US3498178A

US3498178A - Cylindrical ammunition magazine for storing and discharging linked ammunition

Info

Publication number: US3498178A
Application number: US707697A
Authority: US
Inventors: Elwyn A Meyer; Charles L Brownfield
Original assignee: Emerson Electric Co
Current assignee: Emerson Electric Co
Priority date: 1968-02-23
Filing date: 1968-02-23
Publication date: 1970-03-03
Anticipated expiration: 1987-03-03
Also published as: GB1213771A; JPS4841638B1; FR2002434A1; DE1904107A1

Description

March 3, 1970 MEYER ETAL 3,498,178

D DISCHARGING CYLINDRICAL AMMUNITION MAGAZINE FOR STORING AN LINKED AMMUNITION 4 Sheets-Sheet 1 Filed Feb. 25, 1968 I. 7 I I V r I 3W0; ELWVM A. MEYER CHARLES L. BROWIUFIELD March 3, 1970 3,498,178 CHARGING E. A. MEYER ET AL CYLINDRICAL AMMUNITION MAGAZINE FOR STORING AND ms LINKED AMMUNITION 4 Sheets-Sheet 2 Filed Feb. 23, 1968 W l 060 NM i600 0 a m w w .m

FIG/Z 3% ELWVM A. MEYER CHAPLES L. BROWUF'IELD 20 March 3, 1970 E. A. MEYER mm. 3,49

CYLINDRICAL AMMUNITION MAGAZINE FOR STORING AND DISCHARGING LINKED AMMUNITION Filed Feb. 23, 1968 4 Sheets-Sheet 3 FIG. 2) 3mm ELWVM A. MEYEI? CHAEL LES L. BROWNFIELD March 3, 1-970 E. A. MEYER EI'AL 3,498,178

CYLINDRICAL AMMUNITION IAGAZINE FOR STORING AND DISCHARGING v LINKED AMMUNITION Filed Feb. as, 1968 4 Sheets-Sheet 4 ELwvIv A. MEYER United States Patent 3,498,178 CYLINDRICAL AMMUNITION MAGAZINE FOR STORING AND DISCHARGING LINKED AMMUNITION Elwyn A. Meyer, Granite City, 11]., and Charles L. Frownfield, St. Louis, Mo., assignors to Emerson Electric Co., St. Louis, Mo., a corporation of Missouri Filed Feb. 23, 1968, Ser. No. 707,697

Int. Cl. F41c /10 US. CI. 8934 9 Claims ABSTRACT OF THE DISCLOSURE An ammunition magazine for storing and discharging linked ammunition. The magazine includes a fixed support assembly including a fixed helical ramp ascending the height of one layer of ammunition in a smgle turn and a fixed vertical drum interior of the ramp; a rototing vertical drum assembly rotatably supported by the fixed support assembly, including an inner and an outer rotating drum joined at the top, the space between the two rotating drums defining an ammunition storage channel; driving fingers attached to the inner surface of the outer rotating drum to drive ammunit on along the fixed ramp; and helical support fins to gu de and support ammunition above the fixed ramp. A drive mechanism synchronously drives a gun and turns the rotating drum assembly.

BACKGROUND OF THE INVENTION This invention relates to ammunition storage magazines and in particular to a simplified magazine for automatic loading, compact storage, and positive dispensing of linked ammunition.

Cylindrical magazines for linked ammumtlon are 1n general use in gun installations, particularly in helicopters and tanks. These containers have generally consisted of a single outer cylinder with a continuous helical ramp on the inner wall of the cylinder. Linked ammunition is driven in single file along this ramp by a fluted drive shaft within the cylinder. Because the ammunition 15 generally stored in nose fan configuration, the flutes are designed to engage the noses of the cartridges.

One of the objects of this invention is to provide a magazine which is lighter than presently known magazlnes.

Another object is to provide such a magazine which stores ammunition more compactly than presently known magazines.

Another object is to provide such a magazine which lessens the possibility of jamming of ammunition within the magazine, particularly in vehicles such as helicopters which often descend rapidly.

Another object is to provide such a magazine which dispenses cartridges more smoothly and positively, and

with less internal friction than presently known magazines.

Still another object is to provide such a magazine which puts less strain on linkages between cartridges, and hence better guards against gun jams caused by linkage slips, than presently known magazines.

Other objects will appear to those skilled in the art in the light of the following description and accompanying drawings.

SUMMARY OF THE INVENTION In accordance with this invention, generally stated, a cylinder type ammunition storage and dispensing system is provided in which belted ammunition is carried in a ice channel formed between an inner rotating cylinder and an outer rotating cylinder, which are operatively joined to rotate as a single unit. The unit is rotated by a drive mechanism, in one direction for loading and in the opposite direction for dispensing ammunition.

In the preferred embodiment, driving fingers attached to the outer rotating cylinder engage the base of each cartridge to drive the cartridge around a helical ramp making a single turn around the cylinder. The magazine then carries the ammunition in stacked helical configuration throughout the rest of its height. The rotating cylinders are so proportioned that cartridges in each successive reach of cartridges lie between cartridges in the reach above, forming a nested configuration. In unloading, the fingers push each cartridge, as it reaches the lowermost layer, down the ramp and out toward a gun. Support fins, which may be extensions of these fingers and which are also attached to the outer cylinder, n'se helically around the outer cylinder. T-hese fins extend between adjacent cartridges in each layer and act to support and guide the stacked cartridges both in loading and in dispensing the ammunition.

Also in the preferred embodiment, a fixed cylinder inside the rotating unit rotatably supports the rotating unit. The helical ramp, on which the lowermost reach of cartridges lies, is secured to the fixed cylinder.

Because the cartridges rest on the ramp support only along their lowermost reach and rest upon each other (and the support fins) in a nested configuration throughout most of the height of the cylinder, more compact storage is possible than with presently known magazines, and less weight is added by the magazine than presently. Furthermore, because of the configuration of the shells within the system and because both walls of the ammunition channel rotate at the same speed as the ammunition when ammunition is loaded or dispensed, the ammunition moves very little with respect to any surface which it touches, except the surface of the helical ramp at the bottom reach of ammunition. Thus, the area in which friction must be reduced is severely limited. When the system is used in an aircraft, the support fins prevent the ammunition from floating when the aircraft descends rapidly, and thus prevents loss of positive dispensing of ammunition and also possible cocking and jamming of the ammunition in the channel. The short distance each cartridge is driven relative to the storage channel, the positive engagement of the base of each cartridge in the lowermost reach by the driving fingers, the restraint on movement of each of the other cartridges by the support fins and the nested configuration of the stored cartridges all tend to lessen the strain on the links between cartridges.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings, FIGURE 1 is a view in perspective, partly broken away, of one illustrative embodiment of ammunition magazine of this invention;

FIGURE 2 is a bottom plan view of the magazine shown in FIGURE 1;

FIGURE 3 is a sectional view taken along the line 3-3 of FIGURE 2;

FIGURE 4 is a somewhat diagrammatic sectional view taken along the line 44 of FIGURE 3;

FIGURE 5 is a fragmentary sectional view taken along the line 5-5 of FIGURE 4;

FIGURE 6 is a fragmentary sectional view taken along the line 6-6 of FIGURE 2;

FIGURE 7 is a fragmentary sectional view taken along the line 7-7 of FIGURE 5;

FIGURE 8 is a sectional view taken along the line 8-8 of FIGURE 5; and

FIGURE 9 is a detail of a driving finger for use in the illustrative embodiment of ammunition magazine shown in FIGURES 18.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings, reference numeral 1 indicates one illustrative embodiment of ammunition magazine of this invention. The magazine 1 is adapted to store and dispense forty-millimeter cartridges 2 having a hook and eye type linkage 3. The magazine 1 includes a fixed support assembly 10, a rotating drum assembly 200, and a drive mechanism 300.

The fixed support assembly includes a cylindrical support base 11 having a cylindrical wall 12 supported around its inner face by an upstanding vertical arm 14 of a lower angle ring 13 and by a downward flange 16 of an upper ring casting 15. An inward spur 17 of the ring casting acts as a support ring for the drive mechanism 300. An upward flange 18 is provided above the spur 17 on the ring casting .15. A vertical support drum is supported near its lower end by the outer face of the upward flange 18. The'support drum 30 is supported at its upper edge by the outer face of an inverted U-ring by four bolts 42 having nuts 43 and washers 44 in the channel of the U-ring 35. The cover is also secured to the upper face of the inverted U-ring by four metal screws 47. A central lifting bolt 45 is secured to the bracket 41 by a nut 46 through an aperture in the cover 40.

Through an arc of approximately 45 the upward flange 18 of the ring casting 15 widens to form an upward protrusion 20. A slot 21 is provided through the protrusion 20 and the adjacent surface of the support drum 30.

Outboard of the fixed support drum 30, the fixed support assembly 10 includes an ammunition bearing assembly 50 and a rotating drum bearing assembly 110.

The ammunition bearing assembly 50 includes a level horizontal floor 51 supported along its inner edge by the lower face of a spur 22 extending outwardly from the ring casting 15 below the inward spur 17. The floor 51 is supported from below by four

box braces

52a, 52b, 52c and 52d and three

triangular lbraces

53a, 53b and 53c. Each box brace 52a-d includes a pair of angle brackets 54, the upper horizontal arms 55 of which are secured to the lower face of the floor 51. The vertical arms 56 of the angle brackets 54 are secured to the vertical arms of L-brackets 57, the lower, horizontal arms of which are secured to a box brace base 58. The box brace base 58 is secured at its inner edge to the lower face of the horizontal arm of the lower angle ring 13 of the support base 11, and at its outer edge to a lower inwardly turned foot 61 of a forging 60. A pair of upper inwardly extending arms 62 of the forging support the floor 51 at its outer edge and space the Lbrackets 57 from each other. An outwardly extending lug 63 is provided on the forging 60,

for bolting the ammunition magazine 1 into operative position. Apertures 64 may be provided in the L-brackets 57 to reduce weight.

Foot plates 65 are provided on two opposing box braces 52a and 52d near the inner edges of their bases 58, to protect the magazine assembly 1 and to assure that most of its weight is borne by the central support assembly.

Each triangular brace 53ac includes a gusset plate 66 in the form of a right triangle. A hole 68 is provided in the plate 66 to reduce weight. A tail 67 along a vertical edge of the plate 66 is attached to the outer face of the wall 12. The spine of a horizontal T-rail 69 is attached along the upper, horizontal, edge of the plate 66 to one face of the plate 66. The base of the T-rail 69 is attached to the floor 51. The spine of a second T-rail 70 is attached to the other face of the plate 66 along the hypotenuse of the plate 66. The lower end of the spine of the T-rail 70 is secured to a tab 71, a tail of which is attached to the wall 12 in a direction opposite that of the tail 67.

In the floor 51 a trapezoidal cutout is provided between the triangular brace 53a and the box brace 52d. A

chute assembly 76 extends downwardly through the cutout 75 as shown particularly in FIGURE 5. The chute assembly 76 includes a pair of

side pieces

77 and 78 extending downwardly in the planes of the radially outer and inner edges of the cutout 75 and secured to the floor 51 by

flaps

79 and 80 respectively. Mounted between the sidepieces 77 and 78 is a ramp assembly 81 including a lower ramp 82, having integral with it a pair of upwardly raised flat parallel rails 83 throughout its length, and an upper ramp 84 having a complementary pair of downwardly raised integral rails 85. The supper ramp 84 and the lower ramp 82 are spaced from one another and supported by a pair of

vertical ramp walls

86 and 87 which are in turn supported by the sidepieces 77 and 78 of the chute assembly 76. The upper and lower ramps are so spaced that the distance between the rails 83 and is equal to or slightly greater than the diameter of a round of ammunition to be stored. This distance is held constant throughout the length of the ramp assembly 81. The upper ramp acts merely as a guide to keep ammunition passing through the chute from becoming misaligned. The chute assembly 76 rises clockwise from the level of the box brace bases 58 to a point at which the lower ramp 82 is resting on the floor 51 at the lip of the cutout 75, near the triangular brace 53a.

Toward its lower end the chute assembly 76 passes through the box brace 52d. To allow it to pass through, rectangular apertures are provided in the L-brackets 57, and the side walls of the forging 60 are narrowed in the box brace 52d.

Somewhat before the lower ramp 82 reaches the floor 51, the upper ramp 84 terminates in a splitter piece 88. The splitter piece 88 is in the form of a forked wedge or V, a lower arm 89 of which is held securely on the upper face of the upper ramp 84, to form a smooth continuation of the upper ramp 84, as shown in particular in FIG- URE 5.

The lower and upper faces respectively of the lower ramp 82 and the upper ramp 84 are reinforced by transverse brackets 90. At the lower end of the chute assembly 76, the ramp assembly 81 is provided with detents for mounting a standard flexible ammunition chute, not here shown.

Starting at the upper end of the lower ramp 82 and extending clockwise around the upper face of the floor 51 at a uniform incline to an upper arm 91 of the splitter 88, nearly the diameter of a cartridge higher than the upper end of the lower ramp 82, is a helical ramp 95. The helical ramp 95 is proportioned to form a continuous surface with the lower ramp 82 of the chute assembly 76. The helical ramp 95 is supported through its lower reach by

blocks

96, 97, 98, 99 and 100. Through its remaining reach, the helical ramp 95 is supported on its outer and lnner margins by angle supports 101 and 102 respectively. The upper end of the helical ramp 95 is secured to the upper surface of the upper arm 91 of the splitter piece 88, which is proportioned to form a continuous Surface with the upper end of the ramp 95.

The rotating drum bearing assembly includes three bearing race assemblies adapted to cooperate with hearing race assemblies carried by the rotating drum assembly 200.

A lower inner race assembly 111 is secured to the upper face of the spur 22 on the ring casting 15 by studs 112 through the floor 51 and spur 22. The studs 112 also give support to the floor 51. A raceway 113 in the outer face of the race assembly 111 is adapted to carry

balls

114 and 115. The halls 115 are smaller than the balls 114 and are arranged alternately with the balls 114.

An upper inner race assembly 116 is secured to the outer arm of the inverted U-ring 35 at the top of the fixed drum 30. A raceway 117 on the outer face of the race assembly 116 is adapted to carry

balls

118 and 119 identical with the

balls

114 and 115 carried by the lower bearing 111.

An outer race assembly 120 is provided along the outer edge of the floor 51. The race assembly 120 is supported by the forgings 60 at the outer ends of the box braces 52, and by the outer ends of the triangular braces 53. The outer race assembly 120 includes a cast ring comprising a horizontal ring 121 and an upstanding vertical ring 122 in which is cut a rabbeted raceway 123 adapted to carry balls 124. p

The rotating drum assembly 200 includes an inner drum 201 and an outer drum 202 radially separated from each other to form a cartridge carrying channel 203 of a width equal to, or slightly greater than, the length of a cartridge to be stored. The inner drum 201 is mounted rotatably on the support assembly by

race assemblies

111 and 116 on the fixed support assembly 10. The

race assemblies

111 and 211 .and

balls

114 and 115 and the

race assemblies

116 and 216 and the

balls

118 and 119 thus form a lower and an upper lateral and thrust bearing for the rotating drum assembly 200. The upper race assembly 216 on the inner rotating drum 201 has an outwardly extending flange 218 having a downwardly extending rim 219 on the inner face of which is secured the outer drum 202.

A race assembly 220, attached to the lower outside edge of the outer drum 202, is adapted to cooperate with the outer race assembly 120 on the outer edge of the floor 51. The race assembly 220, the race assembly 120 and the balls 124 thus also form a bearing for the rotating drum assembly 200.

Mounted on the upper face of the race assembly 221 is an internally toothed gear ring 230 for transmitting rotational drive power to the rotating drum assembly 200.

At the inner surface of the lower margin of the outer rotating drum 202, in this illustrative embodiment, are attached thirty-six equally spaced driving fingers 240. Each of the fingers 240 is of a modified teardrop shape, having a lower vertical face and an upper flat sloping face on the side of the finger 240 which is forward when the drum assembly 200 is driven in a clockwise direction. The fingers 240 are radially narrower than the spacing between the outer drum 202 and the helical support ramp 95, and revolve outboard of the support ramp 95.

Attached to the driving fingers 240 are helical support fins 241, which are wider than the driving fingers 240 and thus extend farther into the cartridge carrying channel 203 defined by the outer drum 202 and the inner drum 201. However, the support fins 241 must not extend a distance gerater than that between the base of a cartridge 2 and its linkage 3, because each fin is adapted to lie between two adjacent cartridges in each reach of cartridges stored. Each helical support fin 241 rises in a counterclockwise helix from a driving finger 240 to near the flange 218 at the top of the cartridge carrying channel 203. The pitch or lead angle of the support fins 241 is dependent on the precise radius of the outer rotating drum 202 and is limited to a minimum pitch by the length of the linkage 3 between adjacent rounds of the belted ammunition. The radius of the outer cylinder 202 is preferably such that each cartridge will lie circumferentially between the cartridges axially above and below it and will lie as axially compactly as possible between them. Each support fin 241 is provided with a spine 242 by which it is attached to the inner surface of the outer rotating drum 202.

The helical support fins 241 thus form thirty-six cartridge support channels 243. Each cartridge remains in the support channel 243 into which it is originally drawn by the driving fingers 240. The support chann ls 243 define generally the natural movement of cartridges in the cartridge carrying channel 203 between the outer rotating drum 202 and the inner rotating drum 201. However, the helical support fins 241 do partially support the cartridges, help in driving the cartridges when the magazine 1 is being loaded or is discharging cartridges, guide the car-\ tridges and prevent them from cocking during these operations, and restrain floating of the cartridges when the vehicle in which the magazine 1 is mounted descends rapidly.

The drive mechanism 300 is supported by the inward spur 17 on the ring casting 15, by a drive support bar 301 mounted across the inward spur 17 and bolted to it, and by a control system mounting bar 302 supported by a control system mounting ring 303 attached to the inner face of the fixed support drum 30 above the ring casting 15. The drive mechanism 300 includes a control system 304 suspended from the control system support bar 302. The control system 304 is a standard electrical motor control device for controlling the direction of rotation of a drive motor 306 The drive motor 306 drives a standard step-down gearing system 307 which drives a main drive gear 309 The main drive gear 309 extends through the slot 21 in the upward protrusion 20 of the ring casting 15 and meshes with the internally toothed gear 230 on the rotating drum assembly 200 The gearing system 307 also drives a splined extension 308 adapted to carry a flexible drive shaft for driving an externally powered gun or weapon, not shown, in synchronization with the magazine, when the magazine is dispensing ammunition.

In operation, the magazine 1 is lifted into place by the central lifting bolt 45 and bolted into place at the lugs 63 on the box braces 52. Belted ammunition is fed into the chute assembly 76 and the drive motor 306 is activated to turn the rotating drum assembly 200 in a clockwise direction. Each driving finger 240 engages the base of a cartridge 2. When the first cartridge in the magazine has traveled to the end of the splitter piece 88, it drops into place between two incoming cartridges. The rotating drum assembly 200 is rotated clockwise until the channel is filled with cartridges to its top. A rounds counter 350 reactivates the drive motor 306 when the magazine 1 is filled to capacity. When the gun fed by the magazine 1 is fired, the drive motor 306 is activated to turn the rotating drum assembly 200 in a counterclockwise direction. The drive fingers 240 then draw the lowermost layer of ammunition around the helical support ramp and out through the chute assembly 76 to the gun. As the lower reach of ammunition is forced out through the chute assembly 76 each cartridge in each successive upper reach drops downward axially and slightly rearward (clockwise) under the influence of gravity and the support fins 241 on either side of it.

It will be seen that although the helical support fins 241 perform some driving and guiding function, the primary driving force is applied by the drive fingers 240 on the lower reach of ammunition, and the upper reaches of cartridges are pushed primarily by the lower reaches because of the nested configuration in which successive reaches are stored. It will also be seen that although the ammunition travels approximately the same distance relative to the fixed support assembly as does ammunition in a more conventional cylindrical ammunition magazine it moves only a short distance (axially and, in a direction opposite the direction of rotation of the rotating drum assembly, circumferentially) relative to the walls of the channel in which it is carried. Therefore, the problem of reducing friction is practically limited to friction between the lower reach of ammunition and the helical support ramp 95. Coatings of known release agents such as polytetrafluoroethylene in a resinous binder may be applied to the helical ramp 95, to reduce friction along the ramp. It will also be seen that the nested configuration of the cartridges and the weight of the upper reaches of ammunition on the lower reach tend to give more positive alignment of the cartridges and thereby reduce floating and cocking. It will also be seen that less strain is put on the linkages between cartridges.

Numerous variations in construction of the ammunition magazine of this invention will become apparent to those skilled in the art in the light of the foregoing disclosure.

For example, the support assembly could be outboard of the rotating assembly, although this construction is more bulky than that of the illustrative embodiment shown. A gap may be provided in the lower ramp of the chute assembly for loading the magazine without disturbing a flexible chute assembly attached to the magazine chute assembly. The helical support ramp may be dispensed with, although in this case nesting of the cartridges is much more difiicult, and more strain is put on the chute assembly and cartridge linkages. The helical support fins on the rotating drum assembly may be.made integral with the driving fingers, may be placed on the inner rotating drum rather than, or in addition to, on the outer drum, or may be dispensed with entirely. Support fins having means for engaging rims on the bases of car tridges may be provided, and the inner rotating drum omitted. The rotating drum assembly may be made easily removable from the fixed support assembly for preloading and hence for more efiicient loading of the magazine. The drive assembly may be electronically rather than mechanically connected to the gun motor and may be located outside of the rotating drum assembly. These variations are merely illustrative.

Having thus described the invention, what is claimed and desired to be secured by Letters Patent is:

1. An ammunition magazine adapted to carry a continuous belt of ammunition in a number of successive reaches, comprising a helical ramp, said ramp being adapted to support cartridges, said ramp making at least one turn but fewer turns than the number of successive reaches of ammunition said magazine is adapted to carry, the lower end of said ramp being open for discharging said belt of ammunition.

2. The ammunition magazine of claim 1 including means for restricting radial movement of ammunition carried by said magazine, said means comprising a vertical cylinder, a substantial portion of said cylinder being disposed axially above said helical ramp.

3. The ammunition magazine of claim 2 wherein said ramp is fixed to a base, said cylinder is rotatably mounted on said base, and cartridge driving means are provided on said cylinder, said cartridge driving means being adapted to engage cartridges supported by said ramp.

4. An ammunition magazine adapted to carry a continuous belt of ammunition in a number of successive reaches, comprising a helical ramp fixed to a. base, said ramp being adapted to a support cartridges, said ramp making at least one turn but fewer turns than the number of successive reaches of ammunition said magazine is adapted to carry, a cylinder adapted to restrict radial movement of ammnunition carried by said magazine, a substantial portion of said cylinder being disposed axially above said helical ramp, said cylinder being rotatably mounted on said base, and cartridge driving means on said cylinder, said cartridge driving means being adapted to engage cartridges supported by said ramp.

5. An ammunition magazine adapted to carry a continuous belt of ammunition in a number of successive reaches, comprising a helical ramp, said ramp being adapted to support cartridges, said ramp making fewer turns than the number of successive reaches of ammunition said magazine is adapted to carry, the lower end of said ramp being open for discharging said belt of ammunition.

6. The ammunition magazine of claim 5 including means for restricting radial movement of ammunition carried by said magazine, said means comprising a vertical cylinder, a substantial portion of said cylinder being disposed axially above said helical ramp; a base, said ramp being fixed to said base, said cylinder being rotatably mounted on said base, and cartridge driving means on said cylinder, said cartridge driving means being adapted to engage cartridges supported by said ramp.

7. The ammunition magazine of claim 6 wherein said cylinder is so proportioned that successive reaches of cartridges lie in nested configuration, and including elongate helical support fins mounted on said cylinder, said support fins forming extensions of said cartridge driving means, the lead angle of said fins being substantially greater than the lead angle of said ramp.

8. The ammunition magazine of claim 5 wherein said ramp makes about one turn.

9. An ammunition magazine comprising a fixed support assembly; means for carrying a continuous belt of cartridges in a number of successive reaches in a stacked configuration, said means comprising a rotating assembly rotatably supported by said support assembly, said rotating assembly comprising a first rotating cylinder and a second rotating cylinder radially within said first cylinder, said first rotating cylinder and said second rotating cylinder defining the outer and inner walls of a cartridge carrying channel and being so proportioned that successive reaches of said belt of cartridges lie in nested configuration; cylinder driving means adapted to rotate said rotating assembly; cartridge driving means mounted on said rotating assembly and extending within said channel, said cartridge driving means being adapted to engage cartridges within said cartridge carrying channel, and elongate helical support fins mounted on said rotating assembly, said support fins forming extensions of said cartridge driving means, the lead angle of said fins being substantially greater than the lead angle of said reaches of said belt of cartridges.

References Cited UNITED STATES PATENTS 5/1958 Houston et a1 89-33 5/1967 Casull 8933