US2997924A

US2997924A - Firearm with fortary magazine and pivoting rear barrel section

Info

Publication number: US2997924A
Application number: US47724A
Authority: US
Inventors: Waldo E Rosebush
Original assignee: Individual
Current assignee: Individual
Priority date: 1960-08-05
Filing date: 1960-08-05
Publication date: 1961-08-29
Anticipated expiration: 1978-08-29

Description

Aug. 29, 1961 w. E. ROSEBUSH 2,997,924

FIREARM WITH ROTARY MAGAZINE AND PIVOTING REAR BARREL SECTION Filed Aug. 5, 1960 3 Sheets-Sheet 1 7 if A? gr INVENTOR .T/QOSEBUSH ATTORNEY 1961 w. E. ROSEBUSH 2,997,924

FIREARM WITH ROTARY MAGAZINE AND PIVOTING REAR BARREL SECTION Filed Aug. 5, 1960 3 Sheets-Sheet 2 02 7.2 4:1 93 /0/ l; 2a 33 /aa m6 L' I 4 /7x /1/ 11/777 Ill/I77 I l INVENTOR Wit/Po 555(15/4 ZKKW ATTORNEY Aug. 29, 1961 w. E. ROSEBUSH FIREARM WITH ROTARY MAGAZINE AND PIVOTING REAR BARREL SECTION Q 3 m? v Q mw m \x m\\ m m Nw s 3 \k m mm m. Q mu 3 mm 0 AR km 3 a Q Q I M XW/ J .1 HQ .0 91 mi? NR- 9 1 n3 A NQRQ g L m m NM 1 m WITH ROTARY MAGAZINE AND PIVOT- ING REAR BARREL SECTION Waldo E. Rosebush, 41 1 Washington St., Appleton, Wis. Filed Aug. 5, 1960, Ser. No. 47,724 11 Claims. (Cl. 89-155) This invention relates to a novel construction of firearm having a rotary magazine provided with a plurality of chambers each adapted to contain a number of cartridges and whereby the capacity of the magazine may be increased considerably without an appreciable increase in the over-all size of the piece.

Another object of the invention is to provide a firearm including a hingedly mounted barrel section which is movable to a position in alignment with a chamber of the magazine for receiving a cartridge therefrom and thereafter to a position in alignment with the stationary barrel section, for firing of the piece.

A further object of the invention is to provide a firearm wherein said movable barrel section is connected to and moves in unison with a trigger.

Still another object of the invention is to provide a firearm having novel means to automatically turn the rotary magazine, after each chamber thereof is emptied, to align another chamber of the magazine, containing cartridges, with the hinged barrel section, when said barrel section swings to a position for receiving a cartridge from the magazine.

Still a further object of the invention is to provide a firearm having a novel form of ejector operating through the firearm hammer for ejecting the cartridge cases automatically from the bolt and bolt housing during rearward recoil travel of the bolt.

Various other objects and advantages of the invention will hereinafter become more fully apparent from the following description of the drawings, illustrating a presently preferred embodiment thereof, and wherein:

FIGURE 1 is a side elevational view showing the improved firearm in the form of an automatic pistol and looking toward the left side thereof;

FIGURE 2 is a top plan view of the pistol;

FIGURE 3 is an enlarged fragmentary longitudinal sectional view, partly in side elevation, showing parts of the pistol in the positions assumed thereby, immediately after firing of the piece and during ejection of the empty cartridge case;

FIGURE 4 is a view similar to FIGURE 3, illustrating the position of the parts immediately prior to firing of the piece;

FIGURE 5 is an enlarged longitudinal sectional view, partly in side elevation, showing certain of the parts of the pistol in the positions assumed by the parts for feeding a cartridge from the magazine to the barrel;

FIGURE 6 is a fragmentary side elevational view, partly broken away and partly in section, illustrating the relationship of the parts, constituting the magazine actuator, to one another;

FIGURE 7 is an end elevational view looking toward the rear end of the barrel and the hinged carrier thereof;

FIGURE 8 is an elevational view, partly in section, looking toward the forward end of the magazine and illustrating one position of the parts of the magazine actuator;

FIGURE 9 is a cross sectional view through the magazine and magazine housing, taken substantially along a plane as indicated-by the line 9-9 of FIGURE 5;

FIGURE 10 is an end elevational view, on areduced scale, of the magazine and magazine housing, looking from right to left of FIGURE 5;

i United States Patent 0 2,997,924 Patented Aug. ,29, 1961 FIGURE 11 is a front elevational view of the hammer, on a reduced scale, relative to FIGURES 3 to 5;

FIGURE 12 is a rear elevational view of the hammer;

FIGURE 13 is a side elevational View of the hammer and showing the ejector extending therethrough, and

FIGURE 14 is a fragmentary view similar to FIGURE 8 and illustrating a different position of the magazine actuating parts.

Referring more specifically to the drawings, the firearm in its entirety is designated generally 15 and is illustrated in the form of an automatic pistol, preferably of small caliber; however, as the description proceeds it will be readily apparent that the invention is equally well adapted to other types of automatic firearms such as rifles. The pistol 15, as illustrated, is of .22 caliber.

The pistol 15 includes a frame, designated generally 16, having an elongated top and forward portion 17, constituting one end thereof, a guard strap v18, constituting the other end of said frame, and a trigger guard 19 extending between the frame portion 17 and the guard strap 18.

The forward and top frame portion 17 is recessed as seen at 20, said recess 20 opening upwardly therethrough and extending to adjacent a front face 21 of the portion 17 and through an arcuate concave rear end 22 thereof. The forward end of the recess 20 is of reduced depth and has an upwardly facing shoulder 23.

A forward and stationary barrel section 24 is provided adjacent its forward muzzle end with a depending boss 25 which fits snugly in the forward end of the recess 20 and has a part of its lower end resting on the upwardly facing shoulder 23. A pin 26 extends transversely through a forward part of the frame portion 17 and through an opening 27 of the boss 25 for detachably securing the barrel section 24 immovably to the frame portion 17. The barrel section 24 has an enlargement or collar 23 at its rear end which is provided with depending transversely spaced aligned hinge barrel portions 29 which are located behind and spaced from the rear end 22 of the frame portion 17.

A carrier member, designated generally 30 and best seen in FIGURES 5, 6 and 7, has a substantially straight top portion 31, the forward end of which fits turnably between the hinge portions 29 and is pivotally connected thereto by a bushing 32 surrounding a pin 32', to form a hinge or knee joint between said end of the carrier 30 and the rear end of the stationary forward barrel section 24. A rear barrel section 33 is mounted on and fixed immovably to the upper or outer edge of the top carrier portion 31 for swinging movement therewith and has a forward end 34 which abuts flush against the rear end of the barrel section 24, in a fully raised position of the carrier 30, as seen in FIGURES 3, 4 and 6, and in which position the bore 35 of the rear barrel section 33 aligns fully with the bore 36 of the forward barrel section 24, both of which bores are rifled and with the riding of one constituting a continuation of the rifling of the other. The carrier 30 includes a rear portion 37, as best seen in FIGURE 6, which extends downwardly from the rear end of the barrel section 33 and which is curved so that its outer or rear face 38 is disposed concentric with the hinge axis 32.

A trigger housing is composed of complementary side plates 39 which are secured to opposite sides of the carrier 30 by pins 40. The side plates 39 have back edges 41 which are disposed flush with the rear face 38 of the carrier portion 37, and said plates 39 have concavely arced forward edges 42 between which a trigger 43 is secured by pins 44. The trigger 43 is located beyond the lower free end of the rear carrier portion 37, as seen in FIGURE 6.

One end of a contractile coil spring 45 is anchored be- -other and from the axis of said magazine.

tween the side plates 39 by a pin 46, which extends therethrough, said spring end being disposed above the trigger 43, as seen in FIGURE 4. The spring 45 extends forwardly from the trigger housing 39 longitudinally through the recess 20 and is anchored at its opposite end to a stud 47, forming an integral part of the frame portion 17 and which extends upwardly into the recess 20. A part of the boss 25 rests on the stud 47 to prevent the forward end of the spring 45 from being disengaged over the upper end of said stud, when the boss 25 is secured to the frame 16.

A sear 48 has an opening 48 to loosely receive a lug '37 which projects from a part of the forward edge of the rear carrier portion 37, said sear 48 being pivotally mounted at a point spaced from its ends on a pivot pin 49 which engages through the sear and said lug 37'. The sear 48 is disposed between the side plates 39, forwardly of the carrier portion 37, and has transversely spaced fingers 50 constituting the upper end thereof and which straddle and are swingably movable relative to the carrier portion 31 and which are disposed for swinging movement in corresponding notches 51 of the side plates 39 and recesses 52 in the underside of the barrel section 33.

The rear carrier portion 37 has a recess 53 extending from front to rear therethrough and which opens outwardly of its back face 38, as seen in FIGURE 7, in which a lever 54 is mounted for swinging movement on a pin 55, which pivotally connects said lever to the carrier portion 37, for swinging movement of the lever through said rear face 38. A compression spring 56 extending through a forward part of recess 53 engages between parts.

of the sear 48 and lever 54 for urging both the lever and sear to swing clockwise about their pivots, as seen in FIGURE 6, since the spring 56 engages the lever 54 above its pivot 55 and the sear 48 below its pivot 49.

The pistol 15 includes complementary side plates 57 and 58. The right hand side plate 58 carries the pins 26 and 32' which connect with the left hand side plate 57. Screws 60 engage loosely through plate 57 and frame 16 and threadedly engage in the side plate 58. A back strap 61 is secured between rear edges of the side plates 57 and 58 by pins 62 and has a rearwardly curved lower portion extending downwardly below the coplanar bottom edges 63 of said plates 57 and 58. The back strap 61 is spaced from the guard strap 18 and the plates 57 and 58 have transversely aligned corresponding notches 64 which open downwardly through their bottom edges 63, between said guard strap 18 and back strap 61.

A hollow one piece grip 65 embraces the notched bottom rear portions of the plates 57 and 58 and has a forwardly opening groove 66 accommodating the guard strap -18 and a rearwardly opening groove 67 accommodating the back strap 61. The grip 65 has a recess 68, extending from top to bottom thereof, of circular cross section for detachablyreceiving a cylindrical magazine housing 69, parts of which engage through the notches 64. The grip -65 is detachably secured in position by a wood screw 65' which engages through the guard strap 18.

A magazine 70 fits rotatably in the housing 69 and is provided with five chambers 71 which extend from endto-end thereof and which are equally spaced from one an- As seen in FIGURE 8, the magazine housing 69 has a front wall 72 which is provided with a central opening 73 and an opening 74 which extends radially inward from a part of its periphery and which is spaced from the opening 73. The opening 74 is disposed to selectively align with the chambers 71 as the magazine 70 is revolved in the housing 69.

73 and from which a threaded stem 77 projects. The

stem 77 threadedly engages a centrally disposed socket 78 which opens outwardly of the forward end of the maga- --zine 70, so that the ratchet wheel 75 rotates with the maga- 4 i zine and relative to the housing 69 about the boss 76 as an axis; however, the magazine 70 has a relatively close fitting engagement in the housing 69, as seen in FIGURES 5 and 9. When the housing 69 containing the magazine 70 is mounted in the pistol 15,'as seen in FIGURES 1 and 5, the housing front wall 72 is disposed in close prox imity to the carrier face 37 with only slight clearance between said carrier face and the-ratchet wheel 75.

Each of .the chambers 71 contains a follower 79 and a follower spring 80 for feeding cartridges 81 therefrom through the opening 74, when the chamber of said magazine is in alignment with said opening. The cartridges 81 are .22 caliber short cartridges and each chamber v71 is adapted to contain three cartridges; however, the magazine 70 could be constructed to hold a greater or lesser number of cartridges in each of its chambers 71.

A hammer, designated generally 82, is mounted for swinging movement on a pivot pin 83 between the side plates 57 and 58 and above and behind the upper portion of the magazine housing 69. The pin 83 is supported by said side plates 57 and 58, and engages through the ham mer 82 near the lower end of the hammer. Hammer 82 has a forwardly extending nose 84 near its upper free end and an opening 85 which extends from front to rear therethrough, below the nose 84. The hammer 82 has a forwardly opening recess 86 extending from its bottom through a front portion located beneath and adjacent the forward end of the opening 85, and said hammer has complementary toes 87 extending from its forward edge, on opposite sides of the recess 86, As best seen in FIG- URES 3 and 4, the outer faces of the upper and rear portions of the trigger side plates 39 are recessed, as seen at 88, and the toes 87 straddle and slidably engage said recessed portions so that the tips of the toes 87 contact the sear fingers 50 which protrude outwardly from the planes of the recessed surfaces 88, as will hereinafterbe described. A spring actuated guide 89 i pivotally mount ed for rocking movement in the hammer recess 86 on a pivot pin 90 which engages through said guide 89 nearer the lower end than the upper end thereof. A light compression spring 91 seats in a socket 92 of the hammer 82, which opens into the recess 86, and the spring 91 bears against the inner side of the guide 89 above its pivot 90.

A bolt 93 of arch shape cross section has an internally restricted forward portion 94 which engages around the forward barrel section 24 and which provides a rearwardly facing arch shaped shoulder 95 which bears against a forward end of a recoil spring 96 which is mounted loosely on the barrel section 24 and which has a rear end abutting against the collar 28. The bolt 93 has a rear end wall 97 which is provided with a vertically elongated opening 98 and a downwardly opening notch 99, which is disposed beneath and in alignment with the opening 98. The bolt 93 has an externally thickened knurled top portion 100 which extends forwardly from the rear wall 97 to a point spaced from the forward end of said bolt, and the rear end of said thickened top portion is provided with a vertically elongated ejector opening 101. A rear sight 102 is secured to and extends upwardly from the rear wall 97 and is detachably fastened to the bolt 93 by a screw 103. An extractor 104 is formed integral with the base portion of the rear sight 102 and extends downwardly therefrom through the rear portion of the opening 101 and across the upper part of the opening 98. When the rear barrel section 33 is in alignment with the forward barrel section 24, as seen in FIGURE 4, the rear wall 97 of the bolt is disposed behind the rear end of the rear barrel section 33 and the lower portion of the extractor 104 bears against the inclined rear surface 105 of the barrel section 33, when the bolt 93 is in its forwardmost position of FIGURE 4. t

Referring to FIGURE 5, an arm 106 forming a spring stop is formed integral with and extends forwardly from an upper part of the back strap 61 and has an opening 107 extending from top to bottom therethrough. An elongated latch member 108 has a rocking engagement in a forwardly opening groove 109 of the back strap 61. The latch 108 has furcations 110 at its upper end straddling the spring stop 106 and pivotally connected thereto by a pivot pin 111 located adjacent the forward end of said spring stop and the forward ends of said furcations. The latch member 108 includes a bridge 112 which spans the upper edges of the inner ends of the furcations 110 and which is disposed above and spaced from the inner portion of the spring stop 106. The latch 108 has a head 113 at its lower free end which is disposed beyond the lower end of the back strap 61 and which is provided with an inwardly opening socket or recess 114.

The hammer 82 has a downwardly and rearwardly opening socket 115 in its rear side and above its pivot 83 in which the hemispherical head 116 of the pin 117 has a rocking engagement. Pin 117 forms a guide for a coiled compression spring 118 which is mounted thereon and the upper end of which bears against the fiat underside of the head 116. The lower end of the spring 118 bears against the upper side of the spring stop 106 and a part of the bottom convolution of said spring bears on the bridge 112 for urging the latch 188 to rock inwardly and away from the back strap 61 about its pivot 111. The guide pin 117 extends loosely through the opening 107 of the spring stop.

The magazine housing. 69 has a knurled enlargement 119 at its lower end and the magazine 70 has a knurled bottom portion 120 which protrudes from the lower end of the housing 69. The bottom end of the magazine 70 is also provided with a kerf 121, as seen in FIGURE 10. A lug 122 projects from the underside of the knurled portion 119 and is spaced slightly from the knurled peripheral portion 120, so that said lug will not interfere with rotation of the magazine 70. The lug 122 conformably seats in the recess 114 for latching the housing 69 im movably in the pistol 15 and with the opening 74 thereof in alignment with the bore 35, when the barrel section 33 is in its inclined position of FIGURE 5. Thus, the housing 69 can only be latched in the piston 15 in this one predetermined position. The latch head 113 is manually engaged and displaced outwardly for applying the housing 69 and magazine '70 to the pistol or for removing them therefrom.

The coplanar bottom edges 123 of the bolt 93 slidably engage and ride on the coplanar top edges 124 of the side plates 57 and 58. The bolt 93 is held applied to the forward barrel section 24 by a bolt housing 125 of arch shape cross sect-ion, as seen in FIGURES 1 and 2 and partially in FIGURE 3. The housing 125 has substantially parallel side walls 126 which straddle the bolt 93 and upper portions of the side plates 57 and 58. The side walls 126 have forwardly opening notches 127 in which the ends of the pin 26 engage for connecting the forward end of the housing 125 detachably to the frame 16. A single screw fastening 128 extends through one of the side walls 126 and is threaded into the side plate 57 or 58, disposed adjacent thereto, for detachably holding the housing 125 immovable on the pistol, in cooperation with the pin 26. The housing 125 has an opening 129 extending from near the forward end of its rounded top portion 130 downwardly to adjacent the lower end of its vertically rounded rear wall 131. The partof the opening 129 formed in the top wall 130 slidably receives the externally enlarged portion 100 of the bolt 93, the forward end of which engages the forward end of the opening 129 to limit forward movement of the bolt under the biasing action of the recoil spring 96 and to thus nor mally maintain the bolt in its position of FIGURE 4. The top portion 130 is provided with a front sight 132 which is disposed forwardly of the opening 129.

An ejector 133 has a rear end pivotally mounted in a forwardly opening recess 134 of the rear wall 131 on a pin 135, said recess being disposed beneath the lower rear endof the opening 129. The ejector 133 extends forwardly from its pivot 135' through the hammer opening 85. The ejector 133 has a cam surface 136 on its underside for engaging the rear surface of the hammer 82 and thereafter the bottom surface of the opening so that the ejector is swung upwardly as the hammer swings rearwardly. The upper edge of the ejector 133 is provided with a forwardly facing shoulder 137 which is disposed forwardly of the cam surface 136 but spaced from the forward, free end of said ejector.

The bottom wall 131 of the bolt housing has a forwardly extending lip 138, as seen in FIGURE 5, which engages rearwardly opening notches 139 in the side plates 57 and 58 to additionally maintain the housing in an applied position, and which lip 138 is disengaged from the notches 139 as the housing 125 is displaced rearwardly, after removal of the screw 128, for disengaging the notches 127 from the pin 26.

As best illustrated in FIGURES 6 and 7, the lever 54 is provided intermediate of its ends with a laterally offset upwardly extending integral pawl 140, the tip of which is outwardly offset from the adjacent portion of the outer surface of said lever, as seen in FIGURE 6. The outer surface of the lever 54, above the pawl 140, is recessed as seen in FIGURE 7 to clear the lug of ratchet wheel 75 with which it aligns.

FIGURE 1 shows the pistol 15 ready to be fired, assuming that the magazine 70 contains cartridges 81 in the chambers 71 thereof. The spring 45 urges the strigger 43 and trigger housing 39 to swing to its position of FIGURE 1, which corresponds to the position of said parts in FIGURE 5, in which position the rear barrel section 33 is disposed in alignment with the opening 74. The follower 79 and spring 80 of the chamber 71, which is in alignment with the opening 74, will feed the forwardmost cartridge from said chamber 71 into the breech of the barrel section 33, as seen in FIGURE 5. When the trigger 43 is thereafter pulled rearwardly, toward its position of FIGURES 3 and 4, the trigger housing 39, carrier 30 and barrel section 33 will swing from their positions of FIGURE 5 to their positions of FIGURE 4, with the cartridge 81 contained in the breech 35 being carried upwardly to its position of FIGURE 4. The outer portion of each chamber 71 and the side wall of the housing 69, in alignment with the opening 74, are recessed or notched as seen at 142 to permit passage of the flange 143 of the cartridge case therethrough. As said cartridge travels upwardly with the barrel section 33, the base thereof will engage and ride over the cam surface 144 of the guide 89 to fully seat said cartridge in the breech, the guide 89 yieldably rocking about its pivot and against the action of its spring 91 to permit the cartridge base 143 to pass in front of the cam surface 144.

As the barrel section 33 commences to move upwardly between the hammer toes 87, the upper ends of the sear fingers engage under said hammer toes to rock the hammer 82 rearwardly about its pivot 83. As the barrel section 33 reaches its fully raised position in alignment with the barrel section 24- the hammer toes clear the upper ends of the sear finger 50 for releasing the hammer 82 from its fully cocked position of FIGURE 4. As the hammer commences its forward swinging movement under the action of the compressed hammer spring 118, the tips of, the toes 87 ride down the rear edge of the sear fingers 50 to cause the sear to rock counterclockwise about its pivot 49 for swinging the sear fingers 50 forwardly. The hammer nose 84 is propelled through the opening 98 to strike the base 143 of the cartridge 81 contained in the breech 35 for detonating said cartridge to effect firing of the piece 15.

It will be noted that the extractor 104 engages in front of the top portion of the cartridge base 143 when the cartridge 81 is in its battery position of FIGURE 4. Accordingly, when the piece is fired the bolt 93 is driven rearwardly by the recoil from its position of FIGURE 4 toward its position of FIGURE 3. As the rear Wall 97 of the bolt is in. engagement with the hammer. 82, the

hammer will be swung back from its forward position, approximately as shown in FIGURE 5, and as seen' in FIGURES l and 2, toward its position of FIGURE 3. The empty case 145 will be withdrawn from the breech 35, by the extractor 104 and as it moves rearwardly the bottom portion of its base 143 will strike the forwardly facing ejector shoulder 137, as said ejector is swung Upwardly, by rearward swinging movement of the hammer 82, for ejecting the empty case 145 from the pistol 15 through the bolt opening 101 and the housing opening 129.

During rearward movement of the hammer 82, caused by recoil of the bolt 93, the hammer toes 87 will swing upwardly in the recesses 88 to engage the rear edges of the fingers 50, which have been returned to their normal positions of FIGURES and 6 by the sear spring 56, to again cause the sear 48 to rock counterclockwise about its pivot 49 as the fingers 50 are swung forwardly by the toes 87 to their positions of FIGURE 3.

The recoil spring 96, by engagement with the shoulder 95, will immediately return the bolt 93 to its forward position of FIGURES l, 2 and 4 after extraction and ejection of the empty cartridge case 145 has been accomplished, and the trigger spring 45 will, immediately thereafter, return the

parts

30, 33 and 39 to their positions of FIGURES 1 and 5 so that another cartridge 81 can be fed into the breech 35 in order that firing of the piece, as previously described can be repeated.

As the

parts

30, 33 and 39 swing upwardly from their positions of FIGURE 5, if there is another cartridge 81 in the chamber 71 which is-in alignment with the opening 74, said cartridge will be advanced so that the nose thereof will protrude through the opening 74 for engaging the cam surface 141 of the lever 54 to hold said lever seated in the recess 53 until the pawl 140 has cleared the lug 147 of the ratchet wheel 75, which is in the path of travel of said pawl, as seen in FIGURE 8. Thereafter, the sear spring 56 will swing the lever 54 outwardly to its full line position of FIGURE 6. However, as the parts again swing downwardly, the exposed cartridge nose 148 will again swing the lever 54 inwardly to its dotted line position so that the pawl 140 will not touch the ratchet wheels 75.

As the parts swing upwardly, after the last cartridge 81 has been fed from a chamber 71 into the breech 35, there will be no cartridge nose to engage the cam surface 141. Accordingly, the lever 54 will swing outwardly to its full line position of FIGURE 6 before the pawl 140 reaches the ratchet Wheel 75 so that the pawl will engage the ratchet lug 147 for turning said lug, the ratchet wheel 75 and magazine 70 one-fifth of a revolution relative to the housing 69, to move another chamber 71 con- .taining cartridges 81 into alignment with the opening 74. The lug 147 is shown in FIGURE 14 engaged by the pawl 140 and after it has completed a partof its one-fifth revolution and before being disengaged by said pawl.

The knurled ring 119 enables the housing 69 to be held immovable while the magazine 70 is rotated by gripping the knurled surface 120 for reloading the magazine 70 through opening 74, when the housing 69 and magazine 70 are removed from the pistol 15. The kerf 121 can be engaged by a tool for holding the magazine while unscrewing the ratchet wheel 75.

Various modifications and changes are contemplated and may be resorted to, without departing from the function or scope of the invention as hereinafter defined by the appended claims.

I claim as my invention:

1. In a semi-automatic firearm, a rotary magazine having a plurality of chambers each adapted to contain cartridges, a spring pressed follower in each of said chambers for feeding the cartridges therefrom, a barrel having a stationary front section and a rear section, a carrier pivotally connectedto said front. section and secured to said rear section for swinging movement of the rear section with the carrier between an aligned position of the barrel sections and a position in which the rear barrel section is in alignment with one chamber of the magazine for receiving a cartridge therefrom.

2. In a firearm as defined by claim 1, said barrel sections having bores disposed in alignment with one another, when the barrel sections are aligned, said bores being rifled and the rifling of the bore of the forward barrel section constituting a continuation of the rifling of the bore of the rear barrel section.

3. In a semi-automatic firearm as defined by claim 2, a cylindrical housing detachably mounted in a part of the firearm and in which said magazine is rotatably mounted, said housing having a front wall provided with an opening disposed to selectively align with the magazine chambers and through which the cartridges are fed to said rear barrel section.

4. In a semi-automatic firearm as defined by claim 3, a ratchet wheel secured to said magazine and rotatably mounted beyond said housing wall, a lever pivotally connected to and carried by said carrier and having a pawl, spring means bearing against said lever for urging the lever and pawl to swing outwardly of the carrier for posi tioning the pawl to engage and turn the ratchet wheel and magazine as the carrier swings in a direction for moving the rear barrel section into alignment with the front barrel section, and said lever having a cam surface engaged by the nose of a cartridge remaining in said magazine chamber to hold the pawl out of engagement with the ratchet wheel, to prevent turning of the magazine, when at least one cartridge remains in the chamber which is in alignment with said housing opening.

5. In a semi-automatic firearm as in claim 1, a trigger connected to said carrier for swingably moving the rear barrel section, with the carrier, out of alignment with said magazine chamber and into alignment with said front barrel section, and a trigger spring for returning said parts to their original positions with the rear barrel section in alignment with said magazinechamber.

6. In a semi-automatic firearm as defined by claim 5, a hammer, means pivotally mounting said hammer behind said carrier for swinging movement of an upper portion of the hammer toward and away from the barrel, a hammer spring engaging the hammer and urging the upper portion thereof to swing toward the barrel, and a spring pressed sear supported by the carrier for engaging a part of the hammer as the carrier is moved by manipulation of the trigger for swinging the hammer away fi-om the barrel and to a cocked position and for releasing the hammer, when the barrel sections are disposed in alignment, to effect firing of the piece by the hammer striking the cartridge contained in said barrel section.

7. In a semi-automatic firearm as defined by claim 6, a bolt slidably mounted on said front barrel section having a rear wall forming a breechblock and provided with an opening in which a part of the hammer moves for striking the cartridge, a recoil spring mounted on the front barrel section and engaging a part of the bolt to resist rearward recoil movement of said bolt and to return the bolt to a forward position, said bolt havingan ejector opening, an extractor carried by the bolt to engage and remove the empty cartridge case from the rear barrel section during recoil of the bolt, and an ejector for ejecting the extracted cartridge case through said bolt opening.

8. In a semi-automatic firearm as defined by claim 7, a bolt housing disposed over said bolt and in which said bolt is slidably movable, means pivotally connecting a rear end of said ejector to said bolt housing, and said hammer and ejector having coacting cam portions for swinging the ejector upwardly as the hammer is swung rearwardly by rearward recoil movement of the bolt for effecting the cartridge case ejection.

9. In a semi-automatic firearm as defined by claim 8,

said hammer having an opening through Which said ejector operates.

10. In a semi-automatic firearm as defined by claim 1, a cylindrical housing detachably mounted in a part of the firearm and in which said magazine is rotatably mounted, said housing having a front wall provided with an opening disposed to selectively align with the magazine chambers and through which the cartridges are fed to said rear barrel section, and a spring projected latch member detachably engaging a part of said housing for detachably latching the housing in the firearm with said front wall opening disposed to align with a bore of the No references cited.