Title:
High velocity ammunition system and firearm
Kind Code:
A1


Abstract:
A round of high velocity ammunition contained within a modified chamber of a conventional firearm has a cartridge case, a sabot mounted within the forward-end of the case and a carrying projectile matching the caliber of the firearm for engaging rifling in the firearm bore, and a quantity of a propellant charge sufficient to impart a muzzle velocity in excess of 25,000 (ft./sec.) to the projectile. The cartridge case and the projectile cooperate with a rearwardly facing abutment surface of the chamber to confine the sabot which has an forwardly facing bearing surface coaxially surrounding a portion of the projectile and in abutting engagement with the abutment surface. When the round is fired substantially instantaneous dynamic forces generated by the gases of explosion propel the projectile from the chamber into and through the bore while simultaneously comprising the sabot to a fracture point. The fragmented sabot is entrained in the gases of explosion and escapes from the firearm through the muzzle end of the barrel.



Inventors:
Mochak, Richard J. (Russell, MA, US)
Application Number:
11/137840
Publication Date:
01/19/2006
Filing Date:
05/25/2005
Assignee:
Smith & Wesson Corp. (Springfield, MA, US)
Primary Class:
International Classes:
F42B14/06
View Patent Images:



Primary Examiner:
CLEMENT, MICHELLE RENEE
Attorney, Agent or Firm:
BALLARD SPAHR LLP (ATLANTA, GA, US)
Claims:
What is claimed is:

1. The combination comprising; a firearm, and a cartridge disposed in firing position within said firearm, said firearm having a generally cylindrical axially extending bore including a breech end and a forward or muzzle end, and a cylindrically stepped cartridge chamber in coaxial communication with said breech end, said chamber including a front portion having a diameter substantially equal to the diameter of said bore, a rear portion having a diameter substantially larger than the diameter of said front portion and a generally rearwardly facing annular abutment surface forming a transition between said front and rear portions for complimentary abutting engagement with a bearing surface on an associated cartridge received in a firing position within said chamber, said cartridge having a cylindrical case slideably received within said rear portion and including a mouth opening at its forward end and a base forming a closure for its rear end, a sabot received within said mouth and supported within said case, said sabot having a forwardly open projectile receiving bore an annular forwardly facing surface coaxially surrounding said projectile receiving bore and comprising said bearing surface, a projectile received and supported within said projectile receiving bore and extending for some distance into said forward portion, and a quantity of explosive propellant contained within said case rearward of said sabot for propelling said projectile out of said chamber and into and through said bore and for fracturing and fragmenting said sabot within said chamber and propelling the fragments of said sabot from said chamber into and through said bore and discharging said fragments at said muzzle end when said cartridge is fired.

2. The combination set forth in claim 1 wherein said abutment surface and said bearing surface comprise opposing radially disposed surfaces.

3. The combination set forth in claim 1 wherein said abutment surface comprises a generally conical rearwardly diverging surface centered on the axis of said chamber.

4. The combination set forth in claim 3 wherein said at least one bearing surface is defined by a conical surface of revolution centered on the axis of said cartridge.

5. The combination as set forth in claim 1 wherein said sabot is partially defined by a plurality of circumaxially spaced apart and axially forwardly projecting petals.

6. The combination set forth in claim 1 wherein said sabot has a plurality of distinct barring surfaces thereon.

7. The combination as set forth in claim 6 wherein said sabot is partially defined by a plurality of distinct axially forwardly extending petals and each of said petals defines in associated one of said distinct bearing surfaces.

8. The combination set forth in claim 1 wherein said projectile has a generally cylindrical rear portion received in press fit within said projectile receiving bore.

9. The combination set forth in claim 8 wherein said sabot is received and retained in press fit within said case.

10. The combination as set forth in claim 9 wherein said case is crimped radially inwardly at said mouth opening to further retain said sabot in said case.

11. The combination set forth in claim 1 wherein said projectile has an ogival forward portion forming a transition with a generally cylindrical trailing portion.

12. The combination set forth in claim 1 wherein said projectile receiving bore is a stepped bore including a rear portion, a front portion having a diameter larger than the diameter of said rear portion and a radially disposed and forwardly facing shoulder forming a transition between said front and rear portions.

13. The combination as set forth in claim 12 wherein said stepped bore comprises a blind bore and said sabot has a generally rearwardly facing end wall forming a closure for the rear end of said projectile receiving bore.

14. The combination as set forth in claim 13 wherein said rear wall has a generally radially disposed rear surface.

Description:

CROSS REFERENCE TO RELATED APPLICATION

This application is entitled to the benefit of and incorporates by reference essential subject matter disclosed in U.S. Provisional Patent Application No. 60/574,246, filed May 25, 2004.

FIELD OF THE INVENTION

This invention relates in general to high velocity firearms and associated high velocity ammunition and deals more specifically with improvements in hand guns, particularly revolvers and high velocity ammunition for such firearms.

BACKGROUND OF THE INVENTION

Bottleneck ammunition is well known in the firearm art and is usually used in rifles, particularly those of bolt-action type, and other long guns. A typical bottleneck ammunition cartridge includes an axially elongated cartridge case which has a cylindrical forward end portion within which a projectile or bullet is supported, a generally cylindrical rear end portion which has a base and a major diameter substantially greater than the diameter of the forward end portion, which carries the projectile. A neck-down portion disposed intermediate the front and rear portions of the cartridge case provide smooth transition there between. This bottleneck cartridge case configuration allows for the provision of a relatively large amount of a propellant charge to be contained within the rear portion of the case as is necessary for the attainment of a high muzzle velocity. The term “high velocity”, as hereinafter used, is intended to mean a muzzle velocity in excess of about 2,500 feet per second (ft./sec.).

Previous attempts to use bottleneck type cartridges with revolvers have proven generally unsuccessful. Such cartridges tend to expand when fired and drive the spent cartridge case in a rearward direction and toward the standing breech or bolster surface on the revolver frame at the immediate rear of the revolver cylinder. This condition may be attributed to some of the force generated by the gases of explosion in firing the cartridge being dissipated against the inner surfaces of the cylindrical and neck-down portions of the case, resulting in a net force vectoring the cartridge case in a rearward direction. Consequently, rotation of the revolver cylinder is likely to be inhibited if not precluded. It has also been found that if none of the cartridge cases are driven against the revolver frame with sufficient force to inhibit or preclude proper cylinder indexing rotation and or movement of the cylinder between open and closed positions relative to the revolver frame, extraction of the spent cases may be only marginally satisfactory if not totally unacceptable.

It is the general aim of the present invention to provide and improve ammunition system to allow for sufficient propellant charge or powder quantity to generate the energy necessary to achieve desired velocities while retaining the desired consistent functional characteristics of the firearm with which the ammunition is used.

It is a further aim of the present invention to provide improved handguns and particularly revolvers for effectively employing ammunition of the present invention while assuring consistent trouble free functionality of the action of the gun in which the cartridge is fired.

SUMMARY OF THE INVENTION

In accordance with the present invention, a firearm for use with a round of high velocity ammunition also embodying the invention and having a projectile matching the caliber of the firearm bore and for engaging rifling in the bore. The projectile is carried by a sabot mounted within a diametrically enlarged cartridge case containing a propellant charge capable of propelling the projectile from the firearm at a high muzzle velocity. Further, and in accordance with the invention, the firearm has a chamber configured and dimensioned to cooperate with the cartridge case and the projectile to confine the nonmetallic sabot so that it will be compressed to a point of fragmentation and fragmetized by the dynamic forces generated by expansion of the gases of explosion when a high velocity propellant charge contained within the diametrically enlarged cartridge case. When the firearm is discharged, dynamic forces generated by the substantially instantaneous expansion of the gases of explosion compress and fragmentize the sabot. The sabot fragments, entrained in the escaping gases of explosion, travel through the firearm bore and escape from the firearm at its muzzle end.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of a revolver embodying the present invention and utilizing the ammunition system of the present invention.

FIG. 2 is a fragmentary side elevational view of the revolver of FIG. 1 shown with the cylinder in open position.

FIG. 3 is a sectional view taken along the line 3-3 of FIG. 2.

FIG. 4 is an exploded perspective view of the revolver cylinder and shows the cylinder support yoke and the extractor mechanism.

FIG. 5 is a somewhat enlarged rear view of the revolver cylinder.

FIG. 6 is a somewhat enlarged rear elevational view of the extractor.

FIG. 7 is a somewhat enlarged schematic view illustrating the cylinder indexing mechanism.

FIG. 8 is a somewhat enlarged axial sectional view through a cartridge embodying the ammunition system of the present invention.

FIG. 9 is a sectional view taken along the line 9-9 of FIG. 8.

FIG. 10 is a sectional view taken along the line 10-10 of FIG. 8.

FIG. 11 is a perspective view of the sabot shown in FIGS. 8-10.

FIG. 12 is an axial sectional view through a revolver cylinder 12 chambered in accordance with the invention and shown with cartridges embodying the present invention in the chargeholes of the cylinder.

FIG. 13 is similar to FIG. 8, but shows another cartridge embodying the ammunition system of the present invention.

FIG. 14 is an axial sectional view taken along the line 14-14 of FIG. 13.

FIG. 15 is a sectional view taken along the line 15-15 of FIG. 13.

FIG. 16 is a perspective view of the sabot shown in FIGS. 13-15.

FIG. 17 is an axial sectional view through yet another cartridge embodying the ammunition system of the present invention.

FIG. 18 is a sectional view taken along the line 18-18 of FIG. 17.

FIG. 19 is a sectional view taken along the line 19-19 of FIG. 17.

FIG. 20 shows another revolver cylinder for use with the revolver of FIG. 1 to fire cartridges shown in FIGS. 17-19.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Turning now to the drawings, a high velocity firearm or revolver embodying the present invention and particularly adapted to fire high velocity ammunition embodying the invention is shown in FIG. 1 and indicated generally by the reference numeral 10. The illustrated firearm 10 is a modified Model 500 Smith & Wesson Revolver, manufactured by Smith & Wesson Corp., Springfield Mass., assignee of the present invention, and includes a frame 12 and an axially elongated barrel 14 mounted in fixed position and projecting in and axially forward direction from the frame. The barrel defines a rifled bore, 16 which extends axially through it from a breech or rear end to a forward or muzzle end. The revolver 10 further include a rotary cylinder 18, which is supported for indexable rotation relative to the frame has a circumaxially series of equangularly spaced apart chargeholes 20,20 extending therethrough. The chargeholes are chambered in accordance with the present invention to receive high velocity ammunition embodying the present invention, as will be hereinafter further discussed.

Referring now particularly to FIGS. 2 and 3. The cylinder 18, shown somewhat schematically, is supported on the frame 12 by a yoke 22 to pivot relative to the frame and about an axis 24 between a closed or firing position wherein the cylinder is disposed within an opening 25 defined by the frame and shown in FIG. 1, and an open position, shown in FIGS. 2 and 3, wherein the cylinder is disposed generally adjacent the left side of the frame 12. In the cylinder open position extracted spent cartridges may be dumped from the cylinder to permit cylinder reloading. A cylinder release mechanism (not shown) normally biased to a cylinder retaining position secures the cylinder 18 in closed position within the frame opening 25, as previously discussed. A thumb piece 26 located on the left side of the frame 12 rearward of the cylinder 18 is operable to release the cylinder from closed position and allow it to be rotated out of the frame opening 25 and to open position. Further disclosure of a cylinder supporting yoke and the manner in which a revolver cylinder may be supported on a revolver frame for pivotal movement between open and closed positions is found in U.S. Pat. No. 1,181,417 to Wesson, which is hereby adopted by reference as part of the present disclosure.

The revolver 10 has an extractor of conventional type for removing spent cartridge cases from the charge holes or chambers 20,20 of the revolver cylinder 18 as shown in FIG. 4. The extractor, indicated generally at 28 comprises a star or extractor plate 30 mounted in a recess in the rear surface of the cylinder 18. The extractor plate 30 is mounted on the rear end of a tubular stem 32 and has a plurality of radially extending arms 34,34 equangularly spaced about the axis of the stem 32 and defining between each adjacent pair of arms a parti-cylindrical surface which conforms with the inner-cylindrical surface portion of one of the cartridge chambers 20 formed in the revolver cylinder 18. The extractor plate 30 also includes, on its rear surface, a rearwardly projecting ring or annulus 29 on which there are formed a plurality of ratchets (not shown), equal in number to the chambers 20,20, for a purpose which will be hereinafter further explained. The depth of the recess within which the extractor plate 30 is received is substantially equal to the thickness of the extractor plate, so that the rearwardly facing surfaces of the extractor plate and the cylinder 18 are disposed within a substantially common radial plane when the cylinder 18 is retained in closed or firing position. In the latter position the curved inner edges on the extractor plate, defined by the arms 34,34 are disposed forward of a rim on each of the cartridge cases disposed within the cylinder 18. After the cartridges in the cylinder have been fired, the cylinder retaining mechanism has been operated, and the cylinder has been moved out of the frame opening 25 and to it's open position, a rearward thrust on the extractor or stem rod will cause the spent cartridge, cartridges to be pushed rearwardly and out of their respectively associated charge holes for dumping to permit reloading.

A more complete disclosure of a presently preferred extractor mechanism for use in practicing the present invention is found in my earlier U.S. Pat. No. 5,218,148, which is hereby adopted by reference as part of this disclosure.

The illustrated revolver, which embodies the present invention, also includes a conventional cylinder indexing mechanism shown somewhat schematically in FIG. 7 and indicated generally by the reference numeral 36. The indexing mechanism includes a trigger 38 for operating a firing mechanism (not shown). The trigger 38 is pivotally supported on the frame 12 by a pivot pin 40. A hand 42 pivotally connected to the trigger is configured to cooperate with the ratchet, one of the cylinder chambers 20,20 into coaxial alignment with the bore each time the trigger is operated. As each of the chambers 20,20 is indexed into alignment with the barrel a latch 42 associated with the trigger mechanism moves into latching engagement within an associated keeper opening in the cylinder to secure the cylinder in its position during the firing cycle. A more complete disclosure of such an indexing mechanism is found in U.S. Pat. No. 6,571,502 to Mikuta, assigned to the assignee of the present invention and hereby adopted by reference as part of the present disclosure.

It is anticipated that the ammunition system of the present invention will prove suitable for use with a wide variety of types of firearms. A revolver having operational characteristics which particularly suitable for use with ammunition in accordance with the present invention having been hereinbefore described ammunition embodying the present invention will now be considered and with particular reference to the inventive concepts of the firearm chamber within which it is received.

Referring now particularly to FIGS. 8-10 a cartridge or round of ammunition embodying the ammunition to system of the present invention is indicated generally by the reference numeral 50. The illustrated cartridge 50 essentially comprises a case 52 a projectile or bullet 54 a sabot 56 for positioning and supporting the projectile within the case and a predetermined quantity of a propellant or outer charge suitable for imparting to the projectile a muzzle velocity in excess of 2,500 (ft./sec.).

The invention is preferably practiced with metal, rimed cartridges of centerfire type the case being preferably fabricated from brass. The case may be characterized as an axially elongated generally cylindrical thin walled shell which includes a radially disposed base 60 at its rear end percussion cap or primer is mounted centrally within a rearwardly open recess in the base wall and communicates with the interior of the case through a central bore opening 62. The major diameter of the case ranges from about 0.4 in. to about 0.5 in.

The invention maybe practiced with projectiles of various kinds. The presently preferred projectile 54 has an ogival head portion indicated at 64 which forms a transition with a generally cylindrical trailing portion 66 having an axial length approximately equal to the length of the end portion 64. In accordance with the invention, the projectile 54 is matched to the caliber of the firearm with which it is to be used and it is intended that the projectile engage the bore rifling in a conventional manner. Preferably, the present projectile has a major diameter ranging from about 0.264 in. to about 0.308 in.

A sabot is conventionally used as a carrier for a sub-caliber projectile engages the bore or rifling of a firearm from which the projectile is fixed. However, in accordance with the present invention, the only function of the sabot 56 is to position and support the relatively small diameter projectile in coaxial alignment with the substantially larger diameter case 52. The present sabot, is preferably molded otherwise formed from a somewhat resilient lightweight non metalic plastic material. It has an axially elongated generally cylindrical body with a coaxial stepped bore 68. The bore 68 has a generally cylindrical front-end portion 70 a rear-end portion 72 of somewhat smaller diameter and a radially disposed annular shoulder 74 which forms a transitional surface between the front portion and the dramatically reduced rear portions of the sabot bore 68. Generally radially disposed annular surfaces 76 and 78 coaxially surround the front and rear bore portions 70 and 72, substantially as shown. The axial length of the front portion 70 is substantially equal to the axial length of the projectile trailing portion 66 which is received in press fit within the front portion 70 of the sabot bore whereby the projectile 54 is located relative to sabot 56. The sabot 56 is, in turn and with the rear surface of the projectile in engagement with the shoulder 74 of the sabot received within the case 52 through the mouth thereof and is disposed in press fit engagement with the case. The forward end portion of the case which defines the mouth thereof is crimped into engagement with the sabot proximate the frontal bearing surface 76 of the sabot. Thus, the latter radially disposed frontal surface is exposed at the mouth of the cartridge for complementary abutting engagement with the transitional abutment surface of the chamber 20.

Referring now to FIG. 12 the cartridge 50 is shown in its firing position within an associated chamber 20 of the revolver cylinder 18. In accordance with the invention the chamber 20 has a cylindrical stepped bore extending through it. The bore 20 has a cylindrical forward end portion 80 sized to receive the projectile 54 therethrough and provide smooth transition into the barrel bore. The substantially larger rear portion of the chamber 20, indicated by the numeral 82 is sized to receive the cartridge case in a conventional manner. A generally radially disposed and rearwardly facing abutment surface 84 forms a transition between the forward and rear portions of the chamber 20.

When the cartridge 50 is loaded in an associated cylinder chamber 20 the radial bearing surface at the forward-end of the sabot, is disposed in abutting engagement with the rearwardly facing annular abutment surface of the chamber.

When the round 50 is fired the substantially instantaneous increase in pressure generates dynamic forces acting upon the exposed rear surfaces of the projectile 54 and the sabot 56 sufficient to impart to the projectile the desired velocity while simultaneously compressing the sabot to a point of fracture at which point it acquires brittle characteristics so that the dynamic forces acting upon it cause it to fracture, and fragment. The resulting sabot fragments become entrained in the gases of explosion leaving the barrel through the muzzle of the firearm. Experimental firing has indicated that all of the relatively light sabot material leaves the barrel through the muzzle. However, should any sabot material remaining in the spent cartridge it will be removed from the chamber with the extracted spent cartridges. Initial indications are that sabot residue will not be a problem.

Referring now to FIG. 13 of the drawings another round of ammunition embodying the ammunition system of the present invention is shown. And is indicated generally by the reference numeral 50a. The round 50a is similar, in most respect, to the round 50 previously described and parts of the round 50a which are substantially identical to parts of the previously describes round 50 bear the same reference numerals and a letter “a” suffix and will not be hereinafter further described. Like the round of ammunition 50, the round 50a includes a cartridge case, 52a projectile 54a and a propellant charge 58a. However, the sabot used in the round 50a has a circumaxally spaced apart series of axially forwardly extending pedal 88,88. The number of pedals provided may vary, however, the illustrated sabot has four (4) such pedals defined by an equangularly spaced apart series of axially rearwardly extending slots 90,90, substantially as shown. The forwardly facing surfaces of the pedals comprise surfaces which are disposed in generally abutting engagement with a reawardly facing annular abutment surface of the modified chamber 20. The provision of pedals on an otherwise generally cylindrical sabot alter the projectile holding characteristics of the sabot to provide faster release of its associated projectile, where desired.

Yet another cartridge or round of ammunition embodying the present ammunition system is shown in FIGS. 17-19 and indicated generally by the reference numeral 50c. The illustrated round 50 differs from the previously described round 50b both in the construction and arrangement of its sabot and in the length of its cartridge case 52c. Specifically, the sabot 56c has a plurality of circumaxially spaced apart axially forwardly extending petals 88c, 88c, six shown. The petals extend for some distance beyond the mouth of the cartridge case. Each petal 88c has a generally forwardly facing bearing surface 92. The bearing surfaces 92, 92 are defined by a rearwardly diverging conical surface of revolution centered on the central axis of the sabot. These surfaces are disposed in abutting engagement with complimentary surfaces on the transitional surface of the chamber of the firearm, as previously discussed. Since the overall length of the cartridge 52c is dictated by the axial length of an associated revolver cylinder 18c. The case 52c is shortened to allow for the bearing surfaces on the sabot which project forwardly beyond the mouth of the cartridge at substantially as shown in FIG. 17.