Ammunition cartridge

A bullet is fired from an ammunition cartridge upon piercing a breakaway section in the rear wall of the cartridge to form a gas escape port. The cartridge has one open end in which is seated the bullet and the breakaway section of the rear wall is directly opposite the bullet. A moveable sealing element is adapted to move between two positions. One position seals off the opening in the one end, and the other position is displaced from the opening to allow gas to escape under pressure from the opening. Piston-type element, in response to the housing wall being pierced, stops the flow of gas from this escape port and moves the sealing element from the first to the second position.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates to ammunition and particularly ammunition cartridges 
that contain pressurized gas as the means for propelling a bullet held by 
the cartridge. 
2. Background Discussion 
It has long been a common practice to use gunpowder which, when ignited, 
generates gases that propel a bullet. The gunpowder is retained in a 
cartridge and the bullet is fitted tightly in the open end of the 
cartridge. When the firing pin strikes the ignition point on the 
cartridge, the gunpowder explodes, generating gases which propel the 
bullet from the cartridge. 
Some guns instead of using gunpowder propel the bullet by means of 
pressurized gas, in most instances air. These guns usually contain a 
chamber which is filled with pressurized air, and then when the gun is 
fired, the air is released rapidly from the chamber to force the bullet 
from the barrel of the gun. Generally these guns have had only limited 
acceptance because of various factors, one of which is that the bullet 
fired from such a gun does not have an acceptable range or accuracy. Air 
guns that do approach the accuracy and range of the more conventional guns 
employing cartridges containing gunpowder are very expensive. 
BRIEF DESCRIPTION OF THE INVENTION 
I have now invented ammunition which propels a bullet from a cartridge 
holding it by means of pressurized gas contained within the cartridge. The 
bullet is seated adjacent a cylinder containing pressurized gas and it is 
propelled from the cartridge upon the release of the gas. The cartridge 
contains sealing means which normally are closed to prevent the release of 
gas from the cylinder. These means open in response to the cartridge being 
pierced to provide a gas escape port. 
The sealing means include a piston which moves axially when the cartridge 
is pierced. The piston divides the cylinder into two chambers which each 
contain gas under pressure. The gas pressure is equal initially, but 
piercing of the cartridge creates a pressure differential which causes the 
piston to move the sealing means to the open position, causing the bullet 
to be propelled from the cartridge. The cartridge has at one end an 
opening and a wall remote from this one end which may be pierced to 
provide the gas escape port for escaping pressurized gas from the one 
chamber of the cylinder. Gas escapes almost instantly from the other 
chamber upon the sealing means moving to the open position. The movable 
sealing means serve as the means for controlling release of the 
pressurized gas for propelling the bullet from the cartridge. 
The movable sealing means are adapted to move between a first position 
where it seals off the opening in the one end of the housing and a second 
position displaced from the opening to allow gas to escape under pressure 
from the opening. There are means in the housing which, in response to the 
housing wall being pierced to form the gas escape port, stop the flow of 
gas from the escape port and move the sealing means from the first 
position to the second position. Thus substantially all the pressurized 
gas in the housing exits through the opening in the housing rather than 
the gas escape port. This gas, being at a very high pressure, impinges 
against the end of the bullet retained in the cartridge and forces the 
bullet from the cartridge at a very high velocity. In other words, when 
the sealing means moves to the second position, the bullet sees gas at 
very high pressure just as if there was an explosion of gunpowder within 
the cartridge. The gas pressure in the cylinder normally exceeds 500 
pounds per square inch and typically ranges between about 500 and about 
1200 pounds per square inch (psi). The heavier the bullet the more 
pressure required, however. Too much pressure results in loss of control 
of the direction of flight of the bullet. Too little results in loss of 
range. 
The ammunition of this invention has several advantages. First, because 
there is no explosion, there is essentially no recoil of the gun using 
this ammunition. Second, since an explosion does not occur, there is no 
fire or heat generated when the ammunition is discharged. Consequently, 
there is no nozzle flame. The lack of a nozzle flame is very desirable for 
military applications since the location of firing of the gun cannot be 
traced by observation of the nozzle flame. Moreover, because there is no 
explosion, heat is not generated and cooling of the gun is not required. 
The lack of heat and essentially no recoil enables one to make a lighter 
gun. Third, combustion products are not collected in the barrel of the 
gun. Therefore cleaning of the gun is either not required or required only 
infrequently. Fourth, the cartridge of this invention also provides the 
same power and range as a conventional gun such as a M1 rifle. It has an 
advantage over conventional guns such as the M1rifle because the range of 
conventional guns decreases as the gun is heated. Because heating of the 
gun is avoided using the cartridge of this invention, range is not 
diminished. Fifth, the cartridge of this invention may also be reused. 
Therefore it provides a significant cost savings. Sixth, guns using the 
ammunition of this invention do not require gas recycle for rejecting the 
cartridge from the firing chamber.

DETAILED DESCRIPTION OF THE DRAWINGS 
As shown in FIG. 1, the ammunition 10 of this invention includes a 
cartridge 12 having a bullet retaining section 14 which holds a bullet 16 
and a gas retaining section 18 which contains pressurized gas. The bullet 
retaining section 14 and gas retaining section 18 have a common exterior 
wall 20. This wall 20 tapers inwardly to form a restricted annular opening 
22 into which the bullet 16 is force fitted. 
As best shown in FIG. 2, the gas containing section 18 includes a hollow 
cylinder 18a having at one end an interior wall 24 with a central annular 
opening 26 therein. At the opposed end of the cylinder 18a is an external 
rear wall 28 with a central breakaway section 30 which may be pierced to 
provide a gas escape port 32 (FIG. 7) for the pressurized gas contained 
within the cylinder. As shown by FIG. 7, the rear wall 28 is pierced by 
the firing pin 34 of the gun using the ammunition to form the gas escape 
port 32. The cylinder 18a is in two parts, 18b and 18c, with the rear part 
18b containing the breakaway section 30 screwed onto the forward part. The 
parts 18b and 18c are threaded so they may be screwed together. 
Contained within the cylinder 18a is a piston 36. The piston head 42 
divides the cylinder 18a into two chambers, 38 and 40. The piston 36 is 
adapted to move along the longitudinal axis a of the cylinder 28a between 
two different positions, a closed position and an open position. In the 
closed position (shown in solid lines in FIG. 2) the tapered end 44a of 
the stem 44 of the piston fits snug into the annular opening 26 in the 
internal wall 24 of the cylinder 18a. In the open position (shown in 
dotted lines in FIG. 2) the end 44a of the stem 44 is displaced inwardly 
so that pressurized gas contained within the chamber 38 will flow through 
the opening 26 and force the bullet from the bullet retaining section. The 
position of the stem end 42a with the piston in the open position is best 
shown in FIG. 5. 
The piston head 44 fits snug against the inner wall of the cylinder 18a and 
the stem 44 is coaxial with the longitudinal axis a of the cylinder. The 
stem 44, being hollow, provides a passageway 46 which has a gas entry port 
48 at one end and an opening 50 in its other end. A plug member 52 fits 
snug within the opening 50 and prevents gas from escaping through this 
opening. The stem 44 has a first chamber fill port 54 along its side. 
Gases flowing along the passageway 46 flow through this fill port 54 into 
the chamber 38. 
There is a one-way valve 56 disposed in the passageway 46 adjacent the 
annular opening 26 in the wall 24, and it is disposed between this opening 
26 and the fill port 54. The valve 56 includes a needle 58 whose tip is 
inserted into the gas entry port 48 in the stem 44. As shown in FIG. 3, an 
intermediate portion of the needle 58 has an enlarged member 60 of 
triangular cross-section, and a coiled spring 63 seated between the 
enlarged member 60 and the end of the plug member 52 urges the pointed tip 
of the valve 56 into the gas entry port 48. This valve configuration 
allows gas to flow past the needle and by the enlarged member 60 when the 
valve is opened by depressing needle 58. The air is forced under pressure 
through the gas entry port 48 into the passageway 46 to fill the chambers 
38 and 40. How these chambers are filled will be explained in greater 
detail below. 
The plug member 52 is stationary and it has a fill port 62 in its side. In 
the end of the plug member 52 inserted into the passageway 46 is a second 
gas entry port 64. There is a channel 66 (FIGS. 2 and 4) extending between 
this gas entry port 64 and the fill port 62, placing the two chambers 38 
and 40 in communication with each other. The second fill port 62 is 
adjacent the piston head 42 when the piston 36 is in the closed position, 
and when the piston element is in the open position, it moves to cover 
this fill port 62 as shown in FIG. 6. The plug member 52 has at its remote 
end a cylindrical stand 68 which fits over an annular positioning ridge 70 
extending inwardly from the back side of the rear wall 28. In the side 
wall of this stand 68 are a number of windows 72 displaced in equal 
intervals around the circumference of the stand. These windows 72 allow 
gas to flow through the stand 68 when the gas escape port 32 is formed in 
the rear wall 28. 
To assemble, with the rear end unscrewed, the piston 36 containing the 
one-way valve 56 in its hollow stem 44 is inserted into the inside of the 
cylinder 18a so that the tapered end 44a of the stem fits within the gas 
entry port 48. The plug member 52 is then inserted into the open end 50 of 
the stem and into the passageway 46 until the inserted end of the plug 
member is just flush with the fill port 54, but does not block it. The 
coil spring 63 of the one-way valve 56 is biased so that it is forcing the 
pointed tip of the needle 58 into the gas entry port. The rear end of the 
cylinder is then screwed into position as shown in FIG. 1 holding the 
internal components in position. 
Next the chambers 38 and 40 are charged with gas, preferably air. This is 
accomplished by connecting a conventional air pump (not shown) to the gas 
entry port 48 and inserting its tip into the stem 44 to push the needle 58 
inwardly to permit the pressurized air to flow through the passageway 46 
and out the one fill port 54 to fill the chamber 38 and through the second 
gas entry port 64, through the channel 66, and out the second fill port 62 
to fill the other chamber 40. The air is forced into these two chambers 38 
and 40 until the internal air pressure within these chambers exceeds about 
500 psi. The cartridge is now charged with pressurized gas. 
Lastly, the bullet 16 is forced into the bullet receiving section 14, as 
shown in FIG. 1. 
Operation 
To fire the ammunition 10, it is first placed in a conventional firing 
chamber of a rifle such as the U.S. Army's M1 rifle. When the trigger of 
the rifle is pulled, the firing pin 34 pierces the central portion of the 
breakway section 30 to form the gas escape port 32. The pressurized gas in 
chamber 40 flows through the windows 72 in the stand 68 and out the escape 
port 32. Essentially instantaneously, this creates a differential in 
pressure between chamber 38 and chamber 40. This differential in pressure 
causes the piston 36 to move axially to the right as shown in FIG. 1 to 
the open position shown in FIG. 5. In this open position, the piston head 
covers the fill port 62 as shown in FIG. 6. Thus the gas from the chamber 
38 cannot flow into chamber 40. With the piston 30 displaced, the opening 
26 is now uncovered by the removal of the tapered end 44a of the stem. 
This allows the gas in chamber 38 to explode from this chamber out the 
opening. Because of the high pressure of this gas, the bullet is forced at 
high velocity from the bullet retaining section 14 and out the barrel of 
the rifle. 
When all of the gas from chamber 38 has escaped, the pressure in the two 
chambers 38 and 40 will again be equal. The cartridge 12 may now be reused 
by returning the piston 36 to the closed position with the stem end 44a in 
the opening 26 and refilling it with pressurized gas as described above. 
When the chambers 38 and 40 are again refilled, a bullet is again force 
fitted into the open end of the bullet retaining section 14. The cartridge 
is now reloaded and ready for firing. 
The above description presents the best mode contemplated of carrying out 
the present invention. This invention is, however, susceptible to 
modifications and alternate constructions from the embodiment shown in the 
drawings and described above. Consequently, it is not the intention to 
limit this invention to the particular embodiments disclosed. On the 
contrary, the intention is to cover all modifications and alternate 
constructions formed within the spirit and scope of the invention as 
expressed in the appended claims.