CA2576496A1

CA2576496A1 - Reloadable subsonic rifle cartridge

Info

Publication number: CA2576496A1
Application number: CA 2576496
Authority: CA
Inventors: Merv Byron
Original assignee: Individual
Current assignee: Individual
Priority date: 2007-01-25
Filing date: 2007-01-25
Publication date: 2008-07-25
Also published as: WO2008090505A3; WO2008090505A2

Abstract

This invention is designed to create a reloadable subsonic rifle cartridge casing. It utilizes a unique method of reducing the cavity within a rifle cartridge to restrict the powder capacity and allow for the efficient powder ignition and allow the projectile to travel at subsonic velocities, traveling below 1086 feet per second at sea level. This cartridge design will allow reloadable subsonic rifle cartridge cases to be manufactured in any conceivable rifle caliber.
The cartridge can be used in any rifle action designed for that particular caliber without any modification to the firearm. It further allows multiple cartridges to be placed within any standard rifle magazine and to function and feed correctly into the rifle chamber. The cartridge will also produce sufficient pressures to allow the reliable functioning of a blow back semi automatic action.
The cartridge will allow the user to reload the casing with any variety of bullet weights and designs suitable for that caliber. It will also allow the reloading of that cartridge in the field with a minimal amount of reloading equipment and required skill level.

Description

RELOADABLE SUBSONIC RIFLE CARTRIDGE

This invention relates to a reloadable rifle cartridge case that is able to propel any standard rifle bullet for a particular caliber at subsonic speeds during free flight at less than the speed of sound.
BACKGROUND OF INVENTION

Under most normal conditions all rifle cartridges have been designed to propel a projectile or bullet from a fired weapon, particularly a rifle, during free flight at speeds exceeding the speed of sound or supersonic which is greater than approximately 1086 ft/sec. at sea level under standard conditions of temperature and pressure. The faster a projectile travels, the flatter is its trajectory on route to its target. Also the faster a projectile travels, the more the effects of lateral wind deflection are reduced, maintaining greater accuracy to the intended target. Therefore, to obtain long range accuracy, it has been the common practice to load rifle cases with the maximum amount of propellant within permissible pressure limits to safely fire the projectile.

When a projectile travels at supersonic speeds it generates an audible sound called a sonic boom during its free flight to the target. This sonic boom can be an undesirable characteristic of supersonic projectiles as they announce the location of the weapon, which has fired the round. During a variety of hunting situations, keeping the firing location of the rifle hidden is desirable, as it would also be during certain Military or Police operations in heavily populated areas.
Customized sound suppressors fitted onto the muzzle end of the rifle can be utilized to reduce the sound of the muzzle blast while firing but they will not circumvent the sound of the supersonic boom as the projectile breaks the sound barrier. The only method of reducing the effect of the sonic boom is to propel the projectile at subsonic speeds so that during free flight it does not exceed the speed of sound.

The only method of accomplishing this end result is to reduce the amount of propellant used within the case. There have been a wide variety of attempts to accomplish this process. They have ranged from utilizing a small amount of fast burning pistol powder as the charge, which has had some very dangerous results, to using very slow burning cannon powder which is not readily available to the handloader in a wide variety of calibers. There have also been attempts to reduce the exterior size of the cases, thus reducing the interior capacity, but is impossible for the reloader to accomplish.
Additional attempts have been to restrict the available space inside the case by inserting such things as, paper discs, foam wadding, and pliable expanding cylinder tubes that take up excess space. All of these latter methods have their own inherent problems, but most importantly, none are available to the handloader to duplicate.

The proposal is to create a reloadable rifle cartridge case which will look and perform within the corresponding rifle action identical to that of any standard commercially produced rifle cartridge but have its internal capacity to contain propellant reduced so that the projectile can be safely fired, and will travel at subsonic speeds.

Previous attempts to create subsonic rounds have entailed a variety of manufacturing methods. The problems encountered in attempting to create a safe subsonic cartridge, have centered around the quantity of gunpowder used within the case as compared to the available space existing within the case. Under loading a rifle case with insufficient propellant will result in inadequate pressures being developed to a seal between the neck of the case and the rifle chamber, thus allowing the gas produced by the rapid burning of the propellant to escape around the casing back into the action, resulting in insufficient pressure to propel the projectile out of the rifle barrel, creating an extremely dangerous situation.

Other problems encountered have included the inconsistent burning rate of the propellant within the cartridge caused by the movement of the powder within the case as the round is tipped up or down during the aiming of the rifle at targets on uneven terrain. This creates inconsistent pressures, though adequate to expel the projectile from the rifle barrel, the inconsistent pressures result in very inaccurate rounds, and difficulty in hitting the desired target.

It has also been the practice to use fast-burning powders, e.g. pistol powders to create sufficient pressures to fire a projectile in a subsonic manner. However these powders exacerbate the problem of inconsistent propulsion of a projectile from the weapon by reason of the rapid build up of pressure within the case and the rapid fall-off of the pressure once the projectile leaves the case. As a consequence, the attempts to manufacture subsonic rifle ammunition utilizing fast burning pistol powder, fails to provide the energy needed to operate the bolt in a semiautomatic or automatic weapon and/or to lock the bolt in an open position upon the firing of the last round in the magazine.
There has never been a successful attempt to create user friendly and reloadable rifle cartridge specifically designed to restrict the internal capacity of the casing to contain powder thus resulting in the subsonic travel of the projectile. Such a case has to be easily reloaded by the shooter with a minimal level of expertise and equipment, utilizing only the standard reloading components of powder, primer and bullet.

Cited documents: US2006081148 BEAL

SUMMARY OF INVENTION

The present invention proposes to create a user friendly reloadable rifle cartridge which will allow the use of any standard weight and configuration of rifle projectiles to be utilized and to fire consistently from round to round in an accurate and subsonic manner. The cartridge cases can be produced in any current rifle caliber and externally will appear identical to commercially available ammunition cases as to physical dimensions. Starting with the widest end of the case, known as the head which has been machined to allow an edge to be grabbed by the rifle extraction device, moving up the case is a tapered cylindrical main body resulting in a reduced circumference known as a shoulder, and culminating in the neck of the case at one end. Within the neck is a cavity of a specific diameter corresponding to the desired caliber of projectile to be utilized in conjunction with this cartridge. As part of the design of the head of the case, a machined section is created to provide either a rimmed or rimless head for the case to be extracted from the chamber of the rifle by the extraction mechanism. Additionally in the center of the head, a cavity is machined into it, known as the primer pocket, designed to facilitate the insertion of an ignition charge known as the primer.
Within the primer pocket is machined a small hole which extends into the secondary cavity called a primer hole designed to allow the ignition charge to burn through into the secondary chamber and ultimately up into the powder chamber igniting the propellant charge. However, it is proposed that the external surface of the cases may be colored in a bright and easily identifiable manner as to clearly separate the subsonic rounds from the standard ammunition cases, and to further facilitate locating them in the field if dropped inadvertently.

The internal structure of the rifle case is substantially altered from that which exists in standard ammunition cases. The interior of the case is designed to produce a powder chamber of restricted size, extending from the top of the neck of the case, downward into the main body of the case. Thus allowing a substantially smaller amount of propellant to be utilized and yet still fills the case adequately to create consistent pressures and continuously accurate fired rounds. A secondary cavity is created within the case, from the bottom of the powder chamber towards the primer pocket at the head of the round, allowing a de-capping rod to pass through the secondary chamber and be utilized to remove the spent primer in preparation for reloading.

The cases will be manufactured from either mild steel, stainless steel, brass, copper bronze or aluminum depending upon the desire of the client. Brass, being the most widely used for reloading, would be suggested as the prime metal of choice.

An important aspect of the proposed invention is that the powder to be utilized in the reloadable case is a relatively slow burning type of rifle powder. This powder provides a rapid peak in pressure build up within the case, but contrary to fast burning powders, the pressure build up produced by the slow burning powder does not fall off sharply, but rather it platforms, so that there is sustained pressure within the chamber to assist in working a rifle action.

DETAILED DESCRIPTION OF INVENTION

With reference to the accompanying Figures, a vertical representation of the exterior of the subsonic cartridge is depicted in FIG. 1 and includes as part of the case an open end Al, then extending downward to the neck A2, widening to the shoulder A3, the main body of the case A4 and culminating in the head of the case A5 at the bottom. Depicted in FIG 2 is the representation of the face of the head section lying horizontally, including A5 being the outer rim of the head, B1 showing the machined depression in the head called the primer pocket which will have the primer inserted, and within the center of the primer pocket is the primer hole B2 through which the ignition charge from the primer is fired into the main body of the case.

Represented in FIG.3 is the cross section of the interior of the case showing the powder chamber C2 within which the majority of the propellant is placed. The interior case wall thickness is indicated as C1, which serves to restrict the size of the powder chamber. The secondary chamber is indicated as C3, which joins the primer pocket to the powder chamber, it also contains propellant in a loaded cartridge and provides a guiding cylinder within which the primer de-capping rod slides into prior to removing the spent primer. A representation of the cross section of some of the external case features are included as A2, the neck, A3 the shoulder, A4 the body and A5 the head are shown as well as B 1 the primer pocket and B2 the primer hole.

The representation depicted in FIG. 4 indicates a cross section of a standard rifle case containing a subsonic powder charge. This includes a representation of the projectile D1 inserted within the case, showing the standard case wall thickness as D2. The subsonic powder charge is indicated as D3 and the available surplus space within the standard case is indicated as D4. Once again the primer pocket of B 1 and the primer hole as B2 are shown to indicate position of primer charge as it relates to the propellant charge. The representation depicted in FIG.5 indicates all of the same features as in FIG.
4 but as the case has been angled upward it shows the relative position of the propellant charge D3 to the primer pocket B 1. The representation depicted in FIG. 6 indicates the same case as in FIG. 4 but showing the effects of the angle of the case on the propellant D3 in relation to the primer pocket B 1. Both FIG. 5 and FIG. 6 show the inconsistent propellant ignition from that of FIG. 4 due to the excess case capacity within the case when reducing the powder capacity to what would create a subsonic charge.

Represented in FIG. 7 is a cross section depiction of the subsonic case as in FIG. 3 but with both a representation of a projectile inserted in the case neck and the position of the propellant charge D3 within the case powder pocket C2 and the secondary chamber C3, as it relates to the position of the primer pocket B1 and Primer hole B2. What is represented in FIG. 8 is the same case as in FIG.7 but now in a horizontal manner showing no propellant movement within the powder chamber, and maintaining a constant contact with the primer pocket B1 andd the primer hole B2. Both FIG.9 and FIG. 10 indicate the same case as in FIG.7 but shown in an angled up and angled down position to demonstrate there is no propellant movement within the powder chamber.

Thus with the reloadable subsonic case design, the resultant primer ignition charge will contact the propellant charge in an identical fashion each time it is fired regardless of the attitude to which the case is angled. Thus resulting in the consistent performance of the projectile from round to round, given identical propellant charges and projectile weights.

The depiction of the item in FIG. 11 and subsequently in 1 l a, 1 lb and l lc is a representation of the de-capping rod, designed to be utilized with the subsonic reloadable rifle case, consisting of a threaded striking plate E1, which is threaded onto the threads on the top of the pin shaft at E2. The de-capping rod shaft indicated as E3, then reduces in size as indicated in E4 to fit into the secondary chamber C3. The final extension of the de-capping rod depicted as E5 is the de-capping pin, used to fit through the primer hole B2 and remove the spent priuner seated in the primer pocket B1. The depiction of three different sizes of de-capping rods as in FIG 11a, 11b and l lc, is a representation of the various sizes of the de-capping pin as would be required to insert into a variety of reloadable subsonic rifle cases designed in different calibers. The representation in FIG. 12 indicates the threaded striking plate El in both a side and face view, also showing the threaded hole in the niiddle of the striking plate E6. The diagrams represented in FIG. 13, and subsequently 13a, 13b and 13c, indicate a representation of the various sizes and designs of the reloadable subsonic rifle cases that will require a correspondingly sized de-capping rod to allow ease of reloading the subsonic rifle cartridge case.

DESCRIPTION OF DRAWINGS
FIG. 1 is a schematic representation, showing the exterior of the reloadable case from a lateral view of the side.
FIG. 2 is a schematic representation, showing the exterior of the reloadable case from and end view of the head.
FIG. 3 is a schematic representation, showing a sectional view of the design of the interior of the case depicted in FIG. 1.

FIG. 4 is a schematic representation, showing a sectional view of a standard rifle cartridge case lying horizontal containing a subsonic charge of propellant.

FIG. 5 is a schematic representation, showing the sectional view of the case from FIG. 4 with a subsonic charge of propellant and elevated in an upward angle to show propellant movement within the case.
FIG. 6 is a schematic representation, showing the sectional view of the case from FIG. 4 with a subsonic charge of propellant and angled downward to show propellant movement within the case.
FIG. 7 is a schematic representation, showing the sectional view of the case from FIG. 1 with a subsonic charge of propellant.

FIG. 8 is a schematic representation, showing the sectional view of the case from FIG. 1 with a subsonic charge of propellant, lying horizontal, and showing no propellant movement within the case.

FIG. 9 is a schematic representation, showing the sectional view of the case from FIG. 1 with a subsonic charge of propellant and elevated in an upward angle to show no propellant movement within the case.

FIG. 10 is a schematic representation, showing the sectional view of the case from FIG. 1 with a subsonic charge of propellant and elevated in a downward angle to show no propellant movement within the case.

FIG. 11 (11 a 11 b 11 c) is a schematic representation, showing the design of the primer de-capping rod necessary for the reloading of the subsonic cartridge case.

FIG. 12 is a schematic representation, showing the design of the threaded striking plate which threads onto the de-capping rods in FIG. 1 FIG. 13 (13a, 13b, 13c) is a schematic representation, showing an example of the various designs of the subsonic cartridge cases, requiring a specifically cut de-capping rod to be manufactured to fit into the case for reloading.

Claims

1. A rifle cartridge casing, cylindrical in design having its external dimensions matching the external dimensions of any particular widely known and accepted rifle cartridge case currently in use.

2. Where item in claim #1 has an opening at one end, referred to as the neck, below this, an expansion of the casing known as the shoulder, a cylindrical length known as the body and another but smaller opening called a primer pocket, at the opposite end which is known as the head.

3. Where the opening of the neck is of sufficient diameter to allow the insertion of a particular size or caliber of rifle bullet, or projectile, intended to be fired from a corresponding rifle action of the same caliber.

4. Where the opening at the head known as a primer pocket, is of sufficient size to allow the insertion of a primer which is utilized to ignite the propellant, upon striking the primer with the firing pin of the firearm in which the cartridge has been inserted having the proper corresponding action and chamber designed for that cartridge.

5. Where item in Claim #1 has an internal cavity, known as a powder chamber, extending into the case from the neck end towards the head end of the case and of sufficient depth and diameter as to allow a measured amount of propellant or gun powder to be inserted, substantially filling the powder chamber. Where upon ignition or firing of the gunpowder, it will propel the projectile from the rifle barrel at subsonic speeds, that being less than approximately 1086 feet per second at sea level. The resultant cavity forming the powder chamber is substantially reduced in volume from what would be standard for that particular rifle caliber cartridge casing designed to hold a fall powder charge.

6. Where item in Claim #1 has a secondary and smaller internal cavity extending from the deepest portion of the powder chamber, towards the head of the case and terminating 3mm from the deepest portion of the opening machined in the head known as the primer pocket.

7. Where item in Claim #1 has another machined cavity known as a primer hole approximately 1mm in diameter extending from the deepest center portion of the primer pocket to the deepest end of the secondary cavity, a distance of 3mm, and joining the two cavities. Said cavity allows, upon striking or firing of the primer, the incendiary charge in the primer to ignite the propellant contained within the secondary cavity and up into the powder chamber, providing sufficient gas pressures to propel the projectile out of the rifle barrel at subsonic speeds.

8. Where the diameter of the secondary cavity is of sufficient size as to allow the insertion of a primer de-capping rod into the upper neck opening of the case and extending down through the powder cavity, through the secondary cavity and contacting the spent primer through the primer hole in the head in order expel the spent primer from the case in preparation for reloading of the cartridge.

9. Where the walls of the powder chamber are joined integrally with the walls of the outer case, formed by either pouring a molten substance into the case which hardens prior to the machining out of the powder chamber cavity or by manufacturing the cartridge case from one homogeneous length of metal.