RIFLE CONVERSION ASSEMBLY

• US 3,771,415 A
• Filed: 02/07/1972
• Issued: 11/13/1973
• Est. Priority Date: 02/07/1972
• Status: Expired due to Term

• Current Assignee: Colt Licensing Limited Partnership A de Limited Partnership
• Original Assignee: Henry A. Into, Richard L. Costello
• Inventors: Into, Henry A., Costello, Richard L.
• Primary Examiner(s): Bentley, Stephen C.
• Application Number:
  US05/224,208
• Time in Patent Office: 645 Days
• Field of Search: 42/77 89/14R,16,29,128,194,197,198,199
• US Class Current: 89/16
• CPC Class Codes: F41A 11/02 Modular concepts, e.g. weapon-family concepts
• CPC Class Codes: F41A 15/14 the ejector being mounted on or within the bolt; Extractors per se
• CPC Class Codes: F41A 3/78 Bolt buffer or recuperator means

Abstract

An assembly is provided for converting a firearm of standard caliber to one of a smaller caliber and includes a conversion chamber adaptor with a bolt mounted for movement between recoil and battery positions. A backplate damper assists in maintaining the operating components in assembly and absorbs recoil impact energy of the recoiling mass upon firing of the weapon. When the conversion assembly is installed in a weapon having a buffer disposed rearwardly of its chamber, the backplate damper additionally serves to transmit that energy to the buffer.

Claims

1. A firearm conversion assembly detachably insertable into a chamber of a firearm receiver upon removal of its standard bolt means for converting the firearm to fire ammunition of a caliber smaller than its standard caliber and comprising a conversion chamber adaptor insertable into the firearm chamber in fixed relation thereto, a bolt, a backplate damper, detachable mounting means releasably mounting the adaptor, bolt and backplate damper in a unitary assembly and including a guide rod detachably connecting the bolt and the backplate damper in assembled relation and supporting the bolt and the backplate damper on the guide rod, the bolt and the backplate damper being reciprocable on the guide rod with the bolt movable between a forward battery position in engagement with the conversion adaptor and a rear recoil position, the guide rod establishing a rear limit position for the backplate damper and cooperating therewith in establishing the rear recoil position of the bolt, and an action spring supported on the guide rod with opposite ends of the spring seated on the bolt and the backplate damper, the spring urging the bolt forwardly toward battery position and urging the backplate damper toward its rear limit position, the backplate damper being engageable with the bolt and serving to absorb recoil impact energy of the recoiling mass when the bolt moves from battery to recoil positions.

2. The assembly of claim 1 in combination with a firearm having a buffer engageable with the backplate damper upon installation of the conversion assembly into the firearm chamber, wherein the backplate damper is urged a predetermined distance forwardly of its rear limit positions by the firearm buffer when the bolt is in battery position for minimizing rebound of the bolt during its movements between battery and recoil positions.

3. The assembly of claim 1 wherein the backplate damper includes a lug receiving locating slot for locating and retaining the conversion assembly in operative position relative to the firearm receiver.

4. The assembly of claim 3 further including a modified conversion magazine having an upstanding lug, the conversion adaptor having a bottom surface with a lug receiving locating slot which cooperates with the magazine lug, upon mounting the magazine in the firearm receiver, for locating and retaining the conversion ssEmbly in operative position relative to the firearm receiver.

5. The assembly of claim 1 wherein the bolt is an elongated member having an axially extending firing pin passageway, a firing pin is received in the passageway for reciprocating movements between forward and rear positions, a hammer actuated striker is mounted in the bolt for movement between forward and rear operative limit positions, a return coil spring is concentrically received in the passageway about the firing pin for urging it toward its rear position and biasing the striker toward its rear limit position for hammer engagement, and a sleeve is received in the passageway surrounding the firing pin and having an annular front wall serving as a return spring seat.

6. The assembly of claim 1 wherein the bolt is an elongated member carrying a cartridge rim-engaging extractor and cartridge wall-engaging ejector assist member, the extractor and the ejector assist member each being supported on the bolt for pivotal movement toward and away from the major longitudinal axis of the bolt, spring means in the bolt normally biasing the extractor and the ejector assist member toward the central longitudinal axis of the bolt, the conversion adaptor having a rear face with a cartridge chamber extending axially forwardly therefrom, and first and second ramp surfaces formed in the adaptor and diverging from the rear face of the conversion adaptor radially outwardly of its chamber for camming the extractor and ejector assist member radially outwardly when the action spring moves the bolt into battery in engagement with the rear face of the conversion adaptor.

7. A firearm conversion assembly detachably insertable into a chamber of a firearm receiver upon removal of its standard bolt means for converting the firearm to fire ammunition of a caliber smaller than its standard caliber and comprising a conversion chamber adaptor insertable into the firearm chamber in fixed relation thereto, a bolt, a backplate damper, mounting means including a pair of guide rods threadably fixed to the adaptor and supporting the bolt and the backplate damper for reciprocable movement, the bolt being reciprocable between a forward battery position in engagement with the conversion adaptor and a rear recoil position, at least one of the guide rods establishing a rear limit position for the backplate dampler and cooperating with the backplate damper in establishing the rear recoil position of the bolt, an action spring mounted on one of the guide rods between the bolt and the backplate damper urging the bolt forwardly toward battery position and urging the backplate damper toward its rear limit position, the backplate damper being engageable with the bolt and serving to absorb recoil impact energy of the recoiling mass when the bolt moves from battery to recoil positions, the guide rods detachably securing the conversion assembly components in an integral unit for quick and easy installation and removal relative to the firearm receiver.

8. A firearm conversion assembly detachably insertable into a chamber of a firearm receiver upon removal of its standard bolt means for converting the firearm to fire ammunition of a caliber smaller than its standard caliber and comprising a conversion chamber adaptor insertable into the firearm chamber in fixed relation thereto, an elongated bolt including an axially extending firing pin passageway having concentric passageway portions with a rear maximum diameter portion, a forward reduced diameter portion and an interconnecting portion therebetween of intermediate diameter size, a firing pin in the passageway reciprocable between forward and rear positions, the firing pin having a radially enlarged end flange received in the maximum diameter passageway portion and a shank extending into the forward passageway portion and merging with said end flange with a smoothly contoured fillet radius, a hammer actuated striker received in the rear maximum diameter passageway portion of the bolt for movement between forward and rear operative limit positions, a return coil spring concentrically received in the passageway about the firing pin for urging it toward its rear position and biasing the striker toward its rear limit position for hammer engagement, a sleeve received in the passageway surrounding the firing pin shank and having an annular front wall serving as a return spring seat, the sleeve confining the return spring within the intermediate passageway portion between the front wall of the sleeve and an abutment formed at the juncture between the intermediate and forward passageway portions, mounting means mounting the bolt for reciprocable movement between a forward battery position in engagement with the conversion adaptor and a rear recoil position, a backplate damper supported by the mounting means in a position disposed rearwardly of the bolt, and an action spring between the bolt and the backplate damper urging the bolt forwardly toward battery position, the backplate damper being engageable with the bolt and serving to absorb recoil impact energy of the recoiling mass when the bolt moves from battery to recoil positions.