Abstract:
A gun preferably designed to rapidly fire paint balls includes a single valve assembly that is inserted into and removed from the gun body. The valve assembly includes a low pressure ram passing through a longitudinal center or core of the assembly, and is capable of being driven in opposite reciprocal directions. A volumizer stores a charge of high pressure gas sufficient to adequately propel a paint ball, and a high pressure poppet valve is driven by movement of the low pressure ram for releasing the charge rapidly. A bolt carried upon the low pressure ram moves a paint ball into firing position just prior to the high pressure discharge. All of the aforementioned components of the cartridge are carried upon a single axis defined by the ram. Means are provided to both align and couple the various components together to ensure proper operation at high firing rates.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
   This application claims priority to U.S. provisional patent application Ser. No. 60/729,814 filed Oct. 22, 2005 entitled “Pneumatic Sleeve, Hammer and Valve Assembly for Paintball Guns and the Like, and Improved Guns Incorporating the Assembly” naming the present inventor, and to U.S. provisional patent application Ser. No. 60/762,969 filed Jan. 26, 2006 also entitled “Pneumatic Sleeve, Hammer and Valve Assembly for Paintball Guns and the Like, and Improved Guns Incorporating the Assembly” and naming the present inventor, the contents of each which are incorporated herein by reference in entirety. 

   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   This invention pertains generally to the field of mechanical guns and projectors, and more particularly to fluid pressure propulsion, with control for discharge of fluid pressure provided by a valve. In a preferred embodiment, the present invention is manifested in a single-axis bolt and valve assembly used within a paintball marker. 
   2. Description of the Related Art 
   Fluid pressure propulsion has been used in combination with various types of guns and projectors for many years. As an alternative to gun powder and other explosive substances, various pump guns existed which allowed an operator to pump air into a chamber until sufficient fluid was compressed to attain the necessary pressure to reasonably fire a projectile Many BB and pellet guns were sold for many years that utilized this technology. These guns, while fully functional and capable of firing projectiles at great speeds, suffered from many significant drawbacks. Foremost among these was the inability to keep the gun in a ready-to-fire state, commonly due to slow leakage through the pumping mechanisms, and the delay time between firing successive shots, necessitated by the need to pump another charge of air into the pressure chamber after each shot. In addition, having been designed to resemble the gun powder versions, they were often rather large and heavy. While weight reduces recoil in gun powder versions, it is of lesser importance in the less powerful pump guns. 
   As an alternative to and improvement over the pump-pressure guns, various gas and liquified gas cylinders were provided to deliver a steady source of fluid pressure to the gun. Exemplary of these were the CO 2  cartridges which were small and lightweight, but which provided a very limited number of successive firings before requiring replacement. To fire these guns, various mechanical triggering devices were used to control the actuation of a valve. Common valves required a substantial amount of time to activate and reset, which in view of the relatively small number of shots available was not normally considered a limitation for these guns. 
   A number of years ago, a new gun was developed which would fire small capsules or balls of paint that were frangible, and so would break relatively easily upon impact. By filling the frangible exterior shell with liquid paint, it was possible to visually determine whether a participant had been “hit”. Consequently, the guns are commonly referred to as markers, since rather than inflicting harm or death, a paintball gun marks the point of impact. The early markers made it possible to conduct relatively close-range training drills for military and civilian training, without the need for other types of complex, expensive and unreliable training weapons or the fear of serious harm that would be associated with more traditional guns 
   Many developments have occurred over the years that have evolved the early paintball guns into the more modern counterparts. These developments have occurred in all aspects, affecting not only the technology of firing and propulsion, but also in areas separate and distinct from the guns, such as safety and in the formal organization of terms and competitions. In a comparatively few recent years, the development has progressed and evolved into both a science and industry of its own. As a sport, paintball has been identified as the third largest participant sport in the United States with millions of participants, has substantial numbers of participants and competitions the world over, and continues to grow in popularity both in numbers of participants and in spectators. 
   One area of development which has and continues to be very challenging to gun designers is the firing rate of a gun. To be most effective, a modern paintball gun will preferably be capable of firing paint balls at rates not measured in balls per second, but instead in the tens of balls per second. More rapid firing rates permit the balls to be distributed through lesser angles of an arc, in the event the gun is being moved while being fired. Since movement and motion are inseparable from paintball, the higher firing rate translates into a greater likelihood of marking an opponent. This can be readily contrasted with the pneumatic guns outside of the paintball industry, where firing rates are more commonly measured in seconds per shot or in only a few shots per second. 
   Another demanding area of development is the size and weight of the gun. While size and weight are often interrelated in most products since a larger product of otherwise identical construction will weigh more, in the case of a paintball gun the size and weight bring about different benefits and so are somewhat independent. With regard to weight, the gun must be held and moved about. At times, such as when surprised by an opponent, the gun will most desirably redirected in as little time as possible. Lower weight guns can he moved about more quickly, and may further be aimed in less time. With regard to size, the gun will sometimes be held out beyond the shelter of a barrier, exposing only the gun and not the person. The smaller a gun, the more difficult it will be to be marked by an opponent. 
   Additional areas that have required much consideration and development have included the reliability of successfully firing the gun, and the ease of cleaning out the gun when a paint ball is broken within the gun. When a paint ball breaks within the gun, a way must be provided to remove the components since paint will be smeared or splashed about inside the gun, and without cleaning, will increasingly interfere with proper operation The more readily the components along the path of the ball are removed, the easier and quicker it will be for a participant to recover from a broken ball. Nevertheless, the precision of components and operation must still be maintained, or there will be many more balls breaking. 
   SUMMARY OF THE INVENTION 
   Exemplary embodiments of the present invention solve inadequacies of the prior art by providing a single cartridge that is inserted into and removed from a gun body. The cartridge includes a low pressure ram capable of being driven in opposite reciprocal directions, a volumizer for storing a charge of high pressure gas sufficient to adequately propel a paint ball, a high pressure valve driven by movement of the low pressure ram for releasing the charge rapidly, and a bolt carried upon the low pressure ram for moving a paint ball into firing position just prior to the high pressure discharge. All of the aforementioned components of the cartridge are carried upon a single axis, through which the low pressure ram passes. Means are provided to both align and couple the various components together to ensure proper operation at high firing rates. 
   As described in a first manifestation, the invention is a valve assembly for paintball guns and the like. The valve assembly has an end cap, a low-pressure ram chamber having at least two ports spaced distally from each other and each operative to allow gas to pass through, and a ram having a ram head and O-ring dividing the low-pressure ram chamber into a first and a second low-pressure enclosure. The first low-pressure enclosure is in communication with a first one of the at least two ports and the second low-pressure enclosure is in communication with a second one of the at least two ports, the first port isolated from the second port. A bolt is coupled for relative movement with the ram and has at least one hole penetrating longitudinally through the bolt, and a plurality of seals cooperative with a gun barrel and feed neck to seal the feed neck from a blast of high pressure gas during gun firing. A volumizer has a high pressure inlet to a volumizer enclosure, and at least one flow port coupling an exterior of the volumizer to the at least one hole penetrating through the bolt. A high pressure valve controls flow from the volumizer enclosure to flow port. Each of the end cap, low-pressure ram chamber, ram, bolt, volumizer and valve are constrained within the valve assembly such that the valve assembly remains a single integrated unit not only during normal operation but also during removal from and insertion into a gun body. 
   In a second manifestation, the invention is a paintball gun. The gun has a feed neck for receiving paint balls into a breech from an external source. A barrel coupler couples the gun to a gun barrel. A source of high pressure gas is coupled to the gun for distribution within the gun. A human interface is provided for manual initiation gun firing. A gun body has a bore therein in line with the barrel coupler. A valve assembly is held within the bore in the gun body, and has an end cap, ram, low-pressure ram chamber, volumizer, valve, and bolt, the ram extending from adjacent the end cap to the bolt and coupled with the valve to activate the valve when the ram is driven away from the end cap. 
   In a third manifestation, the invention is a method of firing a projectile from a hand-held gun having a gun barrel. According to the method, low pressure gas is delivered into an enclosed chamber of variable volume. A ram defining the variable volume is driven responsive to the low pressure gas delivery. A paint ball is advanced from a breech into a firing position within the hand-held gun body responsive to the driving step. A high pressure valve is activated responsive to the driving step and subsequent to the advancing step. High-pressure gas which has been stored within an enclosure is released in a rapid burst responsive to the activating step, and is then conducted to the paint ball and down the gun barrel. 
   OBJECTS OF THE INVENTION 
   A first object of the invention is to provide a paintball gun which will preferably be capable of firing paint balls at rates measured in the tens of balls per second. A second object of the invention is to lower the size and weight of the gun relative to the prior art. Another object of the present invention is to improve the reliability of successfully firing the gun, and also simultaneously ease gun cleaning when a paint ball is broken within the gun. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The foregoing and other objects, advantages, and novel features of the present invention can be understood and appreciated by reference to the following detailed description of the invention, taken in conjunction with the accompanying drawings, in which: 
       FIG. 1  illustrates a paintball gun incorporating the present invention from side plan view with the barrel, magazine and gas cartridge removed. 
       FIG. 2  illustrates a preferred embodiment valve assembly designed in accord with the teachings of the present invention and operative with the preferred embodiment gun Of  FIG. 1 , from a side plan view and in a stationary but ready-to-be-fired position. 
       FIG. 3  illustrates the preferred embodiment valve assembly of  FIG. 2  from a projected plan view and in a during-firing position. 
       FIG. 4  illustrates the preferred embodiment valve assembly of  FIG. 2  from a sectional view taken along section line  4 ′ of  FIG. 3 , which corresponds to a plane parallel to the page in  FIG. 2 . 
       FIG. 5  illustrates the preferred embodiment valve assembly of  FIG. 4  in a position immediately prior to high pressure discharge. 
       FIG. 6  illustrates the preferred embodiment valve assembly of  FIG. 4  in a position during firing, at the time of high pressure discharge, and illustrating the flow of high pressure gas through the assembly. 
   

   DESCRIPTION OF THE PREFERRED EMBODIMENT 
   A paintball gun  100 , also referred to as a paintball marker, is shown by an external side plan view in  FIG. 1 . As illustrated therein, a feed neck  110  is provided for introducing paint balls into gun  100 . The source of paint balls is not consequential to the present invention, but may be a magazine such as a hopper, a powered ball feeder, or other device known in the art to provide a high speed, high volume source of paint balls. The paint balls will pass from feed neck  110  into gun body  120 , where they will rest in the breech From there, the balls will be moved forward, and then fired, or violently expelled by a high-pressure blast, through barrel coupler  124  and out a gun barrel as is known in the art. A high pressure gas canister is coupled, either directly or indirectly, through coupler  130 . High pressure gas will pass from coupler  130  through hose  135  and into pressure regulator  140  for distribution into gun body  120 . A handle  150  and trigger  160  provide the human interface with gun  100  for holding the gun and initiating firing, and handle  150  will often house a battery and electronic controls that may be used with modern paintball guns. 
   Adjacent the end  122  of gun body  120 , distal to barrel coupler  124 , is the very end of valve assembly  200 . Valve assembly  200  is held within a bore in gun body  120  in line with a gun barrel longitudinal axis. This valve assembly  200  is designed to slide into and out from the bore as a single unit, which permits rapid removal for cleaning and repairs. Furthermore, since the bore within gun body  120  is along a single axis and in line with the barrel, both inspection and cleaning are simplified. 
   The preferred embodiment valve assembly  200  is illustrated in  FIG. 2  removed from gun body  120 , but oriented as it would be in  FIG. 1 . Consequently, in  FIG. 1  the only component of valve assembly  200  which is visible is a portion of end cap  210 , including locking and alignment wing  212 . Valve assembly  200  has several primary components in addition to end cap  210 . These include the low-pressure ram chamber  220 , volumizer  240 , and bolt  290 . Each of these components is constrained within valve assembly  200 , such that valve assembly  200  remains a single integrated unit not only during normal operation but also during removal from and insertion into gun body  120 . 
   In operation, at the start of a firing sequence low pressure gas is delivered into port  225 , and simultaneously exhausted from port  229 . The gas will preferably be introduced through small ports or openings within gun body  120  or other suitable tube concentric about valve assembly  200 . The ports that deliver the pressurized gas do not have to align with ports  225  and  229 , but instead must fall between the adjacent O-ring seals. O-rings  224  and  226  will then trap and constrain the flow of pressurized gas with respect to port  225  and O-rings  228 ,  230  trap and constrain the flow of pressurized gas with respect to port  229 , such that the gas can only flow into or from ports  225  and  229  and not be dispersed or intermingled. 
   Flow into port  225  and exhaust from port  229 , the control of which is preferably but not mandatorily provided by at least one electrically controlled valve, causes a low pressure ram ( 280  visible in  FIGS. 4-6 ) to travel, and ultimately activate a high pressure valve (poppet valve  260 , visible in  FIGS. 4-6 ) Tied directly to the low pressure ram  280  is bolt  290 , which means bolt  290  will advance a paint ball  114  from the breech into a firing position within gun body  120 . Once the low pressure ram  280  has traveled sufficiently far to set the position of bolt  290 , a small additional motion will trigger the actuation of high pressure valve  260  within volumizer  240 . This in turn will release high-pressure gas which has been stored within volumizer  240  in a rapid burst, from where it will pass ultimately through bolt  290  and down the barrel. High pressure gas is admitted into volumizer  240  through one or more ports such as  243 ,  245 . Isolating the ports  243  and  245  are O-rings  244  and  246 . The O-rings  291 ,  292  found on bolt  290  serve to seal feed neck  110  from the blast of high pressure gas during firing, so that balls such as ball  112  within feed neck  110  are not blown away from gun body  120  or out of feed neck  110 . The remaining features numbered within  FIG. 2  pertain to volumizer  240 , the operation and construction which will be better explained herein below with reference to  FIG. 4 . 
     FIG. 3  illustrates valve assembly  200  from a projected view. This projected view, the side plan view  FIG. 2 , and the sectional views of  FIGS. 4-6  will be described together, with only limited reference to any specific figures. As already described with regard to  FIG. 2 , an isolated low-pressure system drives a low-pressure ram  280 , which in turn moves the sliding shaft and activates poppet valve  260 . More specifically, end cap  210  has a small protrusion  218  which, in combination with O-ring  219 , low pressure valve body  236 , ram head  282  and O-ring  284 , forms a variable volume low pressure enclosure  227 . As low-pressure gas is introduced into enclosure  227  through ports  121  and  225 , as illustrated by flow arrow  142  in  FIG. 4 , the volume of enclosure  227  will increase by driving ram head  282  farther from protrusion  218  in end cap  210 . Ram  280  is directly coupled to bolt  290 , thereby moving bolt  290  towards the position illustrated in  FIG. 5 . While not illustrated and the exact apparatus and method which are not consequential to the present invention, those skilled in the art will understand and recognize the myriad ways of coupling the output of a low-pressure regulator to port  121 , such as through an electric valve to a hose coupled into port  121 . The coupling which connects the hose into port  121  will commonly take the form of a small tube threaded at one end for screwing into port  121 , and barbed at the other to permit a hose to be slid thereon and not easily removed therefrom, though the particular means of coupling of pressurized gas is not critical to the performance of the present invention so long as the gas is in fact provided in a reliable manner. 
   While the volume of enclosure  227  is increasing, the volume of enclosure  237  is decreasing. In order to permit enclosure  237  to decrease in volume without increasing in pressure, gas retained therein is most preferably vented through an electrically controlled valve or the like to atmosphere. This arrangement has only a few limiting factors to how quickly ram  280  may be moved. A first limiting factor is how quickly the low pressure gas can be introduced into enclosure  227 . This is limited or in some instances controlled by the pressure of the low pressure gas at the ports  121 ,  225 , and the cross-sectional area and any flow restrictions in ports  121  and  225  and any other consequential flow restrictions between these ports and the source of low pressure gas. The preferred embodiment has no consequential flow restrictions between the ports and low pressure source, since the only items between the ports and gas tank are pressure regulators, which inherently only maintain pressure and thereby provide no consequential flow restriction, and the electric valve and hoses. The valve and hoses should be large enough to permit operation of ram  280  at any rate desired. 
   At any time, reversal of ram travel is achieved by applying gas from the low pressure source through ports  123 ,  229 , which pass through and into the interior of low-pressure housing  220  in enclosure  237 , on the side of ram  280  distal to end cap  210 . At the same time, gas within enclosure  227  will desirably be vented to atmosphere. This causes ram  280  to move towards end cap  210 , in turn resetting ram  280  and bolt  290  for the next firing sequence. Consequently, ram  280  travels in a linear path, simply reciprocating in direction controlled by the relative pressures between enclosures  227 ,  237 . 
   The high pressure gas flow is illustrated by arrows in  FIG. 6 , though the reference numerals described herein will be found on  FIGS. 2-4 . Volumizer  240 , best visible in  FIG. 3 , includes three distinct sets of holes or ports through which the high pressure gas will pass. One set are the high pressure inlets  243 ,  245  to the volumizer core. While two holes are visible in the figures, it will be understood that in the preferred embodiment, three are used and that any suitable number may be used. These holes are placed between each of the flow ports  247 - 249 . The exact number or size of high pressure inlets and flow ports are not critical to the operation of the invention, so long as there is an appropriate flow restriction induced by each for the appropriate function. These high pressure inlets  243 , 245  extend through the volumizer body from exterior to interior, and permit high pressure gas to pass from the high pressure regulator into volumizer  240  enclosure  257 . Like end cap  210  and low-pressure housing  220 , volumizer  240  does not move with respect to gun body  120 . Consequently, two O-rings  244 ,  246  are used to capture and isolate the high-pressure inlet to volumizer  240 . As aforementioned, angularly displaced from each high-pressure inlet  243 , 245 , and thereby completely isolated therefrom, are a plurality of flow ports  247 - 249 , best illustrated in  FIG. 3 . These flow ports  247 - 249  couple a flow path  258 , labeled in  FIG. 4  and formed between volumizer  240  wall  241  and gun body  120 , through volumizer  240  wall to bolt  290 . These flow ports  247 - 249  do not pass into the interior of the volumizer body, and instead only serve to port the high-pressure gas from the volumizer exterior flow path  258  to bolt  290 . 
   In operation, volumizer  240  is filled in enclosure  257  with high-pressure gas passing from the high-pressure regulator through port  125  in gun body  120  to ports  243 ,  245  in volumizer  240 , and from these ports into the volumizer enclosure  257 . The filling of enclosure  257  may occur at any time, so long as volumizer enclosure  257  is fully pressurized prior to being discharged. Said another way, the size of ports  125 ,  243 ,  245 , the pressure of the high-pressure source, and any other flow restrictions will control the amount of time needed to fully charge enclosure  257 . Consequently, in the preferred embodiment an electrically controlled valve is used to initiate the charge of volumizer enclosure  257  sufficiently in advance of firing to reach full pressure. This may in one embodiment occur at the same time low-pressure gas is being introduced into port  225 , though the timing may be different therefrom as desired or required. 
   Poppet valve  260  is initially closed, preventing escape of gas from volumizer enclosure  257 . Consequently, the exterior of volumizer  240 , defined by flow path  258 , is at atmospheric pressure, being coupled from the barrel through bolt  290 , and then through flow ports  247 - 249  formed in the volumizer wall that connect from bolt  290  to the volumizer wall  241  exterior However, when poppet valve  260  is opened, high pressure gas accumulated within volumizer enclosure  257  will be discharged through poppet outlet  251  into the space between the volumizer and gun body  120  defined by flow path  258 , which forms a passageway to the flow ports  247 - 249 . As already noted, these ports  247 - 249  pass from the volumizer exterior of wall  241  to immediately adjacent bolt  290 , all the while isolated within the wall of the volumizer from volumizer enclosure  257 . Then the gas passes through holes  294  in the bolt into the firing chamber. One of these holes is visible in  FIGS. 4-6  by cross-section, but the full plurality of holes  294  used in the preferred embodiment are best visible in  FIG. 3 . 
   The movement of ram  280  is used to drive bolt  290  forward past ball-retaining detent  126  and position paint ball  114  within the firing chamber, and simultaneously therewith, when bolt  290  is in proper position, to activate poppet valve  260 . As aforementioned, the O-rings  291 , 292  at either end of and circumscribing bolt  290  isolates the firing chamber from paint ball feed neck  110 , thereby preventing any passage of high pressure gas into the paint ball inlet passage. Consequently, all components are operated upon a single longitudinal axis, in line with the gun barrel, through a single sliding ram  280 . 
   In order to achieve this single-axis operation, poppet valve  260  has been located in the middle of valve assembly  200 , between the low-pressure housing  220  and bolt  290 . Such placement is in stark contrast to the prior art, where the poppet valve is placed at an end of the shaft and gun, and on a different axis from the barrel. The single-axis operation of the present invention is achieved by novel porting of the high pressure gas first into volumizer interior  257 , and then around volumizer wall  241 , using wall  241  to isolate flow ports  247 - 249  from the interior  257  of volumizer  240 . 
   Poppet valve  260  encompasses ram  280 . At the end of valve  260  adjacent enclosure  237 , an internal O-ring  262  seals ram  280  and valve hammer surface  261 , so that low-pressure or atmospheric pressure gas within enclosure  237  is isolated from either atmospheric or high-pressure gas found at the end of ram  280  adjacent to bolt  290 . External O-ring  264  similarly isolates enclosure  237  from either atmospheric or high-pressure gas found within poppet outlet  251 . Distal to valve hammer surface  261  is a spring  276  nested within volumizer cup  256 . Cup  256  in the preferred embodiment is supported upon a cup support shaft  255  extending from the end of volumizer  240  adjacent to bolt  290 , though the method of supporting cup  256  is not critical, and other suitable constructions or geometries may be used. 
   In order to best accelerate the travel of ram  280 , friction will desirably be kept at a minimum. In order to reduce friction, a small amount of initial movement of ram  280  away from end cap  210  releases the seal between O-ring  260  and ram  280 . This is enabled by the necked down region  289  in ram  280 , which with very little motion is adjacent to O-ring  260  and so not frictionally engaged therewith. 
   Spring  276  generates separation forces between cup  256  and spring sleeve  274 , which in turn presses against valve body  268 . Valve body  268  most preferably has a small flare  269  extending from cylindrical core  270 . Too large a flare will cause the surface area to be too great, and will consequently require the low pressure side undesirably be much closer in pressure to the high pressure source in order for the low-pressure ram  280  to generate more force than is being produced by the high pressure against valve body  268 . In order to prevent leakage between valve body  268  and supporting cup  256 , an O-ring seal  272  is provided. 
   When ram  280  is driven away from end cap  210 , it slides relatively unrestricted through valve  260 , only contacting therewith at O-ring  262 , and even then only for a very short distance of travel. Alignment of ram  280  while traveling is maintained through O-ring  284  engaging with low-pressure valve body  236  at the low-pressure end adjacent end cap  210 , and through O-ring  291  engaging with gun body  120  adjacent in feed  110 . Eventually, as illustrated in  FIG. 5 , top-hat shaped ram head  282  will be traveling at a relatively high rate of speed and will engage with valve hammer surface  261 . This position illustrated in  FIG. 5  is arrived at just prior to activation of valve  260 . 
   Any further motion, which is not only assisted by the low-pressure generated force but also by the momentum of ram  280 , will lead to movement of valve hammer surface  261  also away from end cap  210 . The movement of valve hammer surface  261  will lead to translation of valve body  268  and spring sleeve  274  as well, in turn compressing sleeve  274 . Most preferably, shoulder  238  against which O-ring  264  seats is sufficiently long along the axis of motion of ram  280  to ensure that the seal there between is maintained through the full movement of valve body  26 . 
   As valve body  268  is moved away from valve seat  234 , pressure is released from volumizer enclosure  257  into poppet outlet  251 . This release of pressure removes the force which had existed on valve body  268  which was opposing movement of ram  280 , leading to a sudden acceleration of both ram  280  and valve body  268 . In this way, there is ensured a rapid discharge of the pressurized gas within volumizer enclosure  257 . As the gas is discharged, it is passed through flow controlling surface  266 , which is preferably shaped for more smooth and laminar flow of air to maintain the efficiency of flow and improve the paint ball velocity at a given operating pressure. 
   This high-pressure gas discharge position is illustrated in  FIG. 6 , and the flow of the high pressure gas is illustrated by the inlet stream  144  and the subsequent flow path already detailed herein above. As also shown in  FIG. 6 , the low-pressure inlet flow  142  is still open, maintaining the position of ram  280  against the force of spring  276 . While spring  276  is not strictly required, the inclusion of this spring adds a certain amount of “pop” to the return motion of ram  280  after firing, due to the release of stored mechanical energy in the compression of spring  276 . This “pop” or quick acceleration can occur more quickly than the initial building of gas pressure within enclosure  237 , which pressure will preferably be timed to occur at such a time as to induce motion of both ram  280  and valve  260  back towards end cap  210 , starting after the proper discharge of high pressure gas from within enclosure  257 . 
   In accord with the teachings of the present invention, the preferred valve assembly  200  is manufactured as a number of discrete parts that are assembled into a single, modular component. The entire valve assembly  200  is held in place within gun body  120  by an anchoring screw passing through hole  214  in wing  212  into gun body  120 . End cap  210  is rigidly coupled and aligned with low-pressure ram chamber  220  via one or more alignment pins  216  which are rigidly affixed to end cap  210  and which pass through an alignment hole formed in low-pressure ram chamber  220 , as is visible in  FIGS. 3-6 . To securely fasten end cap  210  to low-pressure ram chamber  220 , each alignment pin  216  is provided with a neck  217  into which a set screw  222  will engage. By proper shaping of neck  217 , tightening of set screw  222  will draw end cap  210  tight against low-pressure ram chamber  220 . Low-pressure ram chamber  220  couples with volumizer  240  through an external set of threads that thread into internally threaded volumizer flange  242 . Finally, bolt  290  is threaded onto the threaded end  286  of ram  280 . 
   A combination of as many relatively large holes  294  as possible and an extended bore  296  reduce the material and consequently the mass of bolt  290 . Similarly, the diameter of ram  280  and total size of ram head  282  are kept to a minimum, likewise reducing the total mass. These reductions in mass reduce the time required to move ram  280  and bolt  290  in the reciprocal manner required for the operation of gun  100 , thereby increasing the maximum attainable firing rate. In addition, the lower mass facilitates the ready handling and rapid movement of gun  100 . In addition to the amounts of materials used being kept to a minimum, the selection of lighter and stronger materials will also enable reduced mass. 
   As a result of the preferred embodiment valve assembly  200 , a gun may be manufactured and assembled in a very modular fashion. Further, since the preferred ram  280  is isolated from high pressures and the preferred poppet assembly is balanced, activation can be very rapid, a feature which is very desirable in modern paint ball guns. 
   While the preferred embodiment valve assembly  200  is inserted directly into a bore within gun body  120 , it is also contemplated herein to provide a separate sleeve which serves the functions of gun body illustrated in  FIGS. 4-6 , which would in turn be mounted within a gun body. In either case, valve assembly  200  unifies the working components into a single, well controlled and readily replaced unit. This combined assembly not only simplifies gun maintenance and repair, but also reduces the space required for this combination of components into a single in-line assembly taking up no more space than a prior art bolt without valve. 
   While the foregoing details what is felt to be the preferred embodiment of the invention, no material limitations to the scope of the claimed invention are intended. Further, features and design alternatives that would be obvious to one of ordinary skill in the art are considered to be incorporated herein. The scope of the invention is set forth and particularly described in the claims herein below.