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Publication numberUS3345771 A
Publication typeGrant
Publication dateOct 10, 1967
Filing dateJan 7, 1966
Priority dateJan 7, 1966
Publication numberUS 3345771 A, US 3345771A, US-A-3345771, US3345771 A, US3345771A
InventorsSilsby Stanley D
Original AssigneeSilsby Stanley D
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
High capacity magazine and cooperating firearm structure
US 3345771 A
Abstract  available in
Images(4)
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Claims  available in
Description  (OCR text may contain errors)

Oct. 10, 1967 Filed Jan. 7, 1966 Eig i S. D. SILSBY HIGH CAPACITY M AGAZ INE AND COOPERATING FIREARM S TRUCTURE 4 Sheets-Sheet l ATTORNEYS 3,345,771 HIGH CAPACITY MAGAZINE AND COOP- ERATING FIREARM STRUCTURE Stanley D. Silsby, Granby, Mass., assignor to the United States of America as represented by the Secretary of the Army Filed Jan. 7, 1966, Ser. No. 519,398 6 Claims. (CI. 42-18) ABSTRACT F THE DISCLOSURE It is one object of this invention to provide for a firearm in which cartridges are extracted longitudinally from a magazine by a reciprocal bolt, a magazine unit consisting of two magazines each adapted for holding a double stack of cartridges with the two magazines positioned side-by-side and separated by a partition with a pivotal divider arranged to permit radial loading of the cartridges into the two magazines through a common mouth.

It is a further object of this invention to provide cooperating firearm structure fcr such magazine unit arranged to hold the cartridges in one of the magazines depressed out of contact by the bolt until the last cartridge in the other magazine is removed therefrom.

The specific nature of the invention as well as other objects and advantages thereof will clearly appear from a description of a preferred embodiment as shown in the accompanying drawings which:

FIG. 1 is a fragmentary, partially cross-sectioned view of a firearm with the magazine unit and cooperating structure of this invention mounted therein;

FIG. 2 is a view taken along line 2-2 of FIG. 1;

FIG. 3 is a view taken along line 3-3 of FIG. 1 with the hammer removed;

FIG. 4 is an enlarged fragmentary view similar to FIG. 3;

FIG. 5 is a view similar to FIG. 4 but shows the actuator displaced to the disengaged position and held with the depressor in release position;

FIG. 6 is a view taken along line 6-6 of FIG. 4;

FIG. 7 is a view taken along line 7-7 of FIG. 4;

FIG. 8 is a view taken along line 8-8 of FIG. 6;

FIG. 9 is a view taken along line 9-9 of FIG. 6 and shows the cartridges in the primary magazine ready for extraction by the bolt and the cartridges in the reserve magazine held out of contact by the bolt through the switch device;

FIG. 10 is a view similar to FIG. 9 but shows the switch device actuated to release the cartridges in the reserve magazine for pickup by the bolt;

FIG. 11 is a fragmentary view of the rear end of the magazine showing the cooperation of the pivotal divider with the lips of the magazine unit as cartridges are loaded thereinto;

FIG. 12 is a perspective view of the actuator; and

FIG. 13 is a perspective view of the depressor.

Shown in the figures is a firearm 14 which includes a receiver 16 with a barrel 18 extending forwardly therenited States Patent Office 3,345,771 Patented Get. 10, 1967 from. A bolt 20 with an integral operating rod 22 is mounted in receiver 16 for reciprocation between a forward battery position and a rearward recoil position.

Extending upwardly into receiver 16 is a well 24 which receives a magazine unit 26 for holding a supply of cartridges 28 and for successively positioning the cartridges for pickup by bolt 20 during travel to battery position and transfer thereby into barrel 18 for discharge.

Magazine unit 26 includes a case 30 preferably fabricated from a clear plastic material so that the load of cartridges 28 therein may be readily checked visually. Case 39 includes a right hand side 32 the inside of which curves upwardly and inwardly at the top to form a lip 34 and a left hand side 36 is similarly provided with a lip 38. Lips 34 and 38 are spaced a distance greater than the diameter of cartridges 28 to form a mouth 40' into which the cartridges are successively positioned, as hereinafter described, for pickup by bolt 20. Case 30 also includes a front end 42 and :a rear end 44.

A partition 46 divides case 30 into a primary magazine 48, formed between the partition and right hand side 32, and a similar reserve magazine formed between the partition and left hand side 36. Each of the magazines 48 and 50 is adapted to hold a double stack of cartridges 28 in staggered arrangement, as shown in FIG. 2. Partition 46 includes a fixed wall 52 and a divider 54 which is an upper extension thereof and which is mounted for pivotal displacement in alignment with the wall so that cartridges 28 may be inserted radially into primary magazine 48 and reserve magazine 50, as hereinafter described, to facilitate the loading of magazine unit 26.

Divider 54 is pivotally mounted in case 30' by means of a tongue 55 which extends forwardly from the front end thereof for reception by a mating hole 56 in front end 42. A tang 57 extends rearwardly from the rear end of divider 54 for reception by a vertical slot 58 formed in rear end 44 to permit limited vertical displacement of the rear end of the divider. Extending downwardly from the bottom end of slot 58 is a bore 60 which mounts a spring biased plunger 62 that :acts against tang 57 to bias the rear end of divider 54 upwardly to its normal position.

Slidingly mounted in reserve magazine 50' is a follower 64 which is pressed upwardly by a spring 66 to bias cartridges 28 in such magazine upwardly therein. A follower 67 is similarly mounted in primary magazine 48 and is biased upwardly therein by a spring 69. Follower 67 is provided with a shaft 68 which extends rearwardly therefrom through a vertical clearance 71 in rear end 44 and such clearance is designed to permit free movement of the follower as cartridges 28 are extracted from primary magazine 48 and for continued displacement to an overtravel position after the last one of the cartridges is removed.

The distance between the top edge of divider 54 and each lip 34 and 38 is less than the large diameter of cartridge 28, as shown in FIG. 10, so that the cartridges in primary magazine 48 and reserve magazine 50 are prevented fiom being pressed upwardly out of magazine unit 26 but are free to be extracted longitudinally therefrom by bolt 20 during travel to battery position. However, cartridges 28 may be loaded freely into primary magazine 48 and reserve magazine 50* by successively placing the cartridges against the top edge of divider 54 and the proper lip 34 or 38 and pressing downwardly as shown in FIG. 11. This pressure pivots divider 54 downwardly until the space between the top of the divider and the related lip 34 or 38 is increased .to where cartridge 28 can pass thereby. When cartridge 28 ha passed thereby, divider 54 snaps upwardly under the urging of spring biased plunger 62 to its normal position to retain the cartridge in the particular magazine 48 or 50.

When magazine unit 26 is installed in well 24, cartridges 28 in reserve magazine 50 are pressed downwardly as shown in FIG. 9 away from contact by bolt 20 by means of a switch device 70 until the cartridges in primary magazine 48 are entirely exhausted, whereupon the cartridges in the reserve magazine are automatically released as hereinafter described for pickup by bolt 20.

Switch device 70 is mounted on a trigger housing 72 in well 24 so as to be cooperable with shaft 68. Switch device 70 includes a depressor 74 and an actuator 76 both of which are pivotally mounted on a pin 78 which extends forwardly into well 24 from the rear end of trigger housing 72. Thus, depressor 74 and actuator 76 ar each pivotal in a transverse plane, respective to the long axis of receiver 16, between an inner retaining position and an outward release position. Depressor 74 includes an arm 80, essentially of inverse L configuration, which extends upwardly from pin 78 between the rear end of well 24 and rear end 44 of case 30 and then forwardly between the left hand side 36 of the case and the left side of the well. Extending inwardly from the free end of arm 80 is a retainer tab 82 which is receivable by a notch 84 in the top end of the left hand side 36 of case 30 when depressor 74 is in the retaining position and magazine unit 26 is fully installed in well 24. Retainer tab 82 extends sufiiciently into reserve magazine 50 so as to contact the leading cartridge 28 therein when depressor 74 is in its retaining position. Retainer tab 82 is so spaced radially from pin 78 that as magazine unit 26 is inserted into well 24 the retainer tab contacts the leading cartridge 28 and when the magazine unit is fully installed the leading cartridge is pressed downwardly away from contact by bolt 20 during reciprocation thereof as shown in FIGS. 2 and 9. When depressor 74 is pivoted to its release position, retainer tab 82 is displaced outside of case 30 so that cartridges 28 in reserve magazine 50 are released thereby and free to be pressed upwardly to where the leading one of the cartridges is positioned in mouth 40 between divider 54 and lip 38 ready for pickup by bolt 20 as shown in FIG. 10. Depressor 74 is biased to its retaining position by a spring 86.

Actuator 76 is mounted on pin 78 outside of depressor 74 and is mounted on the pin by means of an orifice 88 which is elongated along the long axis of the actuator so that the actuator is displaceable translationally as well as pivotally on the pin. Provided on the inside of actuator 76 above orifice 88 is a slot 90 which is symmetrical to the long axis thereof and such slot is terminated at the bottom end by a tongue 92 which extends inwardly from the actuator. Slot 90 slidingly receives a flange 94 which extends outwardly from depressor 74, whereby actuator 76 is prevented from moving pivotally relative to depressor 74 but is free to move translationally respective thereto between an upper engaging and a lower disengaged position. A spring 96 is positioned between tongue 92 and flange 94 for biasing actuator 76 downwardly to the disengaged position.

Extending from the right side of actuator 76 is an arm 98 which is contactable by shaft 68 during overtravel of follower 67 so that the actuator is displaced thereby to the engaging position when such follower is moved upwardly by spring 69 to its overtravel position after the last cartridge 28 in primary magazine 48 is removed therefrom by bolt 20. Extending integrally upward from the top of actuator 76 is a finger 100 which, when the actuator is in its engaging position, is contactable by a cam surface 102 on operation rod 22 during rearward travel of bolt 20. Thus, during the rearward stroke of bolt 20 to the recoil position, after the last cartridge 28 is picked up from primary magazine 48 and fired and actuator 76 is displaced by shaft 68 to its engaging position as hereinbefore described, the actuator is pivoted to its release position by contact of finger 100 with cam surface 102 as the bolt moves in recoil. Through the engagement of flange 94 with slot 90, depressor 74 is simultaneously pivoted to its release position so that cartridges 28 in reserve magazine 50 are released and the leading one positioned in mouth 40 for pickup by bolt 20 during the following forward stroke thereof to battery position. When actuator 76 is displaced to its release position, arm 98 is slipped off shaft 68, whereby the actuator is free to be displaced by spring 96 to its disengaged position. Arm 98 is terminated by an end 104 which is contactable by shaft 68 when, as shown in FIG. 5 follower 67 is in its overtravel position and actuator 76 is in its disengaged position. Thus, actuator 76, and consequently depressor 74 are blocked against displacement from their release positions.

Although a particular embodiment of the invention has been described in detail herein, it is evident that many variations may be devised within the spirit and scope thereof and the following claims are intended to include such variations.

I claim:

1. In a firearm having a receiver and a bolt with an operating rod reciprocal between a forward battery position and a rearward recoil position, a magazine unit for cartridges, said magazine including a case having a pair of sides, a partition dividing said case to form a primary magazine between said partition and one of said sides and a reserve magazine between said partition and the opposite one of said sides, each said primary and reserve magazines being adapted to hold a double stack of the cartridges in staggered arrangement, a mouth for receiving the cartridges'from said primary and reserve magazines in position for longitudinal extraction by the bolt during travel to the battery position, a pair of lips respectively formed in said pair of sides at said month, said lips being spaced a distance greater than the diameter of the cartridges, a divider section of said partition arranged in cooperation with said lips for positioning a leading one of the cartridges from one of said primary and reserve magazines at said mouth for extraction by the bolt, and means for displaceably mounting said divider so as to permit radial insertion of the cartridges between said divider and each of said lips into said primary and reserve magazines.

2. In a firearm having a receiver and bolt with an operating rod disposed for reciprocation between a forward battery position and a rearward recoil position, a magazine unit for cartridges, said magazine unit including a case having a pair of sides, a partition dividing said case to form a primary magazine between said partition and one of said sides and a reserve magazine between said partition and the opposite one of said sides, each said primary and reserve magazines being adapted to hold a double stack of the cartridges in staggered arrangement, a mouth for receiving the cartridges from said primary and reserve magazines in position for longitudinal extraction by the bolt during travel to the battery position, a pair of lips respectively formed in said pair of sides at said mouth, a divider section of said partition arranged in cooperation with said lips for positioning a leading one of the cartridges from one of said primary and reserve magazines at said mouth for extraction by the bolt, means for mounting said divider for pivotal displacement in alignment with a fixed section of said partition, a spring biased plunger acting against said divider for biasing said divider from a depressed to a normal position, and said divider being so arranged in cooperation with said lips that when said divider is in the normal position the cartridges are held against radial displacement from said magazine unit by contact of the leading cartridge in each said primary and reserve magazines with said divider and the related one of said lips and when said divider is in the depressed position the cartridges are insertable radially thereby into said primary and reserve magazines.

3. In a firearm having a receiver and a bolt with an operating rod disposed for reciprocation between a forward battery position and a rearward recoil position, a magazine unit for cartridges, said magazine unit including a case having a pair of sides, a partition dividing said case to form a primary magazine between said partition and one of said sides and a reserve magazine between said partition and the opposite one of said sides, each said primary and reserve magazines being adapted to hold a double stack of the cartridges in staggered arrangement, a mouth for receiving the cartridges from said primary and reserve magazines in position for longitudinal extraction by the bolt during travel to the battery position, a pair of lips respectively formed in said pair of sides at said mouth, a divider section of said partition arranged in cooperation with said lips for positioning a leading one of the cartridges from one of said primary and reserve magazines at said mouth for extraction by the bolt, a follower spring-biased in each of said primary and reserve magazines towards said mouth to an over-travel position for pressing the cartridges in said primary and reserve magazine to said mouth, and a switch device mounted in the receiver for cooperation with the operating rod and with said follower in said primary magazine to release for extraction by the bolt the cartridges in said reserve magazine when the cartridges in said primary magazine are depleted.

4. The invention as defined in claim 3 wherein said switch device includes a depressor actuatable between a retaining position and a release position, a retainer tab formed on said depressor so as to contactably hold the cartridges in said reserve magazine away from contact by the bolt when said depressor is in the retaining position and to release said cartridges in said reserve magazine for extraction by the bolt when said depressor is in the release position, and an actuator displaceable by said follower in said primary magazine from a disengaged to an engaging position, a finger on said actuator contactable with a cam surface on the operating rod when said actuator is in the engaging position for actuating said actuator to the release position thereof during travel of the bolt to the recoil position, and means for connecting said actuator and said depressor together so that displacement of said actuator to the release position thereof is transferred 6 to said depressor for actuation thereof to its release position.

5. The invention as defined in claim 4 wherein said switch device includes a pin for mounting said depressor and said actuator for pivotal displacement to their respective reserve position, an elongated orifice in said actuator for mounting said actuator on said pin for translational displacement between the engaging and disengaged positions respective to said depressor, and an arm on said actuator contactable by a shaft on said follower in said primary magazine when the last one of the cartridges therein is extracted by the bolt for transferring displacement of said follower in said primary magazine to the overtravel position, then to said actuator for displacement thereof to the engaging position after the last one of the cartridges in said primary magazine is extracted therefrom.

6. The invention as defined in claim 5 wherein said cam surface and said arm are designed to cooperate so that said arm is free of said shaft when said actuator is displaced to its release position, and including a spring disposed between said actuator and said depressor for biasing said actuator to the disengaged position, and an end on said arm contactable with said shaft when said actuator is in the disengaged position and said follower in said primary magazine is in its overtravel position after the last of said cartridges is extracted therefrom for blocking said actuator in its release position.

References Cited UNITED STATES PATENTS 2,217,848 10/1940 Schillstrom 42-50 FOREIGN PATENTS 90,189 1/1897 Germany.

BENJAMIN A. BORCHELT, Primary Examiner,

Patent Citations
Cited PatentFiling datePublication dateApplicantTitle
US2217848 *Apr 1, 1939Oct 15, 1940Schillstrom Adolf VictorCartridge case for firearms
*DE90189C Title not available
Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US3604142 *Jun 30, 1969Sep 14, 1971Us ArmyFour-stack cartridge magazine
US3672089 *Aug 13, 1969Jun 27, 1972Us ArmyLarge capacity magazine
US4109401 *Aug 22, 1977Aug 29, 1978Daniel Dennis MusgraveMagazine contents indicators
US4127954 *Apr 7, 1977Dec 5, 1978Erich HausmannExtended capacity cartridge magazine structure
US4672760 *Dec 4, 1985Jun 16, 1987Ram-Line, Inc.Side-by-side cartridge magazine for rim-fire cartridges
US4707941 *Jun 16, 1986Nov 24, 1987Eastman Peter MBulk cartridge magazine for firearms and process for loading
US4723369 *Feb 11, 1986Feb 9, 1988Browning Arms CompanyBolt assembly
US4790094 *Dec 3, 1986Dec 13, 1988Pam-Line, Inc.Side-by-side cartridge magazine for rim-fire cartridges
US5099595 *Jun 5, 1990Mar 31, 1992Ram-Line, Inc.Magazine for a firearm
US6070352 *Nov 12, 1998Jun 6, 2000Colt's Manufacturing Company, Inc.Firearm magazine cartridge converter
US8037800 *Oct 22, 2008Oct 18, 2011Armatac Industries IncorporatedDrum magazine for firearm
US8061071Jul 17, 2009Nov 22, 2011Magpul Industries Corp.Ammunition magazine with four ammunition stacks
US8448364Sep 16, 2011May 28, 2013Michael J. DavidsonDouble stack box magazine for rimmed cartridges of varying length
US8572877 *Mar 25, 2011Nov 5, 2013ArmWest, LLCHigh capacity magazine
US8739446 *Mar 25, 2011Jun 3, 2014ArmWest, LLCHigh capacity magazine with multiple springs
US8813406Nov 27, 2013Aug 26, 2014ArmWest, LLCHigh capacity magazine with multiple springs
US8844183 *Nov 4, 2013Sep 30, 2014ArmWest, LLCHigh capacity magazine
US8919021 *Aug 30, 2013Dec 30, 2014O.F. Mossberg & Sons, Inc.Method and apparatus for stripping and feeding cartridges
US8973483Mar 14, 2013Mar 10, 2015Arm West, LlcGas regulator system
US9038525Jan 12, 2012May 26, 2015ArmWest, LLCFirearm
US9228786Jan 13, 2012Jan 5, 2016ArmWest, LLCQuick barrel change firearm
US20100126053 *Jul 17, 2009May 27, 2010Magpul Industries Corp.Ammunition Magazine with Four Ammunition Stacks
US20110005114 *Oct 22, 2008Jan 13, 2011Michael Raymond SnowDrum magazine for firearm
US20120167429 *Mar 25, 2011Jul 5, 2012Armwest, Inc.High capacity magazine
US20140068986 *Aug 30, 2013Mar 13, 2014O.F. Mossberg & Sons, Inc.Method and apparatus for stripping and feeding cartridges
Classifications
U.S. Classification42/18, 42/50
International ClassificationF41A9/00, F41A9/69
Cooperative ClassificationF41A9/69
European ClassificationF41A9/69