Patent Publication Number: US-7900622-B2

Title: Paintball marker with user selectable firing modes

Description:
RELATED APPLICATIONS 
     This application is a continuation-in-part application of U.S. application Ser. No. 12/016,370, filed Jan. 18, 2008, which claimed priority to U.S. Provisional Application Ser. No. 60/880,989, filed on Jan. 18, 2007, the entire disclosures of which are hereby incorporated by reference. This application also claims the benefit of U.S. Provisional Application Ser. No. 60/942,144, filed on Jun. 5, 2007, the entire disclosure of which is hereby incorporated by reference. 
    
    
     TECHNICAL FIELD 
     The present invention relates generally to paintball markers, and like devices for firing frangible projectiles. 
     BACKGROUND 
     Paintball is a popular sport in which opposing sides attempt to seek out and “shoot” one another with paintballs. Players use paintball markers (also known as paintball guns) to propel the paintballs with compressed gas or combustible fuel. The paintballs are designed to break upon impact and leave a visible mark. 
     Since paintball games often simulate combat, paintball markers that resemble military equipment are desirable to increase the realism of the experience. For example, paintball markers have been modified to resemble assault rifles, sniper rifles, etc. In some cases, however, such modifications can be difficult to install and remove. Moreover, the modifications may detract from the marker&#39;s functionality and reliability. 
     SUMMARY 
     According to one aspect, the invention provides a paintball marker with a barrel that is coupled to a receiver. A valve arrangement is provided to selectively vent gas to propel projectiles through the barrel responsive to actuation of a firing mechanism. The marker may include a tool box that is capable of being coupled with the receiver. Typically, the tool box resembles a magazine that feeds projectiles into the receiver. For example, the tool box could resemble an M-16 or AK-47 style magazine. In some embodiments, the tool box includes a storage compartment configured to hold one or more items for maintaining the marker. 
     According to another aspect, the invention provides a tool box for use with a paintball marker. The tool box may have a body with a proximate end capable of being detachably coupled with a receiver of a paintball marker and a distal end. In some embodiments, the body defines a storage compartment configured to hold one or more items for maintaining the marker. 
     Additional features and advantages of the invention will become apparent to those skilled in the art upon consideration of the following detailed description of the illustrated embodiment exemplifying the best mode of carrying out the invention as presently perceived. It is intended that all such additional features and advantages be included within this description and be within the scope of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The following description references the attached drawings which were given as non-limiting examples only, in which: 
         FIG. 1  is a perspective view of an example paintball marker constructed according with an embodiment of the present invention; 
         FIG. 2  is an exploded view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 3  is a left side view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 4  is a detailed view of the grip assembly for paintball marker shown in  FIG. 1 ; 
         FIG. 5  is a right side view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 6  is a rear view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 7  is a front view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 8  is a top view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 9  is a bottom view of the example paintball marker shown in  FIG. 1 ; 
         FIG. 10  is a detailed perspective view of the forestock shown in the example paintball marker of  FIG. 1 ; 
         FIG. 10A  is an exploded view of the forestock shown in  FIG. 10 ; 
         FIG. 11  is a detail perspective view of an alternative forestock that may be used with the example paintball of  FIG. 1 ; 
         FIG. 12  is a perspective view of an example tool box constructed in accordance with the embodiment of the invention in which the tool box is in an open position to show items disposed therein; 
         FIG. 13  is a side cross-sectional view showing the first and second supply lines in the example paintball marker of  FIG. 1 ; 
         FIG. 14  is a side cross-sectional view showing the second supply line portion of the example paintball marker shown in  FIG. 1 , with an example rear stock attached to the marker; 
         FIG. 15  is a cross-sectional view of the example paintball marker shown in  FIG. 14 , with a cross-sectional view of an example rear stock attached to the marker; 
         FIG. 16  is a cross-sectional view of the example paintball marker shown in  FIG. 15 , with the rearstock detached from the marker; 
         FIG. 17  is a detailed perspective view of a portion of a receiver according to an alternative embodiment; 
         FIGS. 18A-18C  show example rear stocks that may be attached to the marker; 
         FIGS. 19A-19E  show example forestocks that may be attached to the marker; 
         FIGS. 20A-20E  show example tool boxes that resemble magazines; 
         FIGS. 21A-21D  show example front sights and handles that may be connected to the marker; 
         FIG. 22  shows an example vertical handle that may be connected to the marker; 
         FIG. 23  shows an example grip assembly according to an alternative embodiment; 
         FIG. 24  shows a cross-sectional view of the example grip assembly of  FIG. 23 ; 
         FIG. 25  is a detailed cross-sectional view of the example grip assembly; 
         FIG. 26  is a detailed cross-sectional view of the grip assembly; and 
         FIG. 27  is a schematic view showing possible inputs and outputs for the controller. 
     
    
    
     Corresponding reference characters indicate corresponding parts throughout the several views. The exemplifications set out herein are illustrative, and are not to be construed as limiting the scope of the invention in any manner. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
       FIGS. 1-9  illustrate an example paintball marker  100  constructed according to an embodiment of the present invention. The invention could be implemented in a manual, semi-automatic, or automatic marker, even though a semi-automatic marker is shown for purposes of illustration. It should be appreciated that the marker  100  could use a variety of propellants to propel paintballs (or other projectiles) from the marker  100 . The term “propellant” is broadly intended to encompass both compressed gas, such as carbon dioxide and nitrogen, as well as combustible fuel, such as propane, butane, and methylacetylene-propadiene (“MAPP”). 
     In the example shown, the marker  100  includes a barrel  102  through which projectiles may be propelled. As shown, the barrel  102  is coupled with a receiver  104 , which defines an interior cavity dimensioned to house internal components of the marker  100 . As used herein, the term “coupled” is broadly intended to encompass both direct and indirect connections. Typically, the barrel  102  includes external threads that may be received by internal threads in the receiver  104 . By way of other examples, the barrel  102  may attach to the receiver  104  with an interference fit, frictional fit, or unitary formation. The receiver  104  may be formed from a variety of materials, such as aluminum, stainless steel, magnesium, or composites. In embodiments in which the receiver  104  is made of magnesium, it has been found that the production molds last substantially longer than that of aluminum. In some embodiments, the receiver  104  may have a clamshell-type body. 
     In the embodiment shown, the marker  100  includes a forestock  106 . As best seen in  FIGS. 10 and 10A , the forestock  106  may include a bore  107  dimensioned to receive the barrel  102 . Preferably, the forestock  106  may be detachably coupled to the receiver  104 . In the example shown, a first pin  108  and a second pin  110  extend through holes  111  in the forestock  106  and holes  113  in the receiver  104  ( FIG. 2 ), thereby coupling the forestock  106  to the receiver  104 . In this example, the forestock  106  may be detached from the receiver  104  by removing the pins  108  and  110  and sliding the forestock  106  off the barrel  102 . Conversely, a user may mount the forestock  106  to the marker  100  by sliding the forestock  106  over the barrel  102  such that the holes  111  in the forestock  106  and the holes  113  in the receiver  104  are aligned. The pins  108  and  110  may then be moved through the forestock  106  and receiver  104  to couple the forestock  106  to the receiver  104 . As best seen in  FIG. 7 , the pins  108  and  110  may include a bias member  105  to prevent accidental removal of the pins  108  and  110 . Although the first pin  108  and second pin  110  are shown for purposes of illustration, it should be appreciated that other quick connections may be used to couple the forestock  106  to the receiver  104 . 
     In some cases, the forestock  106  may be associated with a barrel adapter  109 . The barrel adapter  109  (best seen in  FIG. 10A ) allows a user to configure the marker  100  with barrels of different diameters. Consider a situation in which a user desires to use barrels with either a ⅞ inch diameter or a 1 inch diameter. The bore  107  could be dimensioned to receive the 1 inch barrel. If the ⅞ inch barrel is desired to be used, the user would place the barrel through the adapter  109 . In this example, the opening in the adapter  109  would be dimensioned to receive the barrel, which is ⅞ inches in this example. The outer diameter of the adapter  109  would be dimensioned to be received by the bore  107 , or 1 inch in this example. As shown, the adapter is received in a recess  115  formed in the forestock  106 . 
     In some embodiments, the forestock  106  may include a bottom rail  112 , a side rail  114 , and/or a top rail  116  for mounting accessories, such as sites, scopes, etc. In the example shown, the marker  100  includes a front site  118  mounted to the top rail  116 . It should be appreciated that the marker  100  could be customized with other types of sites, such as those shown in  FIGS. 21A-21B . By way of a further example, a vertical handle, such as shown in  FIG. 22 , could be attached to the bottom rail  112 . 
     Preferably, the user may select between a plurality of interchangeable forestocks, which each allow a suitable quick connection with the receiver  104  to customize the marker  100 . For example, if the receiver  104  includes holes  113 , each of the forestocks could include holes  111  to allow a quick connection using pins  108  and  110 . Example forestocks that could be used with the marker  100  are illustrated in FIGS.  19 A- 19 E. It should be appreciated that other styles of forestocks could be used with the marker  100 . 
     In some embodiments, the marker  100  may include a tool box  120  for storing one or more items. In this embodiment, the tool box  120  is coupled with and extends from the receiver  104 . Typically, the tool box  120  is detachably coupled with the receiver  104 ; however, the tool box  120  could be integral with or permanently affixed to the receiver  104 . Embodiments are also contemplated in which the tool box  120  could be an internal storage compartment in the receiver  104  that could be accessed by a user. 
     Preferably, the tool box  120  resembles a magazine that feeds projectiles into the receiver. Instead of feeding projectiles into the receiver  104 , however, the tool box  120  would typically hold tools for maintaining the marker  100 , including but not limited to hex wrenches or a tube of oil. As shown, the tool box  120  includes a slot  122  dimensioned to receive a first supply line  124 . In other embodiments, the tool box  120  could include a connection for coupling the first supply line  124 . Preferably, the first supply line  124  provides a source of compressed gas for a valve arrangement  178  within the marker  100  (see  FIG. 13 ). In some cases, if the marker  100  were a combustible fuel powered marker, the first supply line  124  may provide a supply of fuel, such as propane, to a combustion chamber within the marker  100 . 
     The tool box  120  may include an internal storage compartment for storing items, such as tools. In the example shown in  FIG. 12 , the tool box  120  includes a first side  130  and a second side  132  pivotally coupled with a bottom  134 . Although the embodiment shown includes an open top, the tool box  120  may be entirely closed since projectiles are not fed into the receiver  104  from the tool box  120  in this embodiment. 
     As shown, the tool box  120  includes a first hinge  136  and a second hinge  138  that allow the first side  130  and second side  132  to pivot, respectively. In this example, the hinges  136  and  138  are living hinges, but separate hinges could be coupled with the sides  130  and  132  and bottom  134  in some cases. It should be appreciated that other pivotal connections could also be used. Although this example shows the tool box  120  hinged at the bottom  134 , it should be appreciated that the tool box  120  could be hinged at the sides  130  and  132  or the top or not hinged at all. 
     In some cases, the tool box&#39;s  120  interior may include tool holders configured to receive a specific arrangement of tools (or other items). In the example shown, the tool box  120  includes slots  140  dimensioned to receive hex wrenches  142  in the first side  130  of the tool box  120 . The second side  132  includes complementary ridges  144  configured to close the slots  140  when the tool box  120  is closed, thereby holding the wrenches  142  in place. In this example, the first side  130  of the tool box  120  also includes an area for a tube of oil  146  that could be used to maintain the marker  100 . It should be appreciated that the internal cavity of the tool box  120  could be configured to hold a variety of tools, accessories, or other items. 
     In the example shown, the tool box  120  includes an opening  143  dimensioned to receive an internal latch  145  when the tool box  120  is closed. In this example, the tool box  120  includes an opening  147  dimensioned to receive a latch mechanism in a tool box mount  121  for detachably coupling the tool box  120  to the receiver  104 . 
     Referring again to  FIGS. 1-9 , the marker  100  preferably includes a tool box mount  121  configured to receive the tool box  120 . As shown, the tool box mount  121  includes a release button  123  (best seen in  FIG. 5 ) that controls a latch mechanism associated with the tool box mount  121 . In the example shown, the latch mechanism engages the opening  147  in the tool box  120  to selectively release the tool box  120  from the tool box mount  121 . It should be appreciated that a variety of mechanisms could be used to detachably couple the tool  120  with the tool box mount  121 , such as an interference fit, frictional fit, magnets, etc. 
     In the example shown (as best seen in  FIG. 2 ), the tool box mount  121  is coupled with the receiver  104  using an interference fit. As shown, the receiver  104  includes ridges  129  that extend from the receiver  104 . The top portion of the tool box mount  121  includes grooves  125  formed in a flange  127  that are configured to receive the ridges  129 . To couple the tool box mount  121  to the receiver  104 , the user would align the grooves  125  with the ridges  129 , such that the ridges  129  extend through the grooves  125 . The tool box mount  121  may then be moved toward the barrel  102  in the example shown such that the flange  127  creates an interference fit with the ridges  129 . The user may detach the tool box mount  121  by moving the tool box mount  121  in an opposite direction (away from the barrel  102  in this example) until the ridges  129  are aligned with the grooves  125 . Other mechanisms, such as a frictional fit, could also be used to couple the tool box mount  121  with the receiver  104 . 
     Preferably, a plurality of interchangeable tool boxes and tool box mounts may be provided to allow customization of the marker  100 . Typically, each of the tool boxes includes an interior cavity for storing items, such as tools. Examples of tool boxes that resemble magazines of types used for feeding projectiles into the receivers of actual firearms are shown in  FIGS. 20A-20E . It should be appreciated that other styles could also be provided. The tool box  120  may be formed from a variety of materials, including but not limited to plastic, aluminum and magnesium. 
     The marker  100  may include a grip assembly  146 . In the example shown, the grip assembly  146  includes a grip  148  that is dimensioned for a user to grasp. The grip assembly  146  includes a trigger  150  for actuation by the user to fire the marker  100 . The trigger  150  may mechanically and/or electrically selectively fire the marker  100 . In the example shown, the trigger  150  is surrounded by a trigger guard  152 . As shown, the marker  100  includes a safety  154 . In the position shown in  FIG. 1 , the safety  154  prevents the marker  100  from firing; if moved to a fire position, the safety  154  allows the marker  100  to fire projectiles. Although the example shown includes a lever for actuating the safety  154 , it should be appreciated that other forms of safety could be used. 
     In some embodiments, the grip assembly  146  may be detachably coupled with the receiver  104 . As shown, the grip assembly  146  includes a hole  155  that is alignable with a hole  157  in the receiver  104  through which a pin  156  may be received. By removing the pin  156  (and the lower pin  170 ), the grip assembly  146  may be detached from the receiver  104 . In the example shown, the lower portion of the grip  148  includes an adaptor  158  configured to receive a propellant source, such as a canister of carbon dioxide or nitrogen. As discussed below, the adaptor  158  and first supply line  124  are optional, depending on whether the rear stock attached to the receiver  104  includes an internal passageway  186  for connection to a propellant source (See  FIGS. 15-16 ). 
     In the example shown, a picatinny rail  160  is attached to a top portion of the receiver  104 . The picatinny rail  160  may be used to add risers, sites, handles, or other items to the receiver  104 . As shown, a rear sight  161  is coupled to the picatinny rail  160 . By way of another example, carry handles, such as shown in  FIGS. 21C-21D , could be mounted to the picatinny rail  160 . 
     In the embodiment shown, the marker  100  includes a hopper  162  for holding a plurality of projectiles to be fired. As shown, the hopper  162  includes a lid  164  pivotably mounted to the hopper  162  to selectively open/close an opening to the hopper  162 . Preferably the hopper  162  has a low profile to reduce the target area of the user and allow a better line of site to fire the marker  100 . By way of example only, the hopper  162  may have a length that is more than three times its height in some cases (see  FIG. 3 ). As shown, the hopper  162  is offset from the receiver  104  to allow a better line of site for the user to fire the marker  100 . However, the hopper  162  could be coupled to the receiver  104  on the top (e.g., picatinny rail  160 ) or other location of the receiver  104 . 
     In some cases, the hopper  162  may be coupled with a feed mechanism  166  that feeds projectiles into the receiver  104 . An example feed mechanism that could be used with the marker  100  is shown in U.S. Pat. No. 6,739,323, which is incorporated herein by reference. 
     Instead of a separate feed mechanism, the hopper  162  may include an integral feed mechanism in some embodiments. For example, the hopper  162  may be an agitating or force-fed hopper. In some cases, the projectiles may be gravity fed into the receiver  104 . For example, the lower portion of the hopper  162  may include a passage that is coupled directly with the receiver  104 , so that projectiles may be fed one-by-one through the passage into the receiver  104 . In some embodiments, the receiver  104  (or other portion of the marker  100 ) may include an internal cavity for receiving a plurality of projectiles. By way of another example, the receiver  104  may be stick fed with projectiles. 
     In the embodiment shown in  FIGS. 1-9 , the marker  100  includes a detachable end cap  168 . If the user desires to have a rear stock, the end cap  168  may be removed and a rear stock coupled to the receiver  104  (see  FIGS. 14-16 ). In the example shown, pins  170  pass through projections  172  (see  FIGS. 2 and 13 ) in the end cap  168  and holes in the receiver  104  and grip assembly  146 . Removal of the pins  170  allows the user to detach the end cap  168  from the receiver  104 . In the example shown, the end cap  168  includes an optional ring  174  that user may grasp to remove the end cap  168 . As discussed below, a plurality of interchangeable rear stocks may be substituted for the end cap  168  to customize the marker  100 . Preferably, each of the rear stocks include similarly arranged holes such that the rear stocks may be attached to the receiver  104  using the pins  170 . Examples of rear stocks that could be used with the marker  100  are shown in  FIGS. 18A-18C . 
     Referring now to  FIG. 13 , there is shown a detailed cross-sectional view of the marker  100 . As shown, a sear  188  is interposed between the trigger  150  and a  190 . In this example, the sear  188  is disposed on pivot pin  192  and is biased by spring  194  toward engagement of the rear bolt  190 . When the marker  100  is in the cocked position, actuation of the trigger  150  releases the rear bolt  190  from the sear  188 . In the example shown, the marker  100  is in the cocked position when the rear bolt  190  is in a rearward position in which the sear  188  prevents forward movement of the rear bolt  190 . In the example shown, the marker  100  moves to a discharge position by releasing of the rear bolt  190  from the sear  188  due to user actuation of the trigger  150 . It should be appreciated that other trigger assemblies, both mechanical and electrical, may be suitable to selectively fire the marker  100  and are contemplated herein. 
     In the example shown, the rear bolt  190  moves under the bias of drive spring  196  upon actuation of the trigger  150 . A pin  198  is disposed within the spring  196  in the example shown. The rear bolt  190  is coupled to a front bolt  200  via a linkage arm  202  in the example shown. This causes concomitant movement of the front bolt  200  with the movement of the rear bolt  190 . The front bolt  200  is adapted to push a projectile into the barrel  102  during firing. 
     The bias of drive spring  196  on rear bolt  190  causes rear bolt  190  to depress an impact pin  204  on the valve assembly  178 , which causes the valve assembly  178  to release a quantity of compressed gas, thereby causing a projectile to be propelled out the barrel  102 . Another quantity of compressed gas may be released on the side of valve assembly  178  in which the rear bolt  190  is disposed, which will recoil the rear bolt  190  to the cocked position. Example valve arrangements and firing mechanisms that could be used are shown and described in U.S. Pat. Nos. 4,189,609, 5,722,383, and 6,550,468, which are each hereby incorporated by reference. 
     In the embodiment shown, a second supply line  176  can be seen. Preferably, the marker  100  may be configured such that either the first supply line  124  or the second supply line  176  may supply the valve arrangement  178  with a propellant with which the projectiles may be fired. Preferably, the first supply line  124  or the second supply line  176  provides compressed gas, such as carbon dioxide or nitrogen, to the valve arrangement  178 . As discussed above, however, the supply lines  124  or  176  could provide fluid communication with a supply of combustible fuel in some embodiments. 
     In this example, the marker  100  includes a coupling  180  associated with the first supply line  124 . Typically, the user would choose between the first supply line  124  and the second supply line  176 . If the user decided to use the first supply line  124 , the user would put the first supply line  124  and coupling  180  associated with the first supply line  124  into the receiver. This would supply compressed gas to the valve arrangement  178  via the first supply line  124 . A passageway is defined in the receiver  104  for receiving the second supply line  176 . Preferably, the passageway extends from the valve arrangement to the rear portion of the receiver  104  so that the second supply line  176  may be aligned with a passage with a rear stock which is in fluid communication with a supply of compressed gas. If the user desired to use the second supply line  176 , the first supply line and associated coupling  180  would typically be removed and the second supply line and an associated coupling  180  inserted into the passageway. The coupling  180  provides the valve arrangement  178  with a supply of compressed gas from the first supply line in the example shown. 
     In some cases, the coupling  180  may be configured to receive both the first supply line  124  and the second supply line  176 . For example, the coupling  180  may include a first check valve (not shown) at the inlet of the first supply line  124  into the coupling  180  and a second check valve (not shown) at the inlet of the second supply line  176  into the coupling  180 . With this arrangement, the inlets would only be open due to the supply of compressed gas to open a respective check valve. It should be appreciated that other mechanisms, both mechanical and electrical, could be used to selectively supply the valve arrangement  176  with a flow of compressed air from either the first supply line  124  or the second supply line  176 . In some embodiments, the coupling  180  could be configured to supply compressed air from both the first supply line  124  and the second supply line  176 . In the example shown in  FIG. 13 , the second supply line  176  does not supply compressed gas to the valve arrangement  178  due to the end cap  178  being connected to the receiver  104 . As discussed below, the second supply line  176  may continue flow through the rear stock, which may be connected with a source of compressed gas. 
       FIG. 14  shows an example in which a rear stock  182  has been coupled with the receiver  104 . In the example shown, the rear stock  182  includes a projection  184  with holes dimensioned to receive the pins  170 . Accordingly, a user may customize a marker  100  with a plurality of interchangeable rear stocks that may be coupled to the receiver  104 . Examples of rear stocks that may be coupled to the marker  100  are shown in  FIGS. 18A-18C . It should be appreciated that other types of rear stocks could also be provided. 
       FIGS. 15-16  show the example embodiment of  FIG. 14  with the rear stock  182  shown in sectional view. As shown, the rear stock  182  includes a passageway  186  that is in fluid communication with the second supply line  176 . The passageway  186  may be in fluid communication with the supply of compressed gas (or other propellant), thereby providing compressed gas to the valve arrangement  178 . In some cases, the rear stock  184  may include a recess  205  for receiving an end of the pin  198 . 
       FIG. 17  shows the right half of an example receiver  104 . Although the example receiver  104  shown includes holes that could be used for quick connections of rear stocks, fore stocks, etc., this receiver  104  could also be used with a marker without such customization features. In some cases, the valve assembly  178  may be tapped to supply compressed gas for other functions associated with the marker  100 . For example, the feed mechanism  166  could be pneumatically actuated with compressed gas tapped off the valve assembly. For example, U.S. Pat. No. 6,739,323 shows a feed mechanism that may be pneumatically actuated. By way of another example, U.S. Pat. No. 6,550,468 shows a trigger assist that may be pneumatically actuated, In receivers formed by two halves that are connected together, such as the example half shown, gas that is tapped off the valve assembly  178  tends to escape through the seam between the halves of the receiver  104 . 
     In the example shown, the receiver  104  includes a groove  206  dimensioned to receive a seal  208 , such as an O-ring. Preferably, the groove  206  is substantially elliptical is shape, which retains the seal  208  without a fastener or adhesive. The groove  206  and seal  208  are disposed within the receiver  104  preferably adjacent the portion of the valve assembly  178  that is tapped to prevent escape of gas through the seam in the receiver  104 . As shown, a first outlet port  210  and a second outlet port  212 , which are associated with tapped portions of the valve assembly  178 , are disposed within the groove. Additionally outlet ports (or a single outlet port) may be provided. 
       FIGS. 23-27  show a grip assembly  214  according to an alternative embodiment, which uses electronics (at least in part) to actuate firing of the marker  100 . Referring to  FIG. 23 , the grip assembly  214  includes a grip  216  that is dimensioned for a user to grasp. As discussed below, the electronics (and related components) for controlling actuation of the marker  100  are disposed within the grip  216 . The grip assembly  214  includes a trigger  218  for actuation by the user to fire the marker  100 . In the example shown, the trigger  218  is surrounded by a trigger guard  220 . As shown, the lower portion of the grip  216  includes an adaptor  222  configured to receive a propellant source, such as a canister of carbon dioxide or nitrogen. As discussed above, the adaptor  222  may be optional, depending on the type of rear stock attached to the receiver  104 . 
     In this example, the grip  216  includes a battery door  224  that may be removed to provide access to a battery associated with the electronics (and possibly other components internal to the grip  216 ). Although the battery door  224  extends longitudinally along the rear portion of the grip  216  in the example shown, it should be appreciated that the battery door  224  could be located elsewhere on the grip  216  depending on the circumstances. As shown, the battery door  224  includes a clasp  226  for detachable coupling with the battery door  224 . It should be appreciated that other mechanisms could be used for selectively opening/closing the battery door  224  to the rear portion of the grip  216 . 
     In the embodiment shown, the grip assembly  214  includes a mode selector  226  for selecting among multiple firing modes. The term “firing mode” is intended to be broadly construed to include a safety position in which the marker  100  is prevented from firing, as well as modes that in the marker  100  are allowed to fire. In this example, the mode selector  226  includes a lever  228  for rotating the mode selector  226  between different firing modes. In the example shown, a mode indicator  230  aligns with the selected firing mode. As shown, the mode indicator  230  specifies that a first mode  232  is selected. By rotating the mode selector  226 , a second mode  234  or a third mode  236  could be selected. As shown, an end of the lever  228  defines an opening  238  for receiving detents  240  to retain the mode selector  226  in the selected mode. Although a rotary mode selector  226  is shown for purposes of example, it should be appreciated that other non-rotating mode selectors, such as a linearly-moving lever, could be used. Although the embodiment shown includes three modes, it should be appreciated that embodiments are contemplated with only two modes; additionally, embodiments are contemplated with more than three modes. 
       FIGS. 24-26  show cross-section views of the example grip assembly  214  shown in  FIG. 23 . Unlike the embodiment described previously with respect to  FIG. 13 , there is no contact between the trigger and sear in the embodiment shown. Instead, a controller circuit electronically detects movement of the trigger and actuates movement of the sear to fire the marker  100 . In some embodiments, the manner by which the controller circuit controls movement of the sear could depend upon the firing mode and/or other firing characteristics selected by the user. 
     In the embodiment shown, a sear  242  pivots about a pivot pin  244  and the rear section (right portion in  FIG. 24 ) is urged upward (in this example) by a biasing member  246 . A depending portion  248  of the sear  242  extends toward a position adjacent a linear actuator  250 , such as a solenoid. In the embodiment shown, the depending portion  248  is unitary with the sear  242 ; however, embodiments are contemplated in which the depending portion  248  and the sear  242  could be separate components that are coupled together. As shown, a rod  252  of the linear actuator  250  moves between a retracted position and an extended position (shown). When the rod  252  moves to the extended position, this pushes the depending portion  248  away from the linear actuator  250 , which rotates the sear  242  (clockwise as shown) to fire the marker  100 . For example, this movement of the sear  242  could release the rear bolt  190 , which causes firing of the marker  100 . In other embodiments, such as using combustible gas, this movement of the sear  242  could be used to initiate ignition in a combustion chamber. 
     A controller  254  controls movement of the rod  252  responsive to movement of the trigger  218 . The controller  254  could be a microcontroller, for example, that is programmed to perform the functions described herein. Other electronic components, such as a capacitor  255 , could be associated with the controller.  FIG. 27  is a simplified schematic representation showing possible inputs and outputs for the controller  254 , according to an embodiment, which will be described below. 
     Referring again to  FIGS. 24-26 , the controller  254  determines when the trigger  218  is pulled by using one or more proximity sensors to detect the position of the trigger  218 . Although the embodiment described below uses magnetic sensors, embodiments are contemplated in which other types of proximity sensors could be used, including but not limited to optical sensors, capacitive sensors, and inductive sensors. 
     In the example shown, a magnet  256  is associated with the trigger  218  that moves concomitant with the trigger  218 . As shown, the magnet  256  is embedded in the trigger  218 ; however, embodiments are contemplated in which the magnet could be coupled with the trigger  218 , such as using a fastener or adhesive. One or more magnetic sensors, such as Hall effect sensors, may be provided to detect the trigger&#39;s  218  position by detecting the magnetic flux associated with the magnet  256 . 
     For example, in the embodiment shown, the magnet  256  is oriented to move between a first trigger detector  258  and a second trigger detector  260  when the trigger is pulled (as best seen in  FIG. 26 ). With this arrangement, the controller  254  actuates the rod  252  to the extended position when both the first trigger detector  258  and the second trigger detector  260  sense the magnetic field of the magnet  256 . Typically, the first trigger detector  258  and the second trigger detector  260  are Hall effect sensors. With such an arrangement, the trigger detectors  258  and  260  will switch on (output changing from low to high or visa versa) when the magnetic flux density increases above a threshold level, which indicates to the controller  254  that the trigger  218  has been pulled. In response, the controller  254  will actuate the rod  252  to the extended position, thereby moving the sear  242 . When the magnetic flux density decreases below a threshold level, the trigger detectors  258  and  260  will switch off (output changing from high to low or visa versa), which indicates to the controller  254  that the trigger  218  has been released. The controller  254  will move the rod  252  to the retracted position. Typically, the rod  252  is held in the extended position for a pre-determined period of time, not dependent on the amount of time the trigger  218  is pulled. 
     In some embodiments, at least one of the first trigger detector  258  and the second trigger detector  260  are unipolar Hall effect sensors. By using a unipolar Hall effect sensor, safety advantages are provided because a specific magnetic orientation would be required to fire the marker  100 , which reduces the possibility that external magnets would inadvertently cause the marker  100  to fire. For example, consider an example in which the first trigger detector  258  is a unipolar Hall effect sensor that switches on in response to a south pole and the second trigger detector  260  is an omnipolar Hall effect sensor that switches on in response to either a north pole or a south pole. In this example, the magnet  256  would be oriented on the trigger  218  such that the south pole would be exposed to the first trigger detector  258  when the user pulls the trigger  218 . With this type of arrangement, the magnet  256  could include a pole indicator printed on a side, such as text or a graphic, for maintenance purposes if the user needed to replace the magnet  256  so that the correct orientation could be determined. 
     In some embodiments, a magnet  262  is associated with the mode selector  226  that moves concomitant with rotation of the mode selector  226 . The magnet  262  may be embedded in the mode selector  226  coupled with the mode selector  226  using a fastener, adhesive, or otherwise associated with the mode selector  226 . In the embodiment shown, a mode detector  263  is provided to detect the position of the mode selector  226 . For example, the mode detector could be a magnetic sensor, such as a Hall-effect sensor, to detect the mode selector&#39;s  226  position by detecting the magnetic flux associated with the mode selector  226 . This allows the controller  254  to determine the firing mode selected by the user. Other embodiments are contemplated in which other types of electronics could be used to select the firing mode, including but not limited to tactile switches, optical-electronics, momentary switches, push-button switches, rotary switches, and capacitive sensors. 
     In the embodiment shown, the grip assembly  214  includes a user interface  264  and a status indicator  266  on an end of the grip  216  opposite the battery door  224 . As shown, a first opening  268  provides access to the user interface  264 , while a second opening  270  exposes the status indicator  266 . In the example shown, the user interface  264  is a momentary push-button switch; however, other embodiments are contemplated in which other suitable switches, knobs, etc., could be used. Although the status indicator  266  will be described herein as a LED with multiple colors (e.g., red/green/orange), it should be appreciated that other mechanisms, such as audible alerts, a LCD display, etc., would be suitable to provide information to the user regarding the marker  100 . 
     The user interface  264  allows the user to turn off the electronics. For example, pushing the user interface  264  for greater than a specific time, such as two seconds, could turn off the electronics. The status indicator  266  could be used to let the user know that the electronics is turned off. For example, the status indicator could light up red when the user has pushed the user interface for a sufficient period to turn off the electronics. 
     Additionally, the user interface  264  can be used to adjust the manner by which the marker  100  fires. For example, the user interface  264  could allow the user to select the default firing mode associated with modes  234  and  236 . Consider an example in which the user pushes the user interface  264  for approximately 0.5 seconds (or another predetermined time) and releases the user interface  264 , then the status indicator  266  starts flashing orange (or other color). In this example, the status indicator could flash a number of times corresponding with default firing mode. By way of example only, the firing modes could be: (1) safe three-round burst—pulling the trigger three times in less than a second will result in a 3-shot burst; (2) safe full-auto—pulling the trigger three times in less than a second will result in full-automatic firing; (3) auto-response—firing upon both pulling and releasing the trigger; (4) turbo mode—pulling the trigger three times in less than one second will result in full-automatic firing at a rate of 15 bps (or other predetermined rate); (5) semi-auto—firing each time the trigger is pulled. In this example, the user will know that the marker  100  is set to the safe full-auto mode as the default firing mode if the status indicator  266  flashes twice. It should be appreciated that the firing modes listed above are provided for example purposes only and are not intended to limit the types or number of firing modes that could be used. 
     In some embodiments, the user can change multiple characteristics by which the marker  100  fires. Consider an example in which four characteristics of the marker  100  could be changed: (1) dwell—the amount of time that the linear actuator  250  is powered during a trigger pull; (2) debounce—the minimum amount of time between accepted trigger pulls; (3) rate-of-fire; and (4) default firing mode. By way of example only, the user could enter a programming mode to change one or more of these characteristics by simultaneously pushing the user interface  264  and the trigger  218  for a predetermined period of time. 
     Once in the programming mode, the status indicator  266  could indicate the particular characteristic selected to be changed. By way of example only, the status indicator  266  could indicate the selected characteristics as follows: (1) solid red—dwell; (2) solid green—debounce; (3) flashing green—rate-of-fire; and (4) alternating red/green—default firing mode. In some embodiments, the user could cycle between these characteristics using the trigger  218 . In this example, the status indicator would cycle from solid red (dwell) to solid green (debounce) when the trigger  218  is pulled and then from solid green (debounce) to flashing green (rate-of-fire) when the trigger  218  is pulled again and then from flashing green (rate-of-fire) to alternating red/green (default firing mode) if the trigger  218  is pulled again. To select a particular characteristic to change, the user could pull and hold the trigger for a predetermined time, for example. When this is done, the status indicator  266  could flash the current value selected for the characteristic. If the user selected debounce, for example, the status indicator  266  could flash 30 times if the debounce value had been set to 30 milliseconds. 
     To enter a different value, the user could pull the trigger the number of times needed to select the desired value. Consider an example in which the user selected the dwell characteristic to change. In this example, the default dwell value could be 8 milliseconds and may be adjusted between 2-20 milliseconds. If the user wanted to change the dwell value to 10 milliseconds, the user would pull the trigger 10 times. Once the user has entered the desired value, the status indicator  266  could flash (or otherwise indicate) that the value is accepted and stored. 
     Consider another example in which the user selected the debounce value to change. In this example, the default debounce value could be 52 milliseconds and may be adjusted between 25-65 milliseconds. If the user wanted to change the debounce value to 25 milliseconds, for example, the user would pull the trigger 25 times. Once the user has entered the desired value, the status indicator  266  could flash (or otherwise indicate) that the value is accepted and stored. 
     Consider a further example in which the user selected the rate-of-fire value to change. In this example, the default rate-of-fire value could be 13 balls per second and may be adjusted between 8-30 balls per second. If the user wanted to change the rate-of-fire value to 20 balls per second, for example, the user would pull the trigger 20 times. Once the user has entered the desired value, the status indicator  266  could flash (or otherwise indicate) that the value is accepted and stored. 
     Consider another example in which the user selected the firing mode value to change. In this example, the firing mode value could be 2, which could correspond to safe full-auto. If the user wanted to change the firing mode to auto-response, which corresponds to a firing mode value of 3 in this example, the user would pull the trigger 3 times. Once the user has entered the desired value, the status indicator  266  could flash (or otherwise indicate) that the value is accepted and stored. 
     Although the present disclosure has been described with reference to particular means, materials and embodiments, from the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the invention and various changes and modifications may be made to adapt the various uses and characteristics without departing from the spirit and scope of the invention.