin to. close.
9. A magazine for succès s i v.ëly feeding a·.,pluralitÿ of cartridges .to a firearm,.comprising; a) two drum shaped housing means, each having a 'cartr.idgë exit ôpening êxtending frôm the sideof said housing means;· · · b) · connecting meanè..for jcining. each; of . said housing means at' the exit. openings of ëach ofsaid housing means, said connecting means ·having passages within for receiving singlerows of cartridges exiting from the exitopenings of each of said housing means"andmerging the two rows of cartridges into astaggered double row of cartridges as theyexit 'said connecting means? 35 19 008578 c) > extension means extendibq from said connectinq means for placement in round-feedi.nq relation1 ' witb a firearm, said extension havïng a round-feedinq openinq and havinq a passage 05 ' from said connectinq means to the ( round-feeding openinq approximately tbe widtb of a staqqered double row of cartridqes; d) ' rotational cartridge carryinq means within said housing means wbich defines a cartridge 10 spàce, between said cartridqe carrving means and tbe inner wall of said housing means, fortwo offset concentric rings of cartridges,wherein each of tbe cartridqes of the outerconcentric ring are nested in the recess 15 formed by tw.o adiacent cartridges in tbe inner concentric ring of cartridqes and are urged torevolve around said drum by tbe rearward ofsaid adiacent cartridges in tbe inner ring ofcartridqes, said rotational cartridge carrying 20 means comprising means for individually defining ;tbe positions.of each· cartridge of.the inner rinq of cartridges and .forindividually urging each of said cartridgesof tbe inner rinq of cartridges to revolve 25 around said drum as said cartridge carrying meàns rotâtes; and' e) . cam means within said housing means defining, with said housing means, a passage from tbecartridge space to, ex.it openi.ng of said 30 housing means for urging two offset concentric rings of cartridges alternatelv together intoa single row as said cartridqes are moved outof said magazine. ·» - 20 008578 05 10 15 20 25 30
10. The drum magazine of Claim 9, whereln saidmeans for individually defininq the positions oftbe inner rinq of cartridges and for individuallyurging the cartrldqes comprises teeth on the outercircumference of the said rotational cartridgescarrying means.
11. The drum magazine of Claim 10, which furthercomprises a spring to rotationallv urge saidcarriage carrving means in the direction whichwill move cartridges within said drum magazineinto the passage defined by said cam means andsaid housirig means.
12. The drum magazine of Claim 9, wherein saiddrum shaped housing means comprises a front faceand a rear face and wherein said cam meanscomprises a blade connected to said housing meanshaving an edge which defines the passage with saidhousing means, said blade located between thefront and rear faces of said housing means suchthat tbe edge of said blade cornes into contactwith a cartridge exiting from the inner ring at apoint siqnificantly away from either end of thecartridge.
13. The drum magazine of Claim 12, wherein theblade of said cam means forms one side of an exitpassage having an anqle of 15 deqrees or less withrespect to the other side of the exit passage.
14. The drum magazine of Claim 12, wherein theblade of said cam means forms one side of an exitpassage havinq an angle equal to the angle betweenthe cartrldqes in the inner ring with respect tothe other side of the exit passage. • 35 - 21 - ι 0085 R 05 10 15 20 25 30
15. The drum magazine of Claim 12, wherein theblade of said cam means . is tangential to the innercircumference of the inner ring of cartridqes, andthe inner face of said housing means at the exitpassage is tangentjal to the outer circumferenceof the outer ring of cartridges. ?
16. The drum magazine of Claim 15, wherein theblade of said cam means is positioned with respectto the tangential portion of the inner face ofsaid housing means sucb that each cartridge of theinner ring reaches said cam means prior to eitherof the respective adjacent cartridges of the outerring reaching the tangential portion of the innerface o.f said housing means, thereby causing eachcartridge of the inner ring to be cammed into thegap between the adjacent cartridges of the outerring before the gap would begin to close.
17. A method of storing cartridges and feedingcartridges into a firearm comprising the steps of: a) storing said cartridges in two staggeredconcentric rings within a cylindrical drum,such that a cartridge of the outer concentricring is nested in each of the recesses formedby twô adjacent cartridges of the inner ringof cartridges; b) individually urg.ing each of the cartridges inthe inner ring of cartridges such that saidstaggered rings of cartridges revolve togetheraround the cylindrical drum; c) directing the leading end of the said twostaggered rinqs of cartridges towards an exitof said cylindrical drum; and d) camming said two staggered rings of cartridgestogether into a single row of cartridges assaid cartridges exit said cylindrical drum. 35 -. 22 098578
18. Tbe method Claim 17, wherein the step ofcamming said two.staggered. rows is initiated fôreacb cartridge of tbe inner row prior to the pointwhere the two adjacent cartridges in the outer row 05 ' leave the circle originally formed by said outer ring, so that each cartridge of the inner ring iscammed into the gap bet'ween the adjacent cartridgeof the. outer ring before the gap would begin toclose. 10
19. The method of Claim 17, which furthercomprises'the step of directing said cartridgesexiting said cylindrical drum into the firearm.
20. The method of Claim 19, which fürther comprises the steps of: a) directing the single rows of cartridgesexiting from two of said cylindrica] drums sothat thev reform as staggered rows of 20 cartridges prior to feeding said cartridges into a firearm? b) directing said two staggered rows ofcartridges into the firearm; and c) repeatedly lifting the leading cartridge of 25 said two staggered rows of cartridges into the feed position of a firearm.
21. The method of Claim 17, wberein the cartridgesexiting said cylindrical drum move about twice the 30 distance as the cartridges within said cylindrical drum.
OA59088A 1985-07-24 1987-03-17 Drum Magazine. OA8578A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US06/759,058 US4658700A (en) 1985-07-24 1985-07-24 Drum magazine

Publications (2)

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OA8578A true OA8578A (en) 1988-09-30
OA08578A OA08578A (en) 1988-09-30



Family Applications (1)

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EP (1) EP0210713B1 (en)
JP (1) JPH0481719B2 (en)
KR (1) KR910003038B1 (en)
CN (1) CN1005045B (en)
AT (1) AT39570T (en)
AU (1) AU568788B2 (en)
BR (1) BR8606808A (en)
CA (1) CA1234006A (en)
CU (1) CU21942A3 (en)
DD (1) DD248646A5 (en)
DE (2) DE3661577D1 (en)
DK (1) DK147387A (en)
EG (1) EG17729A (en)
ES (1) ES2000732A6 (en)
FI (1) FI91322C (en)
GB (1) GB2187269B (en)
GR (1) GR861928B (en)
HK (1) HK83792A (en)
HU (1) HUT44330A (en)
IE (1) IE57249B1 (en)
IL (1) IL78211D0 (en)
MW (1) MW1687A1 (en)
MX (1) MX162988B (en)
NO (1) NO171654C (en)
OA (1) OA8578A (en)
PH (1) PH22511A (en)
SG (1) SG792G (en)
SU (1) SU1662358A3 (en)
TR (1) TR23112A (en)
WO (1) WO1987000614A1 (en)
ZA (2) ZA8605457B (en)
ZW (1) ZW13986A1 (en)

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US7441491B2 (en) * 2005-11-14 2008-10-28 Annatac Industries, Incorporated Drum magazine for firearm
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US20100083818A1 (en) * 2008-10-02 2010-04-08 David Joe Harris Firearm adapter for am180 .22 caliber cartridge drums
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KR101220503B1 (en) * 2012-03-13 2013-01-10 노태종 Drum type magazine
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US8839706B1 (en) * 2013-03-05 2014-09-23 Real Action Paintball (RAPY) Drum magazine for projectiles
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CN108088305B (en) * 2017-12-11 2019-08-16 康郦 Large diameter automatic gun is fast automatic to select bullet method
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US10634449B2 (en) 2018-01-19 2020-04-28 United Tactical Systems, Llc Air actuated magazine for projectile loader
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Also Published As

Publication number Publication date
JPS62501579A (en) 1987-06-25
BR8606808A (en) 1987-10-13
OA08578A (en) 1988-09-30
DE3661577D1 (en) 1989-02-02
JPH0481719B2 (en) 1992-12-24
FI91322B (en) 1994-02-28
AT39570T (en) 1989-01-15
AU5690586A (en) 1987-02-10
GB2187269B (en) 1989-01-05
FI871092A0 (en) 1987-03-12
ZA8605457B (en) 1987-03-25
FI91322C (en) 1994-06-10
NO871191D0 (en) 1987-03-23
FI871092A (en) 1987-03-12
ZW13986A1 (en) 1986-12-17
IL78211D0 (en) 1986-07-31
US4658700A (en) 1987-04-21
GB2187269A (en) 1987-09-03
CA1234006A (en) 1988-03-15
IE861950L (en) 1987-01-24
CN1005045B (en) 1989-08-23
SG792G (en) 1992-03-20
KR880700238A (en) 1988-02-20
EP0210713A1 (en) 1987-02-04
CU21942A3 (en) 1996-10-05
GB8703955D0 (en) 1987-03-25
DD248646A5 (en) 1987-08-12
AU568788B2 (en) 1988-01-07
CN86105123A (en) 1987-06-17
EG17729A (en) 1991-06-30
WO1987000614A1 (en) 1987-01-29
DK147387D0 (en) 1987-03-23
DE210713T1 (en) 1987-11-05
GR861928B (en) 1986-11-25
MX162988B (en) 1991-07-30
HK83792A (en) 1992-11-06
DK147387A (en) 1987-03-23
IE57249B1 (en) 1992-06-17
TR23112A (en) 1989-01-01
SU1662358A3 (en) 1991-07-07
PH22511A (en) 1988-09-12
NO171654B (en) 1993-01-04
KR910003038B1 (en) 1991-05-17
EP0210713B1 (en) 1988-12-28
CA1234006A1 (en)
NO171654C (en) 1993-04-14
ES2000732A6 (en) 1988-03-16
HUT44330A (en) 1988-02-29
MW1687A1 (en) 1988-08-10
ZA865457B (en) 1987-03-25
FI871092D0 (en)

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