EP0103575B1

EP0103575B1 - A pellet for an air, gas or spring gun

Info

Publication number: EP0103575B1
Application number: EP19820903050
Authority: EP
Inventors: Michael John Robins
Original assignee: Individual
Current assignee: Individual
Priority date: 1981-10-06
Filing date: 1982-10-06
Publication date: 1987-08-19
Also published as: EP0103575A1; DE3277027D1; WO1983001300A1

Abstract

A sabot (1) for use in combination with a pellet (4) for an air, gas or spring gun comprises a plurality of members (3) which extend in the direction in which the pellet is intended to be propelled, said members being provided with portions (40) which, when the sabot and pellet combination is in a gun barrel, extend inwardly to engage the pellet to prevent forward movement of the pellet in the sabot.

Description

This invention relates to a sabot for use in combination with a pellet for an air, gas or spring gun.
It is known to use a sabot in conjunction with a bullet supplied in a cartridge for use in firearms. In such a cartridge, see, e.g. GB-A-2013312, the bullet is seated in the sabot and the sabot is seated in the leading end of the cartridge case. When the firearm is fired, the buffet together with the sabot is propelled along the barrel. Once the bullet and sabot have left the barrel of the firearm, the sabot is separated from the bullet by air resistance and rapidly falls to the ground. The bullet, which has a smaller diameter than the bore of the firearm and hence a reduced air resistance as compared with a conventional bullet, continues at a higher velocity and hence with a flatter trajectory.
It is not, however, possible to use such known forms of sabot with a pellet for an air, gas or spring gun. This is because there is, of course, no cartridge case which serves to hold the bullet or pellet and sabot together until the moment at which the gun is fired.
FR-A-2343218 disclosing a device comprising the constructional features of the preamble of claim 1) and US-A-3568603 propose a method of solving this problem in which a sabot comprises a plurality of forwardly extending petals which are bendable radially outwardly to release the shot but which are retained in engagement with the shot by a slidable collar which slides rearwardly of the sabot before or during firing to release the petals. Such arrangements, however, suffer from the disadvantage that the collar causes relatively high friction with the gun barrel. Whilst this may not be a problem in firearms employing an explosive charge, it is very serious in air guns owing to the limited energy available. Further, these known devices consist of multiple parts and are costly to manufacture and assemble. It is also a problem in the prior art that the bullet or other pellet should desirably have a good seal with the surface of the bore in spite of variations in the diameter of the bore. Such differences are particularly marked when comparing an Imperial size bore with the equivalent metric size. Conventional pellets which are suitable for use in a standard Imperial size bore will not fit the equivalent metric bore, and vice versa.
It is the object of the invention to overcome these disadvantages of the prior art.
According to the invention, there is provided a sabot in combination with a pellet for an air, gas or spring gun wherein the sabot comprises a base portion for receiving a rear end of the pellet, and a plurality of members which extend from the base portion in the direction in which the pellet is intended to be propelled, said members being provided with forward portions which, when the sabot and pellet combination is in a gun barrel, extend inwardly to engage the pellet forward of the greatest diameter of the pellet to prevent forward movement of the pellet in the sabot, characterised in that the sabot is of unitary construction and each member is bendable at the junction between its forward portion and the rest of the member whereby the members may bend inwardly and outwardly so as to accommodate variations in the bore of the gun whilst maintaining resilient engagement with the bore and with the pellet forward of the greatest diameter of the pellet.
The sabot is thus capable of adapting to variations in bore.
The invention offers many advantages over earlier pellets: the sabot forms a good seal with the barrel with low friction and retains the pellet reliably. When the pellet and sabot leave the gun barrel the resilient members rapidly disengage the pellet and spread to provide high air resistance which results in the sabot separating rapidly from the pellet whereupon the pellet continues with substantially lower drag than is experienced by a conventional pellet fired from a gun of the same calibre. Greater range, accuracy and target penetration are thus assured.
In one preferred embodiment, said members comprise a plurality of fingers extending from a base portion. In the relaxed state of such a sabot, the fingers extend both in said direction and radially outwardly, freely allowing a pellet to be inserted in and removed from the base portion. However, when the pellet and sabot are inserted in a gun barrel, the fingers are bent radially inwardly about their junctions with the base portion so that the leading ends of the fingers close about the leading end of the pellet. When the pellet and sabot leave the barrel of the gun, the fingers spring apart and the high air resistance of the sabot causes it rapidly to separate from the pellet and fall to the ground.
It is further preferred for the pellet to have a frusto-conically tapered trailing end which engages a correspondingly shaped portion of the sabot. This feature provides a wedging effect as the combination travels along the gun barrel, with the light weight sabot forced onto the heavier pellet by the pressure of the propelling air. It is, however, preferred for a planar rear surface of the pellet to engage the sabot to limit this wedging effect to facilitate separation of the pellet and sabot in flight.
An embodiment of the invention will now be described by way of example with reference to the attached drawings, in which:

Figure 1 is a plan view of an embodiment of a sabot according to the invention, together with a pellet for an air, gas or spring gun;
Figure 2 is a section through the sabot of Figure 1 on line II-II, indicating in broken lines the configuration of the sabot when the combination of the sabot and the pellet are in the barrel of a gun;
Figure 3 is a view of the sabot and pellet of Figures 1 and 2 in a gun barrel, viewed from the muzzle of the gun; and
Figure 4 is a section through a loading device for a sabot and pellet according to the invention.

As shown in Figures 1 to 3, a sabot 1 made of a resilient plastics material comprises an annular base portion 2 from which extend six fingers 3 in the direction in which a pellet 4 made, for example, of steel or copper-coated lead is intended to be fired. The fingers 3 are bendable about their junctions with the base portion 2 as indicated by the deflected position of the fingers shown by broken lines in Figure 2. Each finger 3 is angled at a line 5 roughly one-third of its length from its front end so as to include a portion 6 which extends inwardly when the sabot and pellet are in the bore 8 of a gun barrel 9. As in clearly shown in Figures 2 and 3, each finger is provided with a pip 40 of triangular cross-section on its inside surface, which engages the pellet forward of the maximum diameter of the pellet indicated by the circumference 7 in Figure 3, when the sabot and pellet are in a gun barrel, so as to retain the pellet within the sabot. Each finger further includes a pip 41 also of triangular cross-section on its outside surface. The engagement of the pips 41 with the bore increases the pressure exerted by the pips 40 on the pellet. Because the fingers contact the bore at only a few points of the circumference, there is low friction between the bore and the sabot.
When the combination of the sabot and pellet are inserted in a gun barrel, not only do the fingers bend relative to the base portion at their junctions with the base portion, but also the fingers bend at the line 5 so as to conform with the diameter of the bore.
The base portion 2 of the sabot includes an outwardly extending annular flange 10 which engages the rear end of the barrel when the pellet and sabot are loaded, and engages the rifled bore 8 of the gun barrel as the pellet and sabot travel along the bore. The flange 10 may have a different cross-section from that shown, e.g. its forward surface may be curved.
The inside surface of the base portion 2 includes a frusto-conically tapered trailing end 12 of the pellet 4. This assists in the engagement between the pellet and sabot as they travel along the gun barrel by virtue of the fact that air or gas pressure behind the combination tends to force the light weight plastics sabot onto the much heavier pellet so as to generate a wedging effect. Spin imparted to the sabot by the rifling of the gun barrel is thus in turn imparted to the pellet.
The base portion 2 further includes an aperture 13 therethrough. This aperture may be omitted, or replaced by a small diameter aperture so as to increase the air resistance of the sabot after it has separated from the pellet. The aperture has a smaller diameter than the flat rear surface of the pellet. The engagement of the sabot with the flat rear surface limits the wedging effect between surface 11 of the sabot and surface 12 of the pellet to permit rapid separation of the sabot and pellet after leaving the gun barrel. It will be appreciated that the sabot should preferably be as light as possible as compared with the pellet, in order to improve the separation of the sabot and pellet and to minimize the amount of momentum lost. On the other hand, the angle of the tapered surface 11 relative to the axis should be such as to provide sufficient grip to spin the pellet as the combination travels along the rifled bore. Such spin is necessary to stabilise the pellet in flight. An included semi-angle of about 15° has been found to give good results.
Referring now to Figure 4, a device for loading a sabot and pellet in a gun comprises a tubular barrel 17 having substantially the same or a slightly greater bore than the gun with which it is to be used.
An outwardly projecting annular stop 18 is provided on the outside of the barrel 17. A plunger 19 includes a pusher member 20 which enters the barrel 17 so as to be slidable therealong and to engage the rear end of a sabot and pellet combination inserted in the front end of the barrel 17. The plunger 19 further includes a manually engageable portion 21 which surrounds the barrel 17 and includes an annular inwardly extending stop 22 for engagement with the stop 18 in the rearmost position of the plunger 19.
In order to load a gun using the device shown in Figure 8, the pellet 4 is first placed within the sabot 1 which is in the relaxed state shown in Figure 1 and in solid lines in Figure 2. The combination is then pushed into the leading end of the barrel 17 of the device, so that the fingers of the sabot are compressed about the pellet. Whilst the fingers may be compressed so as to be in contact with the pellet, this is not essential. It is sufficient for the fingers to be compressed so as to prevent the pellet from escaping from the sabot and to enable the combination to enter the barrel. Insertion of the combination beyond the illustrated position is prevented by engagement of the sabot with the pusher 20 and engagement between the stops 18, 22. The nose of the pellet and sabot combination is then inserted in the rear end of a gun barrel, whereafter the plunger 19 is moved forwardly, so that the pusher member 20 pushes the pellet and sabot combination into the gun barrel until the flange at the rear of the sabot engages the rear end of the gun barrel. Further forward movement of the plunger is limited by engagement of the base of the plunger with the rear of the tubular barrel 17.
It will be appreciated that whilst the sabot according to the invention has been illustrated in combination with a bullet-shaped pellet, it could be adapted for use with any desired form of pellet, for example a ball. Whilst the pellet is preferably made of steel which is not damaged during storage, lead pellets could also be used. Alternatively, other metals, e.g. copper, or alloys may be used, or plastics with a metal filler.
In a modification, webs in the form of thin collapsible membranes may be provided between the fingers 3. These help the fingers to spring out when the pellet and sabot leave the gun barrel and provide increased air resistance to the sabot to assist in separating the pellet and sabot.
The embodiments in which the aperture 13 is omitted have the advantages that the base portion 2 is strengthened and the air resistance to the sabot is again increased.

Claims

1. A sabot (1) in combination with a pellet (4) for an air, gas or spring gun wherein the sabot comprises a base portion (2) for receiving a rear end of the pellet, and a plurality of members (3) which extend from the base portion in the direction in which the pellet in intended to be propelled, said members being provided with forward portions (6) which, when the sabot and pellet combination is in a gun barrel, extend inwardly to engage the pellet forward of the greatest diameter (7) of the pellet to prevent forward movement of the pellet in the sabot, characterised in that the sabot is of unitary construction and each member (3) is bendable at the junction (5) between its forward portion (6) and the rest of the member (3) whereby the members may bend inwardly and outwardly so as to accommodate variations in the bore of the gun whilst maintaining resilient engagement with the bore and with the pellet forward of the greatest diameter of the pellet.

2. A combination as claimed in claim 1 wherein a space is defined between each member and the pellet immediately rearwardly of the point of engagement of the forward portion with the pellet forward of the greatest diameter of the pellet and in the region of said junction between the forward portion and the rest of the member.

3. A combination as claimed in claim 1 or 2, wherein siad plurality of members are bendable about their junctions with the base portion.

4. A combination as claimed in any preceding claim, wherein each member is adapted to resiliently bear on a gun barrel bore at a location in the vicinity of the point of engagement of the member with the pellet.

5. A combination as claimed in any preceding claim, wherein the pellet has a frusto-conically tapered trailing end (12) which engages a correspondingly shaped portion (11) of the sabot.

6. A combination as claimed in any preceding claim, wherein the pellet has a planar rear surface engaged by the sabot.

7. A combination as claimed in any preceding claim, wherein the sabot is adapted to engage a gun barrel bore at the trailing end of the sabot.

8. A combination as claimed in any preceding claim wherein said members are adapted to spring away from the pellet to disengage the pellet when it leaves the gun barrel.