Chamber adaptor incorporated into a modified action assembly for permitting substitution of a first manufacturer specified cartridge for a second substitute cartridge   

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of U.S. Provisional Application 61/362,053 filed Jul. 7, 2010.

FIELD OF THE INVENTION

The present invention is directed to a modified chamber adaptor incorporated into a substitute firearm action assembly. More specifically, the present invention discloses a uniquely configured chamber adaptor for converting, in one non-limiting application, from 5.7 mm×28 mm center fire cartridges to less expensive and approximately diameter dimensioned 0.22 lr (inch) rimfire cartridges.

BACKGROUND OF THE INVENTION

Center fire cartridges are well known in use with various firearms. A disadvantage of using such cartridges such as in particular for target practice and the like is the associated cost in comparison to similar caliber rimfire cartridges, the latter often being significantly less expensive. In one known instance, 5.7×28 centerfire ammunition is employed in such as AR15/M16 and FN PS90 firearms, however no suitable adaptor is available for employing in the firearm action assembly for accepting significantly less expensive 0.22 rimfire cartridges.

SUMMARY

The present invention discloses a retrofit chamber adaptor associated with a substitute action assembly incorporated into a firearm for permitting the substitution of an original designated cartridge for a substitute cartridge. An elongated body is incorporated into a barrel accessible location of the firearm and supporting a bolt in reciprocating fashion. The chamber adaptor is mounted to forward end of the body in communication with the reciprocating bolt and exhibits a modified diameter aperture extending therethrough and corresponding to an incremental modification in diameter associated with the substitute cartridge.

Additional features include a receiver plate incorporated into the body and exhibiting a generally lengthwise extending notched or keyed interior established between generally parallel extending sides with identified and interiorly notched locations for seating in reciprocating fashion therebetween the reciprocating bolt. A further variation of the adaptor exhibits a dual rail configuration to which is reciprocally mounted the bolt and from which in turn forwardly projects a firing pin. In one preferred but non-limiting application, the chamber adaptor permits substitution of a 0.22 LR rimfire cartridge in lieu of a normally designated 5.7×28 mm center fire cartridge.

BRIEF DESCRIPTION OF THE DRAWINGS

Reference will now be made to the attached drawings, when read in combination with the following detailed description, wherein like reference numerals refer to like parts throughout the several views, and in which:

FIGS. 1A and 1B are prior art illustrations of both center fire 5.7×28 mm and 0.22 long rifle rim cartridges;

FIG. 2 is an illustration of a first version of a cartridge chamber adaptor for use with such as AR15 style rifles;

FIG. 3 is an illustration of another version of cartridge chamber adaptor for use with a Belgian FN P90 and PS90 personal defense weapons;

FIG. 4 is an illustration of the bolt carrier and action/recoil assembly associated with an AR-15 style assault rifle;

FIG. 5 is an illustration of a corresponding bolt carrier and recoil assembly associated with an FN P90/PS90 firearm; and

FIG. 6 is a diagrammatic illustration in cutaway of a chamber adaptor incorporated into a substitute action assembly associated with a P90/PS90 and further depicting the firing pin associated with the bolt in contact with a rimfire location of the substitute 0.22 LR cartridge.

DETAILED DESCRIPTION

The present invention is directed to a uniquely configured chamber adaptor incorporated into a substitute firearm action assembly. More specifically, the present invention discloses a chamber adaptor for converting, in one non-limiting application, from 5.7 mm×28 mm center fire (see at 2 in FIG. 1A) to less expensive 0.22 lr (inch) rimfire (see at 4 in FIG. 1B) ammunition.

In operation, rim fire ammunition (as opposed to center fire ammunition in which the firing pin strikes a primer cap at the center of a base of the cartridge), includes a widened base rim which is essentially a widened percussion cap containing the desired priming compound, while the associated cartridge case itself contains the propellant powder and projectile (bullet). By virtue of this construction, rim fire ammunition can be produced relatively less expensively than center fire cartridges, reinforcing the value of a suitably constructed chamber adaptor associated with a given weapon design, permitting substitution of lesser expensive cartridges.

Referring also to each of FIGS. 4 and 5, assembled views are shown of respective bolt carrier and recoil assemblies incorporating a specifically constructed chamber adapter (further respectively illustrated in FIGS. 2 and 3), for use with either an AR-15 assault type rifle (FIGS. 2 and 4) or an FN P90/PS90 action device (FIG. 3 and FIG. 5). It should be noted that the action assemblies shown in FIGS. 4 and 5 includes resized and substitute components associated with the receiver plate with inner notched and supporting side rails, reciprocally mounted bolt and forwardly positioned chamber adaptor, these substituting for original action assemblies (not shown) which are provided with the originally manufactured firearm.

Referring first to FIG. 4, in combination with the chamber adaptor separately depicted in FIG. 2, an adaptor bolt subassembly configured for an AR-15 style rifle is generally shown at 10 and exhibits generally elongated body in the form of a receiver plate at 12 and exhibits a generally lengthwise extending notched or keyed interior, established between generally parallel extending sides 14 and 16 with identified and interiorly notched locations (hidden from view) for seating a reciprocating bolt 18 (such as but not limited to a rim fire style bolt).

Forward projecting ends of the sides 14 and 16 extending beyond the forward displaced position of the bolt 18 define further end tabs for fixedly seating a chamber adaptor 20 with resized interior aperture 21 for accepting the resized 0.22 LR cartridge (and as also individually shown in FIG. 2). Additional features associated with the chamber adaptor include a series of grooves (one of which is illustrated at 23) associated with the main body of the chamber adaptor for facilitating non-rotating seating of the action assembly within the upper receiver barrel (not shown) associated with the AR-15 type firearm. Also depicted at 25 is an angled side groove to facilitate cartridge extraction associated with the exiting shell and bolt reciprocation features of the AR-15 type firearm.

As is again shown in FIG. 4, the forward open ends of the sides 14 and 16 are suitably configured (or notched) in order to fixedly support the chamber insert 20. The notched interior defined between the sides 14 and 16 is configured for seating the bolt 18 in a specified reciprocating range between a forward and bias directed end (in contact with the chamber adaptor 20) as shown, and a rearward counter-bias direction approximate a base interconnecting surface 22 (again FIG. 4) of the notched interior.

The configuration of the of a receiver plate at 12 and exhibits a generally lengthwise extending notched or keyed interior, established between generally parallel extending sides 14 and 16 with identified and interiorly notched locations (hidden from view) for seating a reciprocating bolt 18 (such as but not limited to a rim fire style bolt). A rearward projecting support sleeve 24 includes an open interior for receiving and seating an opposing guide rod 26 (about which is illustrated seated a biasing coil spring), the rod 26 associated with a further mounting location (see end disk 28) of the receiver plate 12 and in order to maintain in assembled fashion the adaptor bolt subassembly

Specifically, and referring to FIG. 5 (in combination with the individual illustration of chamber adaptor in FIG. 3), in combination an illustration is again generally shown at 30 of a corresponding bolt carrier and recoil assembly associated with an FN P90/PS90 (FN Herstal) firearm. Unlike the AR-15 type action assembly 10 which integrates within a separate upper action receiver, the bolt carrier and recoil assembly 30 for use in the Belgian FN Herstal P90/PS90 is configured in a bullpup design in which both the action 30 and top loading magazine (not shown) are located behind the trigger and alongside the shooter\'s face, such that there is no wasted space for the buttstock, as in conventional designs. This permits a shorter firearm length for the same barrel length, saving weight and increasing maneuverability in confined spaces.

Additional features of the P90/PS90 variants include the pistol grip with a thumbhole and oversized trigger guard acting as the forward grip, a handstop incorporated into the weapon\'s stock preventing the user from accidentally reaching out in front of the barrel during firing. The P90 is a modular firearm and consists of sixty-nine parts that disassemble into four main groups, including 1) the barrel with integrated sight assembly, 2) the receiver with return mechanism, 3) the stock body with trigger and firing mechanism and 4) the magazine. As is also known, the P90 makes extensive use of polymers and lightweight alloys to reduce both the weight and the cost of the weapon.

Referring again to FIG. 5, the assembly 30 defines an alternately configured elongate body which includes a dual rail 32 and 34 configuration to which is reciprocally mounted a bolt block 36 from which in turn forwardly projects a firing pin 38. The block 36 is illustrated in an intermediate position between a rear end and a forward end which engages a reconfigured chamber adaptor 40 (also FIG. 3). Although not shown, a suitable biasing aspect incorporated into the action assembly 30 (provided by such as a spring or the like) provides proper recoil action of the bolt 36.

The adaptor 40 (referring to FIG. 3) includes a generally widened block shape with a pair of apertures 42 and 44 defined therethrough for seating over the rails 32 and 34. A central aperture 46 exhibits a likewise resized profile (in comparison to that shown at 21 in the AR-15 type chamber adaptor of FIG. 2) and for accepting substitution 0.22 LR (inch) rimfire cartridges for standard issue 5.7 mm×28 mm centerfire cartridges and further given the relatively minimal disparity in diameter between the cartridges. Otherwise, and beyond the disclosure provided herein, the features associated with the FN P90/PS90 firearms are known in the art and do not require further elaboration.

Finally, FIG. 6 illustrates a diagrammatic illustration in cutaway of the substitute action assembly such as employed with a P90/PS90 type firearm. Further depicted in the cutaway view is a spring loaded firing pin, at 48, which is mounted within the bolt block 36 and in order to be biased forwardly into contact with a rimfire location of the substitute 0.22 LR cartridge 4. Also shown is a bottom located ejector mechanism 50 and which, in cooperation with the firing pin 48, facilitates ejection of the spent 0.22 LR rimfire casing 4 prior to cyclical reloading as per the gas recoil and reload particulars associated with a PN P90 type firearm.

Having described my invention, other and additional preferred embodiments will become apparent to those skilled in the art to which it pertains, such as providing additional configured chamber adaptors (for use in any suitable weapon and for substituting between any types of cartridges not limited to those described herein) and without deviating from the scope of the appended claims.