US3537352A

US3537352A - Air ignition gun

Info

Publication number: US3537352A
Application number: US754133*A
Authority: US
Inventors: Ronald Wayne Joyce
Original assignee: Victor Comptometer Corp
Current assignee: Kidde Inc
Priority date: 1968-07-25
Filing date: 1968-07-25
Publication date: 1970-11-03
Anticipated expiration: 1987-11-03

Description

Inventor Ronald Wayne Joyce [56] References Cited $11ringdale,Arkansas UNITED STATES PATENTS Q A- 1968 2,480,100 8/1949 Weiss et al 89/26X e d g Y 3 11970 3,008,258 11 1961 Johnson 42 14 9 1 3,114,290 12/1963 Harvey et al 89/26 Assgnee 3 302 319 2/1967 ROSSelet 89/7X chug, P 3,354,780 11/1967 Ramsay 89/26 a corporation of Illinois Primary ExaminerSamuel W. Engle Attorney-Harness, Dickey & Pierce AIR IGNITION GUN 2 Claims, 8 Drawing Figs.

U.S. Cl 89/7,

' 89/26, 124/ l 5 ABSTRACT: There is herein disclosed a firearm having an air Int. Cl F41! 1/04 ignition system for igniting a solid propellant by surface con- Field of Search 124/] l, 13, tact with high temperature compressed air and provided with 14, 15; 89/1, 26, 27, 7; 42/l5-22 a new and improved air compression cylinder assembly.

Patentd Nov. 3, 1970 3,537,352

INVENTOR.

/70/71 fig:

. Patented No 3,1970 3,537,352

Sheet 4 of 4 ZFMAM/A/ lym AIR IGNITION GUN PRIOR ART This invention relates to improvements in firearms having an ignition system of the type disclosed in copending U.S. Pat. applications Ser. No. 469,992 filed July 7, 1965; Ser. No. 473.556 filed July 7, I965; Ser. No. 598,086 filed Nov. 30. I966, now U.S. Pat. No. 3,503,299 Ser. No. 598,087 filed Nov. 30, 1966, now US. Pat. Ser. No. 3,399,596; Ser. No. 683,029 filed Nov. l4, I967; and issued U.S. Pat. No. 3,302,523. The disclosures of the above-identified applications and patent are specifically incorporated herein by reference.

SUMMARY OF INVENTION The inventive concepts herein disclosed relate to:

1. An air compression cylinder assembly having an obturation-air passage-valve plug member of new and improved design attached to a compression cylinder in a new and improved manner;

2. Obturation means between relatively movable ammunition holding means and air compression cylinder means of new and improved design;

3. A trigger-sear assembly of new and improved design;

4. A receiver assembly of new and improved design;

5. A cocking assembly of new and improved design; and

6. A safety assembly of new and improved design.

DRAWINGS An illustrative embodiment of the various inventive concepts is shown in the accompanying drawings in which:

FIG. I is a side elevational view of a rifle type firearm em bodying the inventive features;

FIG. 2 is an enlarged detail view of a portion of the receiver of the firearm of FIG. 1;

FIG. 3 is an enlarged partial view of the firearm of FIG. I, with parts broken away, showing the trigger-sear assembly;

FIG. 4 is an enlarged partial view of the firearm of FIG. 1 showing the cylinder head-barrel relationship in the firing position;

FIG. 5 is a partial cross-sectional view taken along the line 5-5 in FIG. 3;

FIG. 6 is a partial side elevational view of the back side of the firearm shown in FIG. I; 7

FIG. 7 is an enlarged partial view of the firearm of FIG. 1 showing the end cap-compression spring assembly; and

FIG. 8 is an end view of the receiver shown in FIG. 2.

DETAILED DESCRIPTION In General Referring now to FIG. I, there is shown a rifle type firearm adapted to fire caseless ammunition ignitable by surface contact of a solid propellant with high temperature air. The main working components of the firearm comprise a barrel assembly I0, an air cylinder assembly 12, a piston assembly 13, a trigger-sear assembly 14, and a cocking lever assembly 16. A tubular receiver 18, FIGS. 2 and 8, is supported on and extends between a front support block 20, to which it is fixedly attached as by brazing, and a rear support block 22, FIG. 1. The barrel assembly 10 and the front receiver block 20 are mounted on a forearm portion 24 of a wooden stock 26 as by threaded

fastening elements

28, 30. The rear support block 22 is secured on the stock 26 by a threaded fastening element 32. A trigger guard 34 is alsoattached to the stock by element 32 and further supported by transverse pin means 36 which may be solid as shown in FIG. 1 or sleeved as shown in FIG. 3.

Air Cylinder Assembly The cylinder assembly I2, FIGS. 1 and 4, is reciprocably movable and comprises a tubular member 38 of cylindrical cross-sectional configuration fixedly attached to, as by brazing, and closed at one end by a cylinder head 39 of keyhole cross-sectional configuration and at the other by a relatively movable piston assembly 13 to define a variable volume air compression chamber 40 therebetween. Transverse passage means 41 connects the compressing chamber to the atmosphere. A piston cushioning ring 42 having a central air passage 43 is mounted on the rear surface of the cylinder head 39. The tubular member 38 is mounted on a seat 44 of cylindrical cross-sectional configuration against an abutment 45. A lug portion 46 of the cylinder head extends-through a slot 47 in the bottom of the tubular member 33 and carries a transverse pin 48 for attachment to the cocking assembly. A central bore 49 of varying diameter extends axially through the cylinder head 39 and increases in diameter in a forward direction from compression chamber 40 toward the rear end of the barrel assembly. The rearwardmost and smallest diameter bore portion 50 is connected to an intermediate and enlarged bore portion 52 by a conical surface 54. Another enlarged bore portion 56 is provided on the barrel side of the cylinder head.

A plug member 57 of generally cylindrical peripheral con- 7 figuration is mounted in bore portions 50, 52, 54 of the cylinder head and has central axially extending

cylindrical bore portions

58, 60, 62, 64 of varying diameter which provide an air passage from the compression chamber 40. Bore portion 58, next adjacent the air compression chamber, is of smallest diameter and provides an air inlet passage. Bore portion 60 is of conical shape and provides a valve seat. Bore portion 62 is ol'enlurged diameter to provide a valve chamber 66. Bore portlon 64 is of further enlarged diameter to provide a firing chamber 67 having a relatively thin wall 68 which surrounds the propellant portion of the ammunition in the firing position. A ball valve 69 is freely floatingly mounted in the valve chamber 66 and confined therein by a transverse pin 70. The diameter of ball valve 69 is such that the ball valve will move freely to a closed seated position, as shown in FIG. 4, held on the conical valve seat 60 under the influence of pressure forces in the firing chamber to close the passage 58 and prevent flow of propellant gases and residue to the compression chamber. The ball valve will move freely to an open position (not shown) under balanced pressure conditions and/or under the influence of pressure forces of compressed air to allow the flow of high temperature air from the compression chamber to the firing chamber. The outer surface portions 71, 72, 74 of plug 57 correspond in size and shape to the bore portions 50, 52, 54 with cylindrical surface portion 71 of smallest diameter and cylindrical surface portion 74 of largest diameter connected by a conical surface portion 72. Plug 57 is preferably bonded in place in a gas tight manner by a suitable adhesive to prevent movement of the plug relative to the cylinder and flow of propellant gases therearound. In use of the gun, maximum forces on the plug are exerted rearwardly by propellant gases against conical cylinder head surface 54. A feature of the present arrangement is that the plug 57 may be relatively easily removed in a forward direction for maintenance and repair or replacement upon disassembly of the A chamber 76 is provided between the outer surface portion 74 of the plug and the bore portion 56 in the cylinder head. The length of the obturation chamber is approximately the length of the thin wall portion of the plug which surrounds the firing chamber 67. An annular obturation rim 78 on the rear end of the barrel is adapted to be matingly received in the obturation chamber 76 in the firing position shown in FIG. 4. The diameter of chamber 76 is about .0015 inch larger than the diameter of rim 78. The length of the obturation rim is less than the length of the obturation chamber 76 so that a substantial gap separates the rear of the rim from the cylinder head and interference therebetween in the firing position is completely eliminated. Axial positioning of the cylinder relative to the barrel during assembly is determined by abutting engagement of a front surface 80 of the cylinder head 39 in the firing position with a rear surface 82 of the barrel which is inserted through bore 83 and positioned, as shown in FIG. 4, protruding rearwardly beyond the rear surface 84 of the front support block so as to provide a clearance gap 86. A hole is then drilled through housing 20 and barrel l and a pin 87 is inserted to hold the barrel in the proper position relative to the air cylinder 12. Obturation rim 78 is provided with an annular counterbore 88 having an inside diameter slightly larger than the outside diameter of the front plug surface 74, 1.0., .001 inch, and ltuving a length slightly longer than the length of the plug received therewithin to avoid interference during closing movement of the cylinder to the firing position.

An ammunition holding means is provided at the rear of the barrel bore 90 adjacent the obturation counterbore by reduced diameter bore portions 92, 94 so that a round of ammunition may be inserted through the rear of the barrel and held on bore portions 92, 94 with at least a portion of the propellant extending rearwardly within the counterbore 88 in the loading position and within the firing chamber 67 in the firing position.

Thus, when the firearm is in the closed firing position of FIG. 4, the outer annular obturation rim 78 surrounds the firing chamber 67 and extends rearwardly from the ammunition holding means at the rear of the barrel to a rearwardly facing transverse end surface 95. The rearwardly facing abutment surface 82 on the ammunition holding means at the rear of the barrel extends outwardly relative to the outer rim 78 and is located forwardly of the end surface 95. A first rearwardly opening annular chamber, defined by surface 92, is located within the outer rim 78 and terminates in a transverse rearwardly facing end surface 96. The inner annular obturation rim (:8 surrounds and defines part of the firing chamber while extending forward from the air compression cylinder means 12 to a transverse forward end surface 97. The forwardly opening annular obturation chamber 76, defined by outwardly spaced axially extending annular surface 56 and a rear forwardly facing surface 98,'is located outwardly circumjacent the inner rim and matingly receives the outer rim. A second rearwardly opening annular chamber, defined by surface 88, is located inwardly circumjacent the outer rim in axial alignment with the first rearwardly opening annular chamber 92 and matingly receives the inner rim. The forwardly facing transverse surface 80 on the air compression cylinder means extends outwardly from the obturation chamber 76 and is located forwardly of the transverse surface 98 in axial alignment with and adjacent the surface 82. The length of the outer rim from surface 82 to surface 95 is less than the length of obturation chamber 76 so that the surface 95 is axially spaced from surface 98 and the inner rim 68 extends within the chamber 88 with end surface 97 located adjacent end surface 96 of chamber 92. The outside diameter of the inner rim 68 is slightly less than the inside diameter of the chamber surface 88 so as to provide primary obturation therebetween and the outside diameter of the outer rim 78 is slightly less than the inside diameter of the obturation chamber 76 so as to provide secondary obturation therebetween.

Piston Assembly Referring now to FIG. 1, the piston assembly 13 comprises a grooved piston head 100 having a piston expander ring assembly 102 mounted thereon. The piston expander ring assembly comprises a self-lubricating bronze filled Teflon piston ring of rectangular cross-sectional configuration and a polyurethane O-ring type expander such that no lubrication of the piston is required and sealing is effected between the piston and cylinder during the compression stroke. Piston head 100 has a stub shaft 104 received in a bore 106 in the end of piston rod 108 and secured therein by a pin 109. The other end of rod 108 has a scar notch 110 in a reduced diameter end portion 112 which terminates in a scar abutment surface 114. A spring sleeve 116 surrounds the piston and defines a spring chamber 118. The rear end of the spring sleeve is provided with a necked down portion 120, FIG. 3, fixedly secured in a bore 121 in an abutment plate 122, as by brazing, and providing an abutment shoulder 123 for a compression spring 124 having an inside diameter slightly larger than the outside diameter of the plunger rod and mounted thereabout in spring chamber 118 between the plunger head and the shoulder 123. The outside diameter of spring 124 is slightly smaller than the inside diameter of the sleeve 116 so that each radially supports the other with the compression cylinder assembly being axially movable both with and relative to the piston assembly along the outer periphery of the fixedly held spring sleeve 116.

Receiver Assembly Referring now to FIGS. 2 and 8, the main receiver 18 is shown to comprise a one-piece sheet metal member having keyhole type cross-sectional configuration comprising a partially cylindrical tubular upper portion 126 and spaced depending

flange portions

128, 129. If desired reinforcing plates (not shown) may be fixedly attached to the sides of the flange portions. The inner surface 130 of the upper portion 126 provides a guide-bore which slidably receives and supports the cylinder assembly 12 for axial movement therewithin between the firing position of FIG. 1 and a rearwardly spaced loading position (not shown). Slot 131 between the

flanges

128, 129 receives the lug 46 and permits the cocking lever assembly to be connected thereto. A loading port 134 in the upper portion provides access to the ammunition holding means 92, 94 at the rear of the barrel when the cylinder assembly is in a rearwardly located loading position. A sight mounting plate 137 may be mounted on top of the receiver.

The front of the receiver 18 is supported at the rear of the front support block 20 on and brazed to surface 138, FIG. 4, of corresponding keyhole configuration against a rearwardly facing shoulder 140. The rear of the receiver is supported by the rear support block 22 on a surface 142, FIG. 7 of corresponding keyhole configuration against a forwardly facing shoulder 144. Rear support block 22 has an upper rear cap portion which provides an exterior surface of the firearm connecting the upper portion of the receiver to the stock. The rear support block also has a generally U-shaped cavity 146 defined by spaced downwardly depending leg portions 147, 148, FIG. 5. A sear slot 149 is formed in the rear wall of the cavity. Locating lugs 152 (one on each side of the block), FIG. 7, extend radially outwardly from surface 142 to provide support shoulders 153 and extend forwardly of shoulder 144 and surface 142 for engagement within opposite rearwardly opening

slots

154, 155 in the receiver FIG. 8. The upper surface 156 of the lugs is tapered and the front surface 157, FIG. 7, is rounded to facilitate a new and improved assembly method hereinafter described in detail. The abutment plate 122 is centrally positioned by cylindrical surface 151 which is supportingly mounted on the forward portion of rear support block as shown in FIG. 5. A pair of opposite lugs 158. 159 on the forward end of the rear support block have transverse abutment surfaces 160, 161 which supportingly engage transverse plate abutment surfaces 162, 163. Plate 122 is further supported by inwardly curved abutment surfaces 164, 165 on corresponding curved portions 166, 167 of the lugs. Plate 122 has a depending lug portion 168 located between opposite walls 169, 170 of the lugs which are thus held within opposite circumferentially

elongated slots

171, 172 in the receiver.

Slots

171, 172 are located below the longitudinal axis of the tubular portion 126 and extend into the

flange portions

128, 129. As may be seen in FIG. 5, the

outermost surfaces

174, 175 are located apart a distance slightly less than the inside diameter of the tubular portion. Opposite support lugs 176 (there being one on each side), FIG. 7, may be provided in the rear support block. The rear support block is provided with opposite aligned pin holes 178, FIG. 7, for supporting a scar pin 180, FIG. 3. A threaded opening 182, FIG. 7, for fastener 32 extends upwardly and slightly forwardly into the cap portion 145 through an inclined surface 184 which is terminated by transverse surfaces 185. 186 located in axially spaced relationship to the adjacent surfaces 187, 188 of the stock, FIG. 3. Block 22 is supported on the stock by rearwardly extending surface 190.

The method of assembly comprises fixedly mounting the receiver 18 on the from support block 20. Then the cylinder assembly 12 and the piston assembly 13 are positioned in the forward part of the receiver in the firing position (not shown). The spring 124 is placed over the piston rod 108 in an expanded condition. Then the spring sleeve 116 and plate 122 attached thereto are positioned on the rear of the expanded spring 124 and then moved axially forwardly against spring 124 by a suitable tool or fixture (not shown) to a position where at the rear of the plate 122-is located forward of

slots

171, 172. The rear support block 22 is then inserted in a tilted position with surface 192 extending substantially parallel to surface 130 and lugs 158, 159 located along the longitudinal axis of the tubular portion.

Lugs

158, 159 are moved along the inner surface 130 of the upper tubular portion 126 until the

lugs

158, 159 are aligned with

slots

171, 172 at which time lugs 152 have entered

slots

154, 155. Block 22 is rotated downward to bring

lugs

158, 159 into engagement with slots 17!. 172, FIG. 5. The spring sleeve 116 and plate 122 are then released and moved rcurwurdly by partially compressed spring 124 into position against block 22 which engages

surfaces

160, 161, 164, 163, 169, 170 as shown in FIG. 5.

Lugs

158, 159 are then trapped in

slots

171, 172 and thereafter bear against side surface 194, FIG. 2, of the slot whereby block 22 is held fixedly in position without further attaching means.

Trigger-Sear Assembly Referring now to FIG. 3, trigger assembly 14 is pivotally mounted on a pin 204 in a trigger cavity 205 beneath the rear support block, between the

flange portions

128, 129 of the receiver which support the trigger pivot pin 204 in opposite aligned pin holes 206 (FIG. 2), and in a slot 208 in trigger housing 34. Trigger housing 34 is a one-piece casting suspended at the forward end on transverse pin 36 by a forwardly and upwardly extending finger 210 which forms a seat 212. Assembly of the trigger housing is effected by forward and upward sliding movement onto the transverse pin 36 and then rotation thereabout to seat the rear portion 214 on a seat 216 in the stock. Fastener 32 also holds the trigger housing 34 in place.

The trigger assembly 14 comprises a main trigger casting 217 pivotally mounted by a central hub portion 218 on pin 204 for movement between a forward position as shown in FIG. 3 and a rearward release or firing position (not shown) by application of finger pressure on a depending finger lug 219. A side plate portion 220, FIG. 6, of the trigger casting extends radially about one side of hub portion 218. A rim portion 221 of the trigger casting extends transversely from the plate portion on opposite sides of the finger lug and forms a cavity 222 in which a sear release pawl 223, a pawl spring 224, and one end of a trigger-sear spring 226 are mounted and retained by a keeper plate 228. Pawl 223 has a hub portion 230 rotatably supported on the trigger hub 218 and opposite radially extending arms 232, 234. One end of the pawl compression spring 224 is seated on a lug 236 on arm 232 and the other end is seated in a spring well 238 formed in a portion 240 of the rim 221. The other arm 234 is adapted to abut the end of an adjustable screw 242 threadably mounted in a rim portion 244 and normally be held thereagainst under the influence of pawl spring 224. The purpose of this screw is to permit adjustment of the pawl for proper engagement with the sear to compensate for manufacturing tolerances and permit standardization of trigger pull'characteristics. An inspection hole 245 is provided in flange 128 to assist in this adjustment. One end of the trigger-sear spring 226 is nested in a spring well 246 formed in a rim portion 248. Keeper plate 228 has a hub portion 250 which is press fitted onto trigger hub 218 and may be staked or otherwise additionally secured to the rim portion as at 252. Trigger-sear spring 226 biases the trigger assembly to the forward position, in a clockwise direction as viewed in FIG. 3, bringing an abutment flange 254 on the trigger into engagement with the bottom of plate 122 at 255. Rearward movement of the trigger is effected against the bias of the compression spring 226.

A sear 260 is pivotally mounted on pin 180 and has a downwardly extending lug 262 and spring seat 264 which receive the other end of the trigger-sear spring 226 to exert a counterclockwise force on the sear. A notch 266 between spaced lugs 268, 270 receives the end of the piston rod with lug 268 being located in the rod notch and holding the rod in the cocked position by abutting engagement at 271. The forward bottom part of the sear extends into the trigger cavity 222 through an upwardly facing slot between the side plate 220 and the keeper plate 228. A pawl notch 272 in the bottom of the sear has a curved upper surface 274 which corresponds to the curved end surface of the arm 232 and a transverse side surface 276 which corresponds to the side of the pawl arm 232. In the latched position, pawl arm 232 is located in abutting engagement with sear surfaces 274, 276 which prevents counterclockwise movement of the sear. Pawl spring 224 has a strength sufficient to keep the sear latched until the trigger is pulled rcarwardly and the pawl arm 232 is positively moved out of abutting engagement with sear surfaces 274, 276. Counterclockwise movement of the sear is limited by an abutment surface 278 on the rear of the sear and an abutment surface 280 on the rear support block.

When the trigger is pulled rearwardly, screw 242 forces the pawl 223 to be rotated therewith counterclockwise and the arm 232 is moved out of the sear notch 272 whereupon the compression spring 124 drives the piston and piston rod forward causing the sear 260 to be cammed downwardly counterclockwise to a release position with sear front side surface 282 engaging arm rear side surface 284 and rear sear abutment surface 278 engaging the support block surface 280. The sear is held in the fired position by spring 226 until the piston rod is moved rearwardly during a cocking cycle whereupon the rear rod surface 114 passes over the depressed front sear lug 268 and engages the front surface of rear sear lug 270. The sear is cammed in a clockwise direction against the bias of the spring 226 causing the front sear lug 268 to move upwardly into latching engagement in the rod notch 110 and allowing the pawl arm 232 to move back into blocking engagement with the sear surfaces 274, 276 in the sear notch 272 under the influence of pawl spring 224. Trigger abutment 254 engages the bottom of plate 122 at 255 and holds the trigger in the forward cocked position. The relatively movable trigger casting 217 and pawl 223 are statically balanced and biased by springs 224, 226 so that, if the gun is bumped, jarred, or dropped in any attitude, there will be no forces actuable upon the trigger to cause the gun to accidentally discharge.

Safety Assembly Referring now to FIG. 6, trigger safety 290 comprises a slide plate 292 and a keeper plate 294. The slide plate has a main elongated body portion 296 slidably supported on receiver flange 128 at one end as by trigger pivot pin 204 received in an elongated slot 298, and at the other end as by an integral receiver flange tab 300 received in another elongated slot (not shown). A transverse abutment flange 302 extends through a slot 304 in the receiver for blocking engagement with trigger abutment surface 306 in the on position shown in FIG. 6. Keeper plate 294 is made of spring steel material and also mounted on trigger pivot pin 204 at one end and tab 300 by means of a T-shaped slot 308 at the other end. The base portion 310 of the keeper plate is formed offset to the finger portion 312 so that, in the assembled position, a spring force is ex-' erted against the safety. integrally formed dimples 313, 314 on the keeper plate cooperate with a detent (not shown) on the safety to hold the safety in the on-off positions. Manual move ment of the safety between the on-off positions is effectuated by means of a thumb plate 315 on the end of a flange 316 which is outwardly curved to conform to the curvature of the receiver and extends upwardly through a slot (not shown) between the stock and the receiver at the top of the gun. The safety is also automatically movable to the on position during the cocking cycle by engagement of the rear edge 317 of the cylinder 12 with a flange 318 extending through a slot 319 in the receiver 18 into the path of movement of the cylinder.

Cocking Assembly Referring again to FIG. 1, the cocking lever assembly 16 is mounted in an elongated slot 320 in the bottom of the forearm. A manually operable actuating lever 322 is channel shaped with a base portion 324 extending between spaced parallel flange portions 326 (there being one on each side). An abutment and handle plate 328 is welded on the forward end of the lever between the flanged portions. The rear end of the lever is pivoted on pin 36 which extends through aligned holes 329, 330 in receiver ear portions 331, 332. The lever flange portions 326 are located between the receiver flange portions 331, 332 and are notched at 334 to accommodate a spacer pin and bushing 336 in the stowed position. The spacer pin is mounted in opposite aligned openings 338 in the receiver flanges. A channel-shaped drag link 340 having a base portion 342 and spaced flange portions 344 is pivotally connected at one end to the cylinder head by pin 48 extending through link flange portions 344 and at the other end to lever 322 by a pin 348 extending through lever flange portions 326. A lever latch means is provided by a spring clip 350 mounted on lever base portion 324 and extending upwardly for latching engagement with link base portion 342 through a latch slot 352. An additional safety feature is provided byan abutment surface 360, FIG. 3, on the rear end of one of the lever flanges 326 which is located in blocking relationship to trigger surface 362 on flange 254 whenever the cocking lever is not in the stowed position to prevent rearward movement of the trigger.

When the cocking lever is moved from the retracted stowed position of FIG. 1, pivot pin 348 is moved downwardly and rearwardly on an arc about pivot 36. The rear end of link 340 is also moved downwardly and rearwardly while the path of movement of the front end of the link is restricted to a rearwardly direction since pivot pin 48 is attached to the cylinder assembly and the movement of the cylinder assembly is confined by the tubular guide portion 130 of the receiver. The cylinder assembly is thus moved rearwardly and pushes the piston assembly rearwardly from a fired position adjacent the cylinder head to the latched cocked position of FIG. 1 in latched engagement with the sear as hereinbefore described. The piston spring 124 is simultaneously compressed. The cocking lever is then returned to the stowed position which moves the cylinder assembly back to the firing position of FIG. 1 and unlocks the trigger for firing. During the final movement of the cocking lever, the latch spring clip 3S0 enters slot 352 and is sprung over the base portion 342 of the link to hold the cocking lever against the bottom of the stock at 364.

It is contemplated that the inventive concepts hereinbefore described may be variously otherwise embodied and combined without departing from the inventive principles involved and intended to be covered by the appended claims, except insofar as limited by the prior art those inventive principles rendered obvious thereby.

lclaim:

1. In a firearm having an air ignition system including an air compression cylinder means and an ammunition holding means relatively movable between an adjoining location in a firing position and an axially spaced location in a loading position and having a firing chamber located therebetween in the firing position, the invention comprising:

an outer annular obturation rim surrounding the firing chamber and extending rearwardly from said ammunition holding means and terminating in a rearwardly facing transverse rear end surface; 4

a rearwardly facing abutment surface on said ammunition holding means extending outwardly of said outer annular obturation rim and located forwardly of said rearwardly facing transverse rear end surface;

a first rearwardly opening annular chamber located within said outer annular obturation rim and terminating in a transverse rearwardly facing end surface;

an inner annular obturation rim surrounding the firing chamber and extending forwardly from said air compression cylinder means and terminating in a transverse for ward end surface; forwardly opening annular obturation chamber located outwardly circumjacent said inner annular obturation rim and defined by an outwardly spaced axially extending annular surface and a rear forwardly facing transverse surface and being axially aligned with and matingly receiving saidouter annular obturation rim in the firing position;

a second rearwardly opening annular chamber located inwardly circumjacent said outer annular obturation rim and being axially aligned with said first rearwardly opening annular chamber and matingly receiving said inner annular obturation rim in the firing position;

a forwardly facing abutment surface on said air compression cylinder means extending outwardly of said forwardly opening annular obturation chamber and being located forwardly of said rear forwardly facing transverse surface and axially aligned and located adjacent said rearwardly facing abutment surface on said ammunition holding means in the firing position;

the length of said outer annular obturation rim from said rearwardly facing abutment surface to said rearwardly facing transverse rear end surface being less than the length of said forwardly opening annular obturation chamber from said forwardly facing abutment surface to said rear forwardly facing transverse surface so that in the firing position the rearwardly facing transverse rear end surface is axially spaced from the rear forwardly facing transverse surface, said inner annular obturation rim extending within said second rearwardly opening annular chamber, the transverse forward end surface of said inner annular obturating rim being located adjacent the transverse rearwardly facing end surface of said first rearwardly opening annular chamber;

the outside diameter of said inner annular obturation rim being slightly less than the inside diameter of the second rearwardly opening annular chamber so as to provide primary obturation therebetween; and

the outside diameter of said outer annular obturation rim being slightly less than the inside diameter of the forwardly opening annular obturation chamber so as to provide secondary obturation therebetween.

2. In a firearm having an air ignition system including an air compression cylinder and ammunition holding means, the invention comprising:

a plug member for connecting said air compression cylinder to said ammunition holding means;

a cylinder head at the front of said compression cylinder;

a bore of varying diameter extending axially through said cylinder head;

said bore having an end portion of smallest width next adjacent the rear of said cylinder head;

an intermediate portion of larger width;

a transversely extending plug seat connecting said end portion to said intermediate portion;

the outer periphery of said plug member having a first portion of smallest width corresponding in size and shape to said first end portion of smallest width of said bore and being mounted therein;

a second portion of larger width corresponding in size and shape to said intermediate portion of said bore and being mounted therein, a transversely extending abutment connecting said first portion to said second intermediate portion and being seated on said transversely extending plug seat;

intermediate portion, said plug member extending therewithin and being radially inwardly spaced therefrom and defining an obturation chamber therebetween.