Patent Publication Number: US-10760860-B2

Title: Firearm systems and methods for accommodating different bullet casing lengths

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application is a continuation of U.S. patent application Ser. No. 16/132,035, filed Sep. 14, 2018, which claims the benefit of U.S. Provisional Patent Application No. 62/567,711, filed Oct. 3, 2017, both of which are incorporated herein by reference in their entireties. 
    
    
     BACKGROUND 
     Firearms have long required the use of bullets having casings of specific dimensions. For example, a firearm chambered to fire 9 mm cartridges has traditionally required the use of 9 mm cartridges. Cartridges having bullets of the same diameter and the same style casings but with different casing lengths could not be interchangeably fired from the same firearm. 
     SUMMARY 
     The embodiments of this invention allow for ammunition having the same projectile diameter but different casing lengths to be fired interchangeably from a single firearm. The various embodiments are directed at different operational methods of different firearms. 
     One embodiment relates to a firearm that includes a frame assembly, a slide assembly releasably and slidably coupled to the frame assembly, a bolt assembly including a leading surface, a firing pin, and an adjuster. The adjuster includes a body and an extension. The body defines a first bore, defines a leading surface, and has a thickness. The leading surface is configured to interface with a rear portion of a cartridge, and the body spaces the leading surface from the leading surface of the bolt assembly. The extension couples the body to the bolt assembly and defines a second bore that shares a common central axis with the first bore. The first bore and the second bore receive the firing pin such that the firing pin at least selectively protrudes from the leading surface of the adjuster to engage the cartridge. 
     Another embodiment relates to an adjuster that includes a body and an extension. The body defines a first bore, defines a leading surface, and has a thickness. The leading surface is configured to interface with a rear portion of a cartridge, and the body is configured to space the leading surface from a leading surface of a bolt assembly. The extension is configured to couple the body to the bolt assembly and defines a second bore that shares a common central axis with the first bore. The first bore and the second bore are configured to receive a firing pin and thereby facilitate at least selective protrusion of the firing pin from the leading surface of the adjuster and engagement of the firing pin with the cartridge. 
     Yet another embodiment relates to a method of accommodating firing different lengths of cartridges with a single firearm. The method includes providing a firearm configured to fire a first cartridge of a first length and providing an adjuster to accommodate firing a second cartridge of a second length. Providing the adjuster includes coupling the adjuster to a bolt assembly of the firearm. 
     The invention is capable of other embodiments and of being carried out in various ways. Alternative exemplary embodiments relate to other features and combinations of features as may be recited herein. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The disclosure will become more fully understood from the following detailed description, taken in conjunction with the accompanying figures, wherein like reference numerals refer to like elements, in which: 
         FIG. 1  is a side view of a recoil operated firearm having an adjuster assembly, according to an exemplary embodiment; 
         FIG. 2  is a rear perspective view of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 3  is a perspective view of the adjuster assembly of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 4  is a perspective view of a firing assembly of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 5  is a perspective view of the adjuster assembly and a bolt assembly of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 6  is a perspective view of an adjuster knob of the adjuster assembly of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 7  is another perspective view of an adjuster knob of the adjuster assembly of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 8  is a side partially-exploded view of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 9  is a perspective view of an adjuster of the adjuster assembly of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 10  is a perspective view of a slide of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIGS. 11-15  are rear perspective views of the firearm of  FIG. 1  with the adjuster knob and slide thereof in various orientations, according to an exemplary embodiment; 
         FIGS. 16 and 17  are perspective views of the slide of the firearm of  FIG. 1  with the bolt assembly thereof in various orientations, according to an exemplary embodiment; 
         FIGS. 18 and 19  are perspective views of the firearm of  FIG. 1  with the bolt assembly thereof in various orientations, according to an exemplary embodiment; 
         FIG. 20  is a perspective view of two shell casings that the firearm of  FIG. 1  is configured to interchangeably fire, according to an exemplary embodiment; 
         FIGS. 21 and 22  are perspective views of two shell casings positioned within a chamber of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIGS. 23 and 24  are perspective views of an ejector of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 25  is a perspective view of the slide of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 26  is another perspective view of an extractor of the firearm of  FIG. 1 , according to an exemplary embodiment; 
         FIG. 27  is a side view of a blow back and/or gas delayed blow back operated firearm having an adjuster assembly, according to another exemplary embodiment; 
         FIG. 28  is a side view of an ejector of the firearm of  FIG. 27 , according to an exemplary embodiment; 
         FIG. 29  is a side view of a slide of the firearm of  FIG. 27 , according to an exemplary embodiment; and 
         FIG. 30  is a perspective view of an adjuster assembly of the firearm of  FIG. 27 , according to an exemplary embodiment. 
     
    
    
     DETAILED DESCRIPTION 
     Before turning to the figures, which illustrate the exemplary embodiments in detail, it should be understood that the present application is not limited to the details or methodology set forth in the description or illustrated in the figures. It should also be understood that the terminology is for the purpose of description only and should not be regarded as limiting. 
     According to an exemplary embodiment, a firearm includes an adjuster assembly configured to facilitate interchangeably firing cartridges having bullets of the same diameter and the same style casings but with different casing lengths. In other words, the adjuster assembly is configured to facilitate firing rounds having different casing lengths from the same firearm. In one embodiment, the firearm is a pistol. The pistol may be recoil operated, blow back operated and/or gas delayed blow back operated. Regardless of the pistol operation, the adjuster assembly is configured to selectively reposition a rear (e.g., relative to the end of the barrel from which the bullet is expelled, relative to the muzzle of the firearm, etc.) portion (e.g., a rear face, a rear edge, etc.) of the bullet relative to the barrel. The adjuster assembly thereby facilitates providing similar head space regardless of the length of the casing. In one embodiment, the firearm including the adjuster assembly provides increased flexibility to the operator in that cartridges having different casing lengths may be interchangeably fired. In another embodiment, the firearm including the adjuster assembly additionally or alternatively reduces the cost of ownership in that the operator may use certain, less expensive cartridges for training and/or target practice and then use other, more expensive cartridges for live fire exercises. 
     According to the exemplary embodiment shown in  FIGS. 1 and 2 , a firearm, shown as pistol  100 , includes a frame assembly, shown as frame assembly  200 , a slide assembly, shown as slide assembly  300 , and a barrel, shown as barrel  400 . As shown in  FIGS. 1 and 2 , pistol  100  is recoil operated. Slide assembly  300  is releasably and slidably coupled to frame assembly  200 . As shown in  FIGS. 1 and 2 , pistol  100  also includes a hammer, shown as hammer  500 , a trigger assembly, shown as trigger assembly  600 , a safety, shown as safety  700 , a grip, shown as grip  800 , and a firing assembly, shown as firing assembly  900 . Pistol  100  may alternatively include more or fewer components (e.g., pistol  100  may not include grip  800 , etc.). As shown in  FIG. 2 , pistol  100  includes a plurality of fasteners, shown as pins  210 . Pins  210  may couple various other components of pistol  100  to frame assembly  200 . By way of example, pins  210  may couple trigger assembly  600  to frame assembly  200 . According to the exemplary embodiment shown in  FIGS. 1 and 2 , pistol  100  includes an adjuster assembly, shown as adjuster assembly  1000 . In one embodiment, adjuster assembly  1000  is configured to selectively reposition a rear portion of a cartridge relative to barrel  400  thereby providing increased flexibility to the operator in that cartridges having different casing lengths may be interchangeably fired from pistol  100 . 
     According to the exemplary embodiment shown in  FIG. 3 , adjuster assembly  1000  includes an actuator, shown as knob  1100 , and an adjuster, shown as adjuster  1200 . An operator may engage knob  1100  to selectively reconfigure pistol  100  into various orientations (e.g., between two orientations, etc.) and thereby facilitate interchangeably firing cartridges having different casing lengths. Knob  1100  engages adjuster  1200 , according to an exemplary embodiment. As shown in  FIG. 3 , knob  1100  includes a body, shown as body  1110 , and an extension, shown as extension  1120 , that protrudes therefrom. Adjuster  1200  is elongated and has a first end  1210  and a second end  1220 . As shown in  FIG. 3 , adjuster  1200  includes an interface, shown as interface  1230 , at first end  1210  and a coupler, shown as coupler  1240 , at second end  1220 . Extension  1120  of knob  1100  and interface  1230  of adjuster  1200  have mating shapes, according to an exemplary embodiment. A portion of adjuster  1200  has a circular cross-sectional shape, according to an exemplary embodiment. In other embodiments, adjuster  1200  has another cross-sectional shape (e.g., square, etc.). Interface  1230  has the cross-sectional shape (e.g., in a plane to which a longitudinal axis of adjuster  1200  is orthogonal, etc.) of a circle sector (e.g., a half-disk, etc.), according to an exemplary embodiment. Extension  1120  also has the cross-sectional shape (e.g., in a plane parallel to a surface of body  1110 , in a plane to which a longitudinal axis of adjuster  1200  is orthogonal, etc.) of a circle sector (e.g., a half-disk, etc.), according to an exemplary embodiment. An operator may manipulate knob  1100  to selectively reorient adjuster  1200 . By way of example, an operator may rotate knob  1100 , and engagement between extension  1120  and interface  1230  may rotate adjuster  1200 . 
     As shown in  FIG. 4 , firing assembly  900  includes a firing pin, shown as firing pin  910 , and a resilient member, shown as spring  920 . In one embodiment, knob  1100  receives firing pin  910 . By way of example, firing pin  910  may protrude from a surface of knob  1100 . Hammer  500  of pistol  100  is configured to strike a first end  912  of firing pin  910 , thereby driving a second end  914  of firing pin  910  into a primer of the cartridge to fire the round. In one embodiment, firing pin  910  includes a first interface, shown as shoulder  916 , and a second interface, shown as shoulder  918 . Spring  920  is configured to interface with shoulder  918  and bias shoulder  916  into engagement with a surface of knob  1100 , according to an exemplary embodiment. 
     As shown in  FIG. 5 , adjuster assembly  1000  interfaces with a bolt assembly, shown as bolt assembly  1300 . Bolt assembly  1300  and adjuster assembly  1000  (e.g., adjuster  1200 , etc.) receives firing assembly  900 , according to an exemplary embodiment. As shown in  FIG. 5 , firing pin  910  protrudes from bolt assembly  1300  (e.g., when hammer  500  engages with an opposing end thereof, etc.). Coupler  1240  of adjuster  1200  engages an interface, shown as interface  1310 , of bolt assembly  1300 , according to an exemplary embodiment. In one embodiment, interface  1310  is defined by a bolt of bolt assembly  1300 . As shown in  FIG. 5 , coupler  1240  of adjuster  1200  includes a first portion  1242  and a second portion  1244  that cooperate with other portions of adjuster  1200  to define a recess  1246 . Recess  1246  receives a catch, shown as catch  1312 , of interface  1310  of bolt assembly  1300 , according to an exemplary embodiment. Engagement of catch  1312  with first portion  1242  couples bolt assembly  1300  to adjustment assembly  1000  while facilitating relative motion therebetween, according to an exemplary embodiment. By way of example, adjuster  1200  may be rotated (e.g., through rotation of knob  1100  by an operator, etc.), and adjuster  1200  may remain coupled to bolt assembly  1300  without causing rotation thereof (e.g., first portion  1242  and second portion  1244  of adjuster  1200  may rotate with interface  1310  of bolt assembly  1300 , etc.). As shown in  FIG. 5 , first portion  1242  and second portion  1244  have a circular cross-sectional shape (e.g., within a plane to which a longitudinal axis of adjuster  1200  is orthogonal, etc.), and catch  1312  similarly has a circular cross-sectional shape (e.g., within a plane to which a longitudinal axis of bolt assembly  1300  is orthogonal, etc.). In other embodiments, first portion  1242 , second portion  1244 , and/or catch  1312  have a different cross-sectional shape. 
     According to the exemplary embodiment shown in  FIG. 5 , bolt assembly  1300  includes an extractor, shown as extractor  1320 . Extractor  1320  interfaces with a casing of a cartridge (e.g., a rim at the base thereof, etc.) to pull the casing rearward, according to an exemplary embodiment. In other embodiments, bolt assembly  1300  does not include extractor  1320  and instead includes other components configured to reposition the casing. 
     As shown in  FIG. 5 , bolt assembly  1300  defines a recess, shown as slot  1330 . In one embodiment, slot  1330  is defined by the bolt of bolt assembly  1300 . Slot  1330  is positioned across an upper portion of bolt assembly  1300 , according to an exemplary embodiment. As shown in  FIG. 5 , slot  1330  is defined by a leading edge  1332 , a trailing edge  1334 , and an adjoining surface  1336 . A length of slot  1330  extends between leading edge  1332  and trailing edge  1334 , and a width of slot  1330  extends perpendicular to the length thereof. Bolt assembly also defines a notch, shown as notch  1338 , that accommodates and/or receives the end of barrel  400  in one or more positions of bolt assembly  1300  (e.g., when bolt assembly  1300  is disposed in a forward position, etc.). 
     As shown in  FIG. 6 , body  1110  of knob  1100  defines a recess, shown as recess  1130 . Recess  1130  is configured to selectively receive hammer  500  of pistol  100 , according to an exemplary embodiment. In one embodiment, knob  1100  defines an aperture, shown as bore  1140 , that is configured to receive firing pin  910  of firing assembly  900 . Firing pin  910  may protrude from a first surface  1112  of body  1110  in an extended position and be driven from the extended position by hammer  500  (e.g., as hammer  500  strikes firing pin  910 , etc.). In one embodiment, the portion of body  1110  that defines first surface  1112  serves as a retainer plate that holds firing pin  910  in place. 
     Recess  1130  has the shape of an arched doorway, according to an exemplary embodiment. As shown in  FIG. 6 , recess  1130  extends to and through a lower end of body  1110  and is spaced from an upper end of body  1110  such that a rim, shown as rim  1114 , is formed along an upper portion of body  1110 . Recess  1130  is laterally defined by a first wing and a second wing, shown in  FIG. 6  as first wing  1106  and second wing  1108 . Recess  1130  receives hammer  500  of pistol in certain orientations. By way of example, hammer  500  may extend through the open lower end of body  1110  (e.g., the portion thereof that defines recess  1130 , etc.) and strike firing pin  910  to fire the cartridge. Rim  1114 , first wing  1106 , and second wing  1108  may prevent hammer  500  from entering recess  1130  and striking firing pin  910  in certain orientations of knob  1100  (e.g., when knob  1100  is upside down, when knob  1100  is rotated 180 degrees from the orientation shown in  FIG. 6  about an axis along which extension  1120  protrudes, etc.). 
     As shown in  FIG. 7 , body  1110  of knob  1100  is defined by a second surface  1116 . A detent, shown as detent  1118 , is formed in second surface  1116 , according to the exemplary embodiment shown in  FIG. 7 . Detent  1118  may cooperate with a retainer of slide assembly  300  to hold knob  1100  in position. 
     According to the exemplary embodiment shown in  FIG. 7 , extension  1120  defines a recess, shown as groove  1122 . Groove  1122  extends inward, toward a longitudinal centerline of extension  1120  from an outer surface thereof, according to an exemplary embodiment. As shown in  FIG. 7 , groove  1122  is defined between a leading edge  1124  and a trailing edge  1126  of extension  1120 . In other embodiments, groove  1122  is otherwise defined (e.g., between leading edge  1124  and second surface  1116  of body  1110 , etc.). 
     As shown in  FIG. 8 , slide assembly  300  defines apertures  310 . In one embodiment, apertures  310  are configured (e.g., sized, etc.) to receive a first pin  212  and a second pin  214 . First pin  212  and second pin  214  may be the same or different sizes (e.g., diameters, etc.), according to various embodiments. In one embodiment, knob  1100  is coupled to slide assembly  300  with first pin  212 , and bolt assembly  1300  is coupled to slide assembly  300  with second pin  214 . By way of example, groove  1122  of extension  1120  of knob  1100  may receive first pin  212 . Engagement between first pin  212  and extension  1120  may limit translational movement between knob  1100  and slide assembly  300 . Groove  1122  may extend circumferentially around extension  1120  such that knob  1100  is freely rotatable (e.g., 360 degrees, etc.) about a central axis thereof relative to slide assembly  300 . First pin  212  may thereby hold knob  1100  within slide assembly  300 . By way of another example, slot  1330  of bolt assembly  1300  may receive second pin  214 . Engagement between second pin  214  and the bolt of bolt assembly  1300  (e.g., contact between second pin  214  and adjoining surface  1336 , etc.) may limit rotational movement between bolt assembly  1300  and slide assembly  300 . The length of slot  1330  facilitates limited translational movement between bolt assembly  1300  and slide assembly  300 . By way of example, second pin  214  may contact trailing edge  1334  of bolt assembly  1300  when bolt assembly  1300  is in a first position (e.g., an extended position, etc.), and second pin  214  may contact leading edge  1332  of bolt assembly  1300  when bolt assembly  1300  is in a second position (e.g., a withdrawn position, a retracted position, etc.). 
     As shown in  FIG. 9 , adjuster  1200  includes a plurality of threads  1250 . The plurality of threads  1250  may be acme square threads or another type of thread, according to various embodiments. According to the embodiment shown in  FIG. 9 , the plurality of threads  1250  are defined within a surface of adjuster  1200  and disposed between (e.g., longitudinally between, etc.) interface  1230  and coupler  1240 . 
     As shown in  FIG. 10 , slide assembly  300  includes a bore, shown as bore  320  defined along a length thereof. Slide assembly  300  includes a plurality of threads  330  within bore  320 . In one embodiment, the plurality of threads  330  within bore  320  correspond with the plurality of threads  1250  of adjuster  1200 . Slide assembly  300  may thereby receive adjuster  1200  within bore  320 . Adjuster  1200  may be threaded into bore  320  (e.g., by engagement of the plurality of threads  1250  of adjuster  1200  with the plurality of threads  330  within bore  320 , etc.). As adjuster  1200  is rotated relative to slide assembly  300 , adjuster  1200  is fed into or withdrawn from bore  320  (i.e., rotational movement of adjuster  1200  produces longitudinal movement thereof, etc.). In one embodiment, rotation of adjuster  1200  thereby selectively repositions bolt assembly  1300  between the first position and the second position due to engagement between coupler  1240  and interface  1310 . According to an exemplary embodiment, bolt assembly  1300  (e.g., a body thereof, etc.) has a diameter that is larger than the outer diameter of adjuster  1100  and/or the inner diameter of slide assembly  300 . Bolt assembly  1300  may thereby be sized to prevent inadvertent discharge of bolt assembly  1300  out the back of slide assembly  300 . 
     As shown in  FIG. 10 , slide assembly  300  includes a retainer, shown as retainer  340 . Retainer  340  is a ball configured to engage with detent  1118  to selectively hold knob  1100  in a desired position, according to an exemplary embodiment. A resilient member (e.g., a spring, etc.) may bias retainer  340  outward, away from slide assembly  300 . 
     As shown in  FIGS. 11-19 , knob  1100  is rotatable relative to slide assembly  300 . As shown in  FIGS. 11 and 12 , slide assembly is oriented in a battery position. Knob  1100  is shaped and/or otherwise configured to interfere with hammer  500  to prevent substantial rotation of hammer  500  relative to slide assembly  300 . Such interference may reduce the risk of inadvertent repositioning of bolt assembly  1300  with pistol  100  loaded. As shown in  FIGS. 13 and 14 , knob  1100  is freely rotatable with slide assembly  300  positioned in a locked-back or otherwise withdrawn orientation. Knob  1100  may be rotatable counter-clockwise from an initial position, shown in  FIG. 13 , to an intermediate position, shown in  FIG. 14 , and ultimately back to the initial position. As shown in  FIG. 15 , rim  1114  of knob  1100  interferes with hammer  500  if slide assembly  300  is released from the locked-back or otherwise withdrawn orientation and knob  1100  is disposed in any position other than the initial position or another orientation 360 degrees offset therefrom. With slide assembly  300  released from the locked-back or otherwise withdrawn orientation and knob  1100  not in the initial position or another orientation 360 degrees offset therefrom, rim  1114  and/or another portion of knob  1100  is disposed between firing pin  910  and hammer  500 . Knob  1100  may thereby prevent inadvertent engagement of firing pin  910  (i.e., inadvertent firing of pistol  100 , etc.) by permitting contact between hammer  500  and firing pin  910  only when knob  1100  is in one of two prescribed position (e.g., the first position or the second position, etc.). 
     Knob  1100  may thereby be rotatable 360 degrees in either direction (e.g., clockwise, counter-clockwise, etc.). Engagement between second pin  214  and trailing edge  1334  and leading edge  1332  of bolt assembly  1300  may limit further rotation of adjuster  1100 . By way of example, in the orientation shown in  FIG. 13 , bolt assembly  1300  may be in the first position with second pin  214  contacting trailing edge  1334  of bolt assembly  1300 . Rotation clockwise from the initial positions shown in  FIG. 13  may be limited (e.g., prevented, etc.) due to engagement of second pin  214  with trailing edge  1334  of bolt assembly  1300 . Rotation counter-clockwise from the initial position shown in  FIG. 13  may occur as adjuster  1200  draws bolt assembly  1300  back and second pin  214  slides across adjoining surface  1336  until second pin  214  contacts leading edge  1332  of bolt assembly  1300 . Further counter-clockwise rotation may be limited (e.g., prevented, etc.) due to engagement of second pin  214  with leading edge  1332  of bolt assembly  1300 . Knob  1100  may thereby turn adjuster  1200  to reconfigure bolt assembly  1300  between the first position, shown in  FIGS. 16 and 18 , and the second position, shown in  FIGS. 17 and 19 . 
     As shown in  FIGS. 20-22 , adjuster assembly  1000  facilitates firing cartridges having bullets of the same diameter and the same style casings but with different casing lengths. Pistol  100  may interchangeably fire a first casing, shown as first casing  1400 , and a second casing, shown as second casing  1500 . As shown in  FIG. 20 , first casing  1400  is a distance X longer than second casing  1500 . In one embodiment, first casing  1400  is a .45 ACP casing, and second casing  1500  is a .45 GAP casing. As shown in  FIG. 21 , first casing  1400  is disposed within the bore of barrel  400 . As shown in  FIG. 22 , second casing  1500  is disposed within the bore of barrel  400 . Second casing  1500  is shorter than first casing  1400  and is thereby recessed into the end of barrel  400  relative to the position of first casing  1400 . In one embodiment, adjuster assembly  1000  repositions bolt assembly  1300  to accommodate first casing  1400  when bolt assembly  1300  is in the second position and accommodate second casing  1500  when bolt assembly  1300  is in the first position. 
     As shown in  FIGS. 23 and 24 , pistol  100  is particularly configured to eject casings. According to an exemplary embodiment, pistol  100  includes an ejector, shown as ejector  1600 . Ejector  1600  is pivotally coupled to frame assembly  200  of pistol  100 , according to an exemplary embodiment. As shown in  FIG. 23 , ejector  1600  includes a leading point, shown as leading point  1610 , a leading surface, shown as leading surface  1620 , a depression, shown as depression  1630 , and a trailing surface, shown as trailing surface  1640 . Leading point  1610  contacts the casing to eject the casing as slide assembly  300  moves backward after firing. As shown in  FIGS. 23 and 24 , ejector  1600  is disposed in a level orientation (e.g., flat, horizontal, not rocked forward, not rocked backward, etc.) when slide assembly  300  is in battery (e.g., with pistol  100  loaded, with pistol  100  unloaded, etc.). 
     Slide assembly  300  includes a plurality of ramps and recesses that accommodate and actuate ejector  1600 . As shown in  FIG. 25 , slide assembly  300  includes a leading ramp, shown as leading ramp  350 , a mound, shown as mound  360 , a trailing ramp, shown as trailing ramp  370 , and a depression, shown as depression  380 . In one embodiment, leading surface  1620  of ejector  1600  is disposed along leading ramp  350 , depression  1630  of ejector  1600  receives mound  360 , and trailing surface  1640  of ejector  1600  is disposed along trailing ramp  370  when slide assembly  300  is in battery. As slide assembly  300  moves rearward, trailing ramp  370  of slide assembly  300  engages trailing surface  1640  of ejector  1600 . Trailing ramp  370  and trailing surface  1640  are shaped (e.g., curved, ramped, etc.) such that further rearward motion of slide assembly  300  toggles ejector  1600  (e.g., clockwise when viewed as shown in  FIG. 23 , etc.) and brings leading point  1610  upward into the position shown in  FIG. 26 . Contact between the casing and leading point  1610  ejects the casing from the chamber of pistol  100 . As slide thereafter moves forward, leading ramp  350  of slide assembly  300  engages leading surface  1620  of ejector  1600 . Leading ramp  350  and leading surface  1620  are shaped (e.g., curved, ramped, etc.) such that further forward motion of the slide toggles ejector  1600  (e.g., counter-clockwise when viewed as shown in  FIG. 23 , etc.) and brings leading point  1610  downward. Ejector  1600  and pistol  100  having slide assembly  300  that toggles ejector  1600  facilitates providing enhanced structural material around bore  320  of slide assembly  300 . As shown in  FIGS. 10 and 25 , slide assembly  300  includes a slot, shown as slot  390 , that receives ejector  1600 . Pistol  100  having an articulating ejector  1600  facilitates providing an increased thickness t between the wall of bore  320  and the slot  390 . 
     According to the exemplary embodiment shown in  FIG. 27 , a blowback and/or gas delay blowback firearm, shown as pistol  2000 , includes a frame assembly, shown as frame assembly  2100 , a slide assembly, shown as slide assembly  2200 , and a barrel, shown as barrel  2300 . Slide assembly  2200  is releasably and slidably coupled to frame assembly  2100 . Slide assembly  2200  defines an aperture  2210  that exposes a chamber of pistol  2000 . In one embodiment, aperture  2210  extends further forward (e.g., further toward the muzzle of barrel  2300 , etc.) relative to corresponding apertures of similar blowback operated firearms. As shown in  FIGS. 27 and 28 , pistol  2000  also includes a trigger assembly, shown as trigger assembly  2400 , and an extractor, shown as extractor  2500 . Pistol  2000  may alternatively include more or fewer components. 
     According to the exemplary embodiment shown in  FIG. 30 , pistol  2000  includes an adjuster assembly, shown as adjuster assembly  2600 . In one embodiment, adjuster assembly  2600  is configured to selectively reposition a rear portion of a cartridge relative to barrel  2300  thereby providing increased flexibility to the operator in that cartridges having different casing lengths may be interchangeably fired from pistol  2000 . As shown in  FIG. 30 , adjuster assembly  2600  includes an adjuster having a body, shown as body  2610 , and an extension, shown as extension  2620 . In other embodiments, the adjuster does not include extension  2620 . According to the exemplary embodiment shown in  FIG. 30 , extension  2620  couples body  2610  to a bolt assembly, shown as bolt assembly  2700 , of pistol  2000 . Body  2610  and extension  2620  include an aperture, shown as aperture  2630 , that receives a firing pin, shown as firing pin  2800 , of pistol  2000 . Firing pin  2800  engages a primer of a cartridge as pistol  2000  is fired. Adjuster assembly  2600  spaces the rear portion of a cartridge from a surface  2710  of bolt assembly  2700 . In traditional firearms, the cartridge would interface with (e.g., contact, etc.) surface  2710  of bolt assembly  2700 . Body  2610  of adjuster assembly  2600  may have a thickness that corresponds with (e.g., is equal to, etc.) the difference in length between the two casings pistol  2000  is configured to interchangeably fire. By way of example, pistol  2000  may have head spacing equal to the distance between the surface the rear of the casing engages and barrel  2300 . Pistol  2000  without adjuster assembly  2600  may have head spacing equal to the distance between surface  2710  and barrel  2300 . Pistol  2000  with adjuster assembly  2600  may have head spacing equal to the distance between a leading surface  2612  of body  2610  and barrel  2300 . Pistol  2000  without adjuster assembly  2600  may have head spacing selected to correspond with the length of a 9 mm caliber casing. A .380 caliber casing has a smaller diameter and a shorter length than a 9 mm caliber casing. Adjuster assembly  2600  may provide head spacing to accommodate the .380 caliber casing. By way of example, body  2610  may have a thickness equal to the difference in length between a .380 caliber casing and a 9 mm caliber casing. In one embodiment, aperture  2210  of slide assembly  2200  extends further forward (e.g., further toward the muzzle of barrel  2300 , etc.) relative to corresponding apertures of similar blowback operated firearms (e.g., a distance equal to the thickness of a portion of body  2610 , etc.). 
     The front edges of both casings may sit at the same front position, but the back edges thereof may be at different positions (e.g., due to the difference in casing lengths. Extractor  2500  may be longer than ejectors of traditional pistols (e.g., longer than a 9 mm extractor, etc.). Extractor  2500  thereby accommodates removing shorter casings from a chamber of pistol  2000 . 
     In another embodiment, pistol  2000  without adjuster assembly  2600  may have head spacing selected to correspond with the length of a 10 mm caliber casing, and adjuster assembly  2600  may provide head spacing to accommodate a .40 caliber casing. Slide assembly  2200  may be oriented in a full battery position when the shorter shell option is chambered and may be oriented in a second position (e.g., slightly rearward relative to the full battery position, etc.) when the longer shell option is chambered. 
     Slide assembly  2200  facilitates firing pistol  2000  even with slide assembly  2200  oriented in the second position (e.g., slide assembly  2200  may be designed such that the safety of pistol  2000  does not prevent firing even if slide assembly  2200  is not in full battery, etc.). By way of example, slide assembly  2200  may include one or more apertures (e.g., grooves, etc.) where slides of traditional pistols would include material that engages with a safety mechanism to prevent firing. By way of another example, slide assembly  2200  may include a projection where slides of traditional pistols would not include material. 
     As utilized herein, the terms “approximately”, “about”, “substantially”, and similar terms are intended to have a broad meaning in harmony with the common and accepted usage by those of ordinary skill in the art to which the subject matter of this disclosure pertains. It should be understood by those of skill in the art who review this disclosure that these terms are intended to allow a description of certain features described and claimed without restricting the scope of these features to the precise numerical ranges provided. Accordingly, these terms should be interpreted as indicating that insubstantial or inconsequential modifications or alterations of the subject matter described and claimed are considered to be within the scope of the invention as recited in the appended claims. 
     It should be noted that the terms “exemplary” and “example” as used herein to describe various embodiments is intended to indicate that such embodiments are possible examples, representations, and/or illustrations of possible embodiments (and such term is not intended to connote that such embodiments are necessarily extraordinary or superlative examples). 
     The terms “coupled,” “connected,” and the like, as used herein, mean the joining of two members directly or indirectly to one another. Such joining may be stationary (e.g., permanent, etc.) or moveable (e.g., removable, releasable, etc.). Such joining may be achieved with the two members or the two members and any additional intermediate members being integrally formed as a single unitary body with one another or with the two members or the two members and any additional intermediate members being attached to one another. 
     References herein to the positions of elements (e.g., “top,” “bottom,” “above,” “below,” “between,” etc.) are merely used to describe the orientation of various elements in the figures. It should be noted that the orientation of various elements may differ according to other exemplary embodiments, and that such variations are intended to be encompassed by the present disclosure. 
     Also, the term “or” is used in its inclusive sense (and not in its exclusive sense) so that when used, for example, to connect a list of elements, the term “or” means one, some, or all of the elements in the list. Conjunctive language such as the phrase “at least one of X, Y, and Z,” unless specifically stated otherwise, is otherwise understood with the context as used in general to convey that an item, term, etc. may be either X, Y, Z, X and Y, X and Z, Y and Z, or X, Y, and Z (i.e., any combination of X, Y, and Z). Thus, such conjunctive language is not generally intended to imply that certain embodiments require at least one of X, at least one of Y, and at least one of Z to each be present, unless otherwise indicated. 
     It is important to note that the construction and arrangement of the systems as shown in the exemplary embodiments is illustrative only. Although only a few embodiments of the present disclosure have been described in detail, those skilled in the art who review this disclosure will readily appreciate that many modifications are possible (e.g., variations in sizes, dimensions, structures, shapes and proportions of the various elements, values of parameters, mounting arrangements, use of materials, colors, orientations, etc.) without materially departing from the novel teachings and advantages of the subject matter recited. For example, elements shown as integrally formed may be constructed of multiple parts or elements. It should be noted that the elements and/or assemblies of the components described herein may be constructed from any of a wide variety of materials that provide sufficient strength or durability, in any of a wide variety of colors, textures, and combinations. Accordingly, all such modifications are intended to be included within the scope of the present inventions. Other substitutions, modifications, changes, and omissions may be made in the design, operating conditions, and arrangement of the preferred and other exemplary embodiments without departing from scope of the present disclosure or from the spirit of the appended claims.