US3845581A - Firearms - Google Patents

Abstract

A firearm is provided which has a barrel including a bore having helical grooves and lands between said grooves, and a detachable chamber comprising a tubular body having an inner diameter equal to the diameter of the bore across the lands defined by the helical grooves, one end of the tubular body abuting against the base of the barrel, and the other end having an annular recess adapted to receive and retain a peripheral flange at the rear end of a projectile adapted to be fired from the firearm.

Description

United States Patent [1 1 lnfantino Nov. 5, 1974 FIREARMS 1,191,357 7/1916 Snyder 42/78 1751 Inventor: Osvaldo Csar famine, 3332? $1312 $3323.;';;;1::3"":::::"""iji'z'zffl Aires, Argentina v [73] Assignee: Direceion General de lnvestigacion y P i E i B j in A, Borchcit DeSalTOllO Mini5teli0 de Assistant Examiner-C. T. Jordan Defensa kepubhtca Argentina, Attorney, Agent, or FirmLerner, David. Littenberg Buenos Aires, Argentina & Sam el {22] Filed: July 6, 1972 Appl. No.: 269,325

Foreign Application Priority Data July 6, 1971 Argentina 236638 US. Cl. 42/76 R, 42/78 Int. Cl. F4lc 21/12 Field of Search 42/76 R, 76 A, 77, 78

References Cited UNITED STATES PATENTS ll/l885 Wheeler 42/77 [57] ABSTRACT 4 Claims, 4 Drawing Figures FIREARMS This invention refers to a detachable chamber for a firearm having a barrel with a helically grooved bore, and more particularly, to a chamber for firing the ballistic, self-propelled projectile described and claimed in co-pending patent application filed on Oct. 18, 1971 No. 189,905.

The invention is also concerned with a firearm including said chamber.

The projectile described in the above-mentioned patent application, is capable of being totally expelled through the bore of the firearm without leaving any residue therein. Said projectile comprises a body of substantially cylindro-ogival shape having a propellant cavity therein, priming means in said propellant cavity, and an outer, peripheral flange at the rear, terminal end of said body and integral therewith. The maximum outer diameter of the body is equal to, or slightly less than the diameter of said bore across the lands defined between the helical grooves; and the outer diameter of said rear peripheral flange is larger than the diameter of the bore across said lands. When the projectile is fired and impelled through the bore, the rear peripheral flange is deformed or extruded by the walls of the chamber and the projectile body expands under the pressure of firing and engages the lands in the bore, thus causing the projectile to spin while it travels through the bore.

The firearm chamber according to the invention is detachably mounted in the breech of the firearm and comprises a tubular body having an inner diameter equal to the diameter of the bore across the lands defined by the helical grooves. One end of the tubular body abuts against the base of the barrel, and the other end has an annular recess adapted to receive and retain the peripheral flange at the rear end of the above mentioned projectile.

The firearm chamber of the invention differs from known chambers in that its inner diameter is equal to the diameter of the bore in the barrel across the lands defined by the helical grooves and therefore, it can be used only for firing a projectile having an outer diameter equal or slightly less than the diameter of the bore across the lands. Conventional amunnition, i.e., of the type having a case and a bullet fitted at the mouth of the case, cannot be fired from a chamber according to the invention, because if the case fits the chamber, the bullet would be undersized with respect to the bore. Consequently gas leakage would occur since the required compression could not be attained and, furthermore, it would not be possible to obtain gyroscopic stability of the trajectory of the projectile.

The fact that the chamber is detachably mounted in the breech of the firearm and independent from the barrel, permits manufacturing it from a metal having different characteristics than the metal forming other parts of the firearm, and to replace the chamber or the barrel if one of them should become worn or damaged.

In addition, a detachable chamber simplifies considerably the operation of making the rifling or helical grooves in the barrel bore, since the rifling could be made in a continuous length of tubing which can then be severed to form individual barrels.

Furthermore, the detachable chamber, permits independent machining, finishing and heat treating of the chamber and the barrel, which facilitates handling and obtaining high dimensional accuracy.

The invention will now be described with reference to the accompanying drawings in which:

FIG. 1 is an elevation view of a projectile adapted to be used with a firearm including a chamber according to the invention.

FIG. 2 is a longitudinal section of a firearm chamber according to the invention.

FIG. 3 is a plan view of the chamber.

FIG. 4 is a longitudinal section, somewhat schematic, of a firearm indicating the location and arrangement of the firearm chamber. a

The firearm chamber of the invention is designed to fire self propelled ballistic projectile such as shown in FIG. 1. This projectile comprises a body 1, of substantially cylindro-ogival shape, having an outer, peripheral flange 2 at the rear, terminal end of the body.

The flange 2 is formed integrally with the projectile body and extends substantially at right angles with the longitudinal axis of the projectile. The diameter and thickness of the flange 2 depend on the calibre of th projectile.

With reference to FIG. 4, the firearm shown therein comprises a bolt housing 3 and a barrel 4. The barrel bore has a series of parallel grooves 5 which spiral from the base to the muzzle end of the barrel and define land portions 6 therebetween.

The maximum outer diameter of the projectile body 1 is equal to or slightly less than the diameter of the bore across the lands 6.

As it can be best seen in FIGS. 2 and 3, the firearm chamber of the invention, comprises a tubular body 7, having an inner diameter equal to the diameter of the bore of the barrel across the lands defined by the helical grooves 5. The forward end 8 of the chamber is adapted to abut against the base of the barrel, and the rear end 9, has an annular recess 10 adapted to receive and retain the peripheral flange 2 at the rear end of the projectile.

The recess 10 has an annular surface 10 perpendicular to the longitudinal axis of the chamber, and a cylindrical wall 10'', coaxial with the chamber. The diameter and depth of the recess 10 corresponds with the diameter and thickness of the projectile flange.

The chamber is housed in a bore 11 provided in the bolt housing 3 of the firearm and rests on shoulder portions 12. The barrel has a threaded portion 4' which screws into the bolt housing 3 and is secured in place by a locking nut 13. Thus, the chamber is retained between the barrel 4 and the shoulder portions 12.

The rear end of the chamber is closed by a cylindrical lock 14 having a percussion pin 14'.

A projectile placed in the chamber, with its peripheral flange resting in the recess 10, is fired by percussion of the priming means of the projectile (not shown) with the percussion pin '14. Upon firing, the projectile is impelled through the chamber and its flange is deformed or extruded by the inner walls of the chamber.

. Almost simultaneously, the projectile body expands slightly under the pressure of firing and engages the lands in the bore thus causing the projectile to spin while it travels through the bore.

As explained in the aforementioned copending patent application, the rear flange 2 acts as a stop for the projectile in the chamber before the projectile is fired, and also as a sealing ring while the projectile travels through the bore. As indicated, the projectile is totally expelled from the firearm without leaving any residue therein.

It will be obvious to those expert in the art that the size of the chamber, the thickness of the walls, and the depth and diameter of the recess 10, will depend on the calibre of the firearm.

While the invention has been described in connection with a specific embodiement thereof, it is to be understood that this is by way of example and not by way of limitation; and the scope of the appended claims should be construed as broadly as the prior art will permlt.

What is claimed is:

l. A firearm comprising a barrel including a bore having helical grooves and lands between said grooves, and a detachable chamber comprising a tubular body having an inner diameter equal to the diameter of said bore across the lands defined by the helical grooves. one end of said tubular body abutting against the base of said barrel, and the other end having an annular recess adapted to receive and retain a peripheral flange at the rear end of a projectile adapted to be fired from said firearm.

2. A firearm chamber as claimed in claim 1 wherein said annular recess has an annular surface substantially perpendicular to the longitudinal axis of the chamber, and a cylindrical wall substantially coaxial with the chamber.

3. In combination, a firearm barrel having a bore, said bore including helical grooves and lands between said grooves; a chamber comprising a tubular body having an inner diameter equal to the diameter of said bore across the lands defined by the helical grooves, one end of said chamber abutting againstthe base of said barrel, and the other end having an annular recess; and a self-propelled ballistic projectile. comprising a body of substantially cylindro-ogival shape and an outer peripheral flange at the rear terminal end of said projectile body; the annular recess of said chamber being adapted to receive the peripheral flange of said projectile; the outer diameter of the projectile body being at most equal to the inner diameter of said chamher.

4. The combination in accordance with claim 3 wherein the outer diameter of the projectile body is slightly less than the inner diameter of said chamber.

Claims (4)

1. A firearm comprising a barrel including a bore having helical grooves and lands between said grooves, and a detachable chamber comprising a tubular body having an inner diameter equal to the diameter of said bore across the lands defined by the helical grooves, one end of said tubular body abutting against the base of said barrel, and the other end having an annular recess adapted to receive and retain a peripheral flange at the rear end of a projectile adapted to be fired from said firearm.

2. A firearm chamber as claimed in claim 1 wherein said annular recess has an annular surface substantially perpendicular to the longitudinal axis of the chamber, and a cylindrical wall substantially coaxial with the chamber.

3. In combination, a firearm barrel having a bore, said bore including helical grooves and lands between said grooves; a chamber comprising a tubular body having an inner diameter equal to the diameter of said bore across the lands defined by the helical grooves, one end of said chamber abutting against the base of said barrel, and the other end having an annular recess; and a self-propelled ballistic projectile, comprising a body of substantially cylindro-ogival shape and an outer peripheral flange at the rear terminal end of said projectile body; the annular recess of said chamber being adapted to receive the peripheral flange of said projectile; the outer diameter of the projectile body being at most equal to the inner diameter of said chamber.

4. The combination in accordance with claim 3 wherein the outer diameter of the projectile body is slightly less than the inner diameter of said chamber.

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