WO1993007439A2

WO1993007439A2 - Mortar and ammunition therefor

Info

Publication number: WO1993007439A2
Application number: PCT/GB1992/001838
Authority: WO
Inventors: Anthony Charles Buxton; Stephen George Goward; David Patrick Alexander Singleton
Original assignee: Royal Ordnance Plc
Priority date: 1991-10-09
Filing date: 1992-10-09
Publication date: 1993-04-15
Also published as: AU2694692A; GB9121343D0; GB2260390A; WO1993007439A3; ZA927794B; GB9221292D0

Abstract

A breech loading mortar system is described, the system having means to prevent a round of ammunition from either sliding backwards before the breech can be closed or forwards when the barrel is depressed. The means for preventing the backwards sliding of the ammunition are resiliently biased latch means (64) mounted in recesses in the breech block of the mortar. The means (51) for preventing the forward sliding of the ammunition are mounted on the ammunition itself.

Description

MORTAR SYSTEM

The present invention relates to mortar systems, and particularly to means for locating a mortar bomb prior to firing.

Mortars are generally relatively simple weapons which, in their simplest forms, may have no moving parts. A round of ammunition is dropped into the muzzle of the barrel which is fixed to a baseplate, the firing cap of the round strikes a fixed firing pin in the barrel which ignites a propellant charge and the round is fired from the barrel.

The type of mortar described above is generally fired from a position without cover, due mainly to the need for safety in that the ammunition is manually loaded into the barrel muzzle and exits very shortly afterwards thus rendering any form of overhead cover dangerous, especially with ammunition having a proximity fuse. Desirably, such overhead cover, if practicable, might provide either camouflage, to hide the position of the mortar, or protection against counter-fire; or more desirably still, both of these things.

Mortars have often been light and relatively easily man-portable, with the governing factor for mobility of the weapon system usually being the ability to carry sufficient ammunition. As the calibre size of the mortar weapon itself increases so too does the size and weight of the corresponding ammunition thus making the man-handling of such weapons impracticable.

It is known that mounting a mortar on a vehicle provides for increased effectiveness, increased mobility and for greater protection. This is due firstly to the fact that a heavier mortar and a sufficient supply of ammunition may be carried, and secondly, that the position of the weapon and its operators may be frequently and rapidly changed, thus making effective counterfire more difficult. Mortars may be mounted on relatively small and unarmoured vehicles. However, greatest benefit in terms of protection for the user may be derived from mounting the weapon on an armoured vehicle, and preferably, to have the mortar on a turreted vehicle for greatest protection to the users.

Evidently, it would not be deriving the most protection that such a vehicle may afford if the operator still has to load the ammunition manually into the barrel muzzle from outside. Therefore, a mortar having a breech loading mechanism is of greatest benefit when used in conjunction with an armoured vehicle. Such weapons are known and are often referred to as "gun mortars".

A breech loading mechanism is one where the projectile is loaded into an open end of the barrel, remote from the muzzle, the open end being closed with a breech closing mechanism prior to firing of the ammunition.

To maximise the effectiveness of the system it is desirable for a vehicle mounted mortar to be able to fire from a range of barrel elevation from about -5 to +80 degrees.

When a breech loading mechanis is employed it is necessary to ensure that the ammunition is held against the breech closing mechanism so that it is in the correct position for the firing pin to strike a percussion cap, for example. There are three possible things which may happen when loading ammunition into the barrel via the breech, bearing in mind that mortars have smooth bores in which the ammunition may slide relatively easily. Firstly, the barrel elevation may be such that the ammunition stays where it is placed; or secondly, the barrel elevation may be low so that the ammunition slides forward away from the breech; or thirdly, the barrel elevation may be high so that the ammunition slides backwards before the breech can be closed.

It is an object of the present invention to provide means for the positive location of ammunition in the barrel of a mortar relative to the firing mechanism of said mortar whilst a breech mechanism is being closed. According to the present invention there is provided a mortar weapon for firing breech loaded mortar ammunition rounds, having a barrel and including a breech assembly through which the ammunition is loaded into the barrel, breech closing means for closing the breech, ammunition propeliant charge firing means which in operation act via the breech assembly to ignite the ammunition propellant charge, characterised by means for the positive location, prior to firing, of the ammunition within the barrel relative to the ammunition propellant charge firing means.

Preferably the means for positive location of the ammunition acts to prevent both excessive forward and backward movement of the ammunition when the ammunition is loaded in the mortar barrel and before the breech is closed. Generally the prevention of forward movement of the ammunition is important when the mortar is operated in low or negative elevation and the prevention of backward movement important when the mortar is in a high elevation.

The means for positive location of the ammunition against forward motion whilst the barrel is deployed in a low or negative elevation may include a member associated with the ammunition round itself, at least one edge of which co-operates with a recess formed in the barrel adjacent the breech end of the barrel. The member may be in the shape of a disc or flat plate associated with the ammunition itself.

In one arrangement, the member associated with the ammunition itself may be of a combustible material which will combust and degrade on ignition of the propellant charge which will not influence the ballistic characteristics of the ammunition, the combustion debris being ejected from the muzzle. Because mortar ammunition generally has augmenting cartridges which are removed by the operator to adjust muzzle velocity prior to firing, the addition of a location disc does not affect the rate of fire of the mortar. The combustible disc may, for example, be made from impregnated cardboard or any other suitable material.

Alternatively the member associated with the ammunition may be in the form of a metal clip positioned over or on the fins of the ammunition, which either remains in the barrel after firing of the

SUBSTITUTE SHEET ammunition or drops out automatically when the breech means is opened. If the metal clip remains in the barrel it can either be removed manually or by using a mechanical extractor or removed automatically by a device associated with the breech which operates to remove the metal clip upon opening of the breech.

In one embodiment of the invention the metal clip comprises a disc or plate mounted at the rear end of the fins of the ammunition with its plain perpendicular to the longitudinal axis of the mortar barrel. The clip has a hole in the centre to allow operation of the firing pin. The clip has one or more arms projecting generally perpendicular to the plain of the disc or plate which arms have projections which cooperate with the fins of the ammunition to engage or hold the mortar bomb. In use the circumferential edge of the disc which may be partially cut away fits into a recess in the barrel to prevent forward movement of the ammunition.

In another embodiment of the invention the means for the positive location of the ammunition comprises a generally cylindrical sleeve which is of a size which enables It to fit both within the barrel of the mortar and over the rear of the round of ammunition, preferably over the length of both the fins and augmenting propellant charges. The sleeve is crimped or flattened at each end into an ovoid cross section to form an interference fit within the barrel and has at the rear of the sleeve, means for preventing the sleeve sliding forward which cooperate with a recess in the barrel, and means for preventing the ammunition sliding backwards within the sleeve.

The means for positive location of the ammunition against backward motion of the ammunition may be arranged to operate when the ammunition has been loaded but before the breech closing means is operated, and in one embodiment, may comprise detent latch means associated, with the breech means. The breech means and breech closing means may be of known form having co-operating portions of generally f rusto-conical form and interrupted threads, relative rotation of one allowing the breech closing means to be engaged with and disengaged from the breech means. The detent latch means referred to above may be mounted within the thread interruptions of the breech

SUBSTITUTE SHEET means. The detent latch means may be resiliency biased towards a generally inward radial direction relative to the axis of the breech means in order to engage with the rear portion or fins of a loaded round of ammunition to prevent it from sliding backwards out of the breech means. Operation of the breech closure means acting to depress the detent latch means into recesses associated with the thread interruptions to allow closure of the breech.

It should be understood that the term "positive location" as referred to herein means the ammunition being held in desired position(s) against forward or backward movement once the ammunition has been loaded. The position of the ammunition when positively located against forward movement may be different from the position of the ammunition when positively located against rearward movement. For example the positive location against forward movement may operate with the ammunition further forward in the barrel than the position of the ammunition when the means for positively locating against backward motion is in operation. The action of operating the breech closing means may move the loaded ammunition further into the barrel to the eventual firing position, which may be the position where the means for positive location of the ammunition against further forward movement comes into effect.

Preferably, the detent latch means are positioned in the breech behind obturator means. The advantage of this is that the detent latch means are not damaged by the temperature and contamination associated with combustion of the propellant charge.

The obturator is that part of a breech assembly which seals the propellant charge combustion gases into the barrel and prevents them from being ejected through the breech and entering the crew compartment.

The mortar may, of course, have many refinements including such features as a control system for aiming purposes and a recoil shock absorption system for example. Such features may be provided in known manner and will not be described further. In order that the present invention may be more fully understood, an example will now be described by way of illustration only with reference to the accompanying drawings, of which:

Figure 1 shows a rear view of a breech assembly looking along the barrel axis;

Figure 2 shows a section through the plane AA of Figure 1 looking in the direction of the arrows;

Figure 3 shows a part view of the breech means of Figures 1 and 2 with detent latch means in place for preventing backward movement of the ammunition when loaded;

Figure 4 shows a perspective line drawing of the detent latch means of figure 3;

Figures 5A to 5D are a sequence of schematic drawings showing a round of ammunition being loaded and the breech being closed prior to firing of a mortar having the detent latch means illustrated in figure 3;

Figure 6A shows a round of mortar ammunition having one means of locating it against sliding forward and Figure 6B shows the location means removed from the round of Figure 6A.

Figure 7A shows a side view and Figure 7B an end view of an alternative detent latch means to the detent latch means illustrated in Figure 3.

Figures 8A to 8D are a sequence of drawings showing a round of ammunition being loaded and the breech being closed prior to firing of a mortar with the alternative detent latch means of Figures 7A and 7B.

Figure 9A and 9B shows perspective views of a round of mortar ammunition having an alternative means of locating it against sliding forward; and

Figures 10A and 10B show perspective line drawings, one from each side, of the alternative means illustrated in Figures 9A and 9B, of locating the ammunition against sliding forward Figure 11 shows a perspective line drawing of a yet further means of positively locating a round of ammunition within the barrel against both forward and backward movement. Referring now to the Figures and where the same features are denoted by common reference numerals.

A breech assembly is shown generally at 10 and includes breech means, in this case a breech block 12, breech closing means, in this case a breech plug 14, an axial vent bolt 16, obturator means 18, firing means 20 which will not be described further and a barrel 22, only the breech end 24 of which is shown and which is screwed into the breech block 12 by co-operating screw threads 26. The whole breech 10 and and barrel 22 assembly is supported on a cradle (not shown) and has a recoil system (not shown) to which the recoil shock loads are imparted by a yoke member 28. The cradle and recoil system are provided in known manner and will not be described further. The breech block 12 has a tapered female threaded portion and the breech plug 14 has a tapered male portion, each tapered portion having co-operating screw threads 30, 32. The block 12 and plug 14 are moved into and out of engagement by swinging the breech plug 14 about a pivot axis 34, actual engagement being effected rapidly by interruptions 36, 38 in the threads 30, 32 respectively. The plug 14 is shown in Figure 2 in Its disengaged position by the chain dashed line 40. The plug 14 is rotatable about the axis 42, a handle 44 being provided to rotate the plug between an open position stop 46, allowing disengagement from the block 12, and a closed position stop 48 where the plug 14 is in the shut position and from where the weapon may be fired. Various safety interlock features which prevent accidental firing are incorporated in known manner, and these will not be described further. The breech plug 14 has an axial vent bolt 16 having a generally mushroom shaped head 50 at the nose portion 52. The purpose of the vent bolt 16 is to provide resistance to the temperature and corrosive effects of the ignition propellant charge 54 housed in the tube 55 on the rear end of the round of ammunition (see Figures 6 A and 9A), partially seal the breech end 24 of the barrel 22 and to provide access to the percussion firing cap (not shown) of the round of ammunition by the firing means 20. In between the nose portion 52 of the breech plug 14 and the rear face 56 of the head 50 are obturator means, in this case an obturator pad 58 which comprises a reinforced elastic material, the purpose of which is to prevent completely any propellant gases escaping from the barrel 22 through the thread interruptions 36, 38 of the breech block 12 and plug 14 during firing of the propellant charge and entering the crew compartment (not shown) of the vehicle (not shown). Resilient biasing means, in this case a compression spring 60 is provided to keep the obturator pad 58 firmly sandwiched between the rear face 56 of the head 50 and the nose portion 52 of the breech plug 14. A recess 62 is provided in the breech end 24 of the barrel 22 adjacent the axial vent bolt head 50. For the sake of clarity, detent latch means have not been shown in Figures 1 and 2, but one embodiment is shown in Figures 3 and 4 and an alternative in Figures 7A and 7B.

The detent latch means, in the embodiment of Figures 3 and 4 comprises resiliently biased latches 64 which are mounted by screws 66 in recesses 68 within the thread interruptions 36 of the breech block 12. The latches 64 are permanently biased towards the position shown in Figure 3 by a torsion spring 70 associated with a pivot shaft 72 about which a tee-shaped portion 74 of the latch 64 pivots. The latches are so arranged that when the breech plug 14 Is swung into the closing position about the pivot axis 34, the thread portions 30 push the latches arm portions 74 down into the recesses 68 against the biasing effect of the spring 70 to allow the breech to be closed and the plug to be rotated to the stop 48.

In operation with the breech plug in the position indicated by the dashed lines 40, (see also Figure 5A), a round 80 of mortar ammunition is inserted through the open breech block 12 into the end 24 of the barrel 22. The action of inserting the round 80, depresses the latch arms 74 into the recesses 68 until the fin arrangement 82 has passed over the tee-pieces 74 of the latches 64 (see Figure 5B). Once the round has passed over the latches, they spring up under the influence of the torsion springs 70 to prevent the round from sliding backwards when the barrel is at high angles of elevation (see Figure 5C). The round rests against the latch arm portions 74 until the breech block is closed with the breech plug, the action of closing the breech plug serving to depress the latch arm portions 74 and to push the round to its final firing position (see Figure 5D).

The detent latch mechanism of Figures 3 and 4 limits the rearward movement of the round of ammunition to a position where the fin arrangement 82 (Figure 5C) is located well to the rear of the breech chamber, and it has been found that upon closure of the breech plug there is a possibility that the fins of the round of ammunition may interfere with a breech chamber wall which could produce damage to the fins and/or breech chamber wall.

The alternative detent latch mechanism shown in Figures 7 A and 7B limits the rearward movement of the round of ammunition to a position further forward in the breech, so that when the breech plug 14 is closed there is a decreased possibility of the fins of the ammunition interfering with the breech chamber wall. In Figure 7A a latch 64 has at its end nearest the pivot 72 a boss 96 with a flattened end face which, when the latch is in the open position i.e. the position for restraining the ammunition from rearward movement) bears on the surface of the plate 98 to limit the rearward movement of the latch. The latch 64 is thereby fixed in the open position at an acute angle to the forward direction of the ammunition thereby positioning the ammunition further forward in the mortar barrel. In Figures 7A and 7B the Tee-pieces 74 have fixed cylindrical end parts 99 and the biasing torsion spring is not shown.

When the elevation of the barrel is low, the round of ammunition may slide forward and this may be prevented in one embodiment (Figures 6A and 6B by a location disc 90 positioned on the round 80 between the fin arrangement 82 and the augmenting charges 84 which are usually employed on such ammunition to adjust muzzle velocity of the round. The disc 90 is made of a combustible material, in this case resin impregnated cardboard, the outer periphery 94 of which engages in the recess 62 formed in the end 24 of the barrel 22. As described above, during loading, the round again depresses the latch arm portions 74, and in this respect operates in precisely the same manner in that the round is then prevented from sliding backwards should the barrel elevation be changed. Closing of the breech plug again pushes the round forward so that the firing means 20 lie against the firing percussion cap (not shown) of the round. The round is prevented from sliding further forward by the frictional resistance between the disc periphery 94 and bore 96 of the barrel.

One possible disadvantage of using combustible material for the disc is that complete combustion may not occur, leaving combustible debris in the breech, which could be a safety hazard.

An alternative arrangement for preventing the round of ammunition from sliding forward is shown in Figures 9A, 9B and 10A, 10B. A metal clip 51, comprises a flat plate 53, which has diametrically opposite circumferential edges 55, and opposite flat edges 69. Spring projections 57 (Figures 10A, 10B) are each mounted on the inner surface of the plate 53 radially around a central hole 59 in the plate. Each spring projection 57 has a base 61 riveted to the plate 53 by rivets 63. The base 61 of each projection 57 has a lip 65 which for two of the projections fits into a slot 67 and for the third projection fits over one of the flat edges 69.

Each projection 57, has a lip 71 at its end remote from the plate 53 which is angled away from the centre of the hole 59 in the plate 53. Each projection also has a rivet 73 close to its free end adjacent the lip 71.

In operation the metal clip 51 is positioned over the fin arrangement 82 of the round of ammunition prior to loading. The spring projections 57 are positioned on the plate 53 in such a way that each will clip over the shaft 75 of the fin arrangement 82 between the vanes of the fin arrangement 82. The spring projections form an interference fit over the central core 75 of the fin arrangement and are sprung apart upon fitting over the ammunition by the action of the lips 71 on the vanes of the fin arrangement 82. The surface of the central shaft 75 of the fin arrangement 82 has shallow holes (not shown) which are of a size and are positioned such that when the clip 51 is clipped over the fins 82, the rivets 73 will readily locate in the holes of the fin shaft surface 75 and thereby grip the ammunition to prevent its sliding forward when the mortar is in low or negative elevation. Preferably shallow holes are located in a circumferential array one between each fin vane so that the clip 51 can be fitted onto the ammunition in a number of circumferential orientations.

Upon closure of the breech the round of ammunition 80 with the metal clip 51 in position is pushed forward by the breech plug 14 into its firing position. The plate 53 of the clip 51 rests in the recess 62 when the ammunition is in the firing position. The diameter of the plate 53, between circumferential edges 55, is greater than the internal bore of the mortar tube so that the clip cannot readily move further forward in the barrel 22.

The central hole 59 allows a firing pin (not shown) to pass through the plate 53 to ignite the ammunition propellant primer.

When the ammunition is fired, the clip 51 will remain in the recess 62, and when the breech plug 14 is swung open the clip will either fall out or can be removed by hand or with an appropriate extractor tool. It has been found in practice that the high temperature transferred from the ammunition to the clip is rapidly dissipated and removal by hand is, in many cases, possible. It is also possible to fit an automatic device for removing the clip 51 from the recess 62 which is operated by the opening movement of the breech plug.

. The clip 51 shown in Figures 9B and 9C may have any convenient means for positive positioning of the clip on the fin arrangement 82. For example the projections 57 may be longer and have inward directed lips which are arranged to fit or clip over the inner ends of the shaft 75 of the fin arrangement 82, between the fins and the augmenting propellant charges 84. The plate 53 of the clip 51 may be of any convenient shape that fits into the recess 62 and which will remain in the recess 62 when ammunition is fired. In one arrangement (not shown) the plate 53 is petal shaped with a number of petals corresponding to the number of vanes, or half the number of vanes. Furthermore the clip 51 may have any convenient number of projections 57 radially disposed preferably symmetrically, such that each will fit over the shaft 75 of the fin arrangement 82. The clip may be made of any convenient material, for example mild or hardened steel, and should have adequate circumferential edges 55 to provide purchase in the recess 62. The area of the plate 53 should be significantly less than the area of the mortar tube of the recess.

The recess 62 may be in the form of two or more spaced circumferential recesses machined in the same plane in the inner surface of the barrel, and the flat plate 53 of the clip 51 (Figures 9A, 9B and 10A, 10B) or the location disc 90 (Figures 6A and 6B) may have at least two corresponding raised circumferential edges which upon correct circumferential orientation will engage in the recesses. Alternatively the recess 62 may extend the entire circumference of the inner surface of the barrel and the flat plate 53 of the clip 51 or the location disc 90 may have a plurality of raised circumferential edges which fit in the recess.

It will be understood that the clip must be sufficiently strong to hold the round of ammunition against sliding forward at the lowest elevation of the mortar, but should not be so strong as to effect materially the ability of the round to readily disengage from the clip upon firing. The clip may be disposable or reusable.

Figure 11 shows another means for the positive location of the ammunition 80 in a mortar barrel. A cylindrical sleeve 11, made of plastic, metal or other suitable material has an external diameter which allows the sleeve to fit into the barrel, and has an internal diameter which allows the sleeve to fit over the fin arrangement 82 of the ammunition 80. As illustrated, the sleeve 11 is of sufficient length to fit over the entire length of both the fin arrangement 82 and the augmenting propellant charges 84.

On the circumference of the rear end A of the sleeve 11, a number of outwardly projecting lugs 13 are formed. Preferably the lugs are positioned in diametrically opposed pairs. The external lugs 13 are arranged to fit into the recess 62 (Figure 2) when the ammunition is loaded and to prevent the sleeve 11 from moving or sliding forward in the barrel.

The sleeve 11 also has a number of circumferential internally projecting lugs 15 at or adjacent the end A which, when the sleeve is fitted onto the ammunition act as stops against which the vanes of the fin arrangement 82 abut when the sleeve is fitted fully over the ammunition.

In use, the sleeve 11 is fitted over the ammunition before the ammunition is loaded into the barrel. The sleeves may be fitted when the ammunition is manufactured or fitted in the vehicle immediately prior to loading. If the sleeve is fitted when the ammunition is manufactured then it will be necessary to slide the sleeve at least partially off the ammunition when loading the ammunition in order to apply the desired augmenting propellant charges 84. The sleeve 11 is slid over the rear of the ammunition 80 and the internally projecting lugs 15 act as the stop for the vanes of the fin assembly 82. The forward end B of the sleeve is then slightly crimped or flattened either side of an axis shown horizontally in Figure 11 and marked as the 270-90 axis. The process of crimping or flattening of the forward end B of the sleeve causes the circular cross section of the sleeve to become ovoid in shape and the diameter at the crimping axis 270-90 is increased to the extent that at the front end B the sleeve is an interference fit when loaded with the ammunition in the barrel.

The rear end A of the sleeve 11 is also crimped in a similar way to the front end B, but along an axis (marked as 0-180 in Figure 11) which is at 90 degrees to the axis of crimping at the front end B. The crimping at the rear end A also produces an interference fit with the barrel when the ammunition with sleeve 11 is loaded.

The effect of the interference fit at the front and rear ends (B,A) of the sleeve 11, is to ensure that the sleeve will not move backwards in the barrel, for example at high mortar elevation, and that the ammunition in the barrel will not slide or move forward inside the sleeve at low or negative elevations. The internally projecting lugs 15 will act as stops to prevent the ammunition moving or sliding backwards at high elevations and the outward projecting lugs 13 fit into the recess 62 to prevent forward sliding or movement of the sleeve 11 at low or negative elevations. By crimping or flattening at four equally spaced circumferential locations (A and B) the sleeve 11 and ammunition will remain centrally located in the barrel.

When the ammunition is fired, the crimped or flattened forward end of the sleeve 11 will readily open to allow the ammunition to eject from the barrel. The sleeve 11 is retained in the barrel by the effect of the outwardly projecting lugs in the recess 62 and may be extracted as described for the clip 51.

The sleeve is preferably of thin metal, such as brass cartridge case material, that is readily and easily deformed into the required crimped or flattened configuration. Crimping or flattening, if done at loading, can be by hand or using a suitable tool.

It will be apparent that the embodiment of Figure 11 allows for a greater degree of crimping or flattening at the front end B of the sleeve 11 than at the rear end A, particularly if fewer augmenting charges are employed and that accordingly the crimped or flattened front end B may play a greater role in ensuring that the ammunition will not slide forward.

An advantage of the embodiment of Figure 11 is that the sleeve 11 protects the augmenting propellant charges 84 from the barrel which may become hot when in sustained fire mode. Also the means for positive location of the round of ammunition within the barrel operates to locate the ammunition in the same position against both forward and backward movement within the barrel.

Claims

1. A mortar weapon for firing breech loaded mortar ammunition rounds (80), having a barrel (22) and including a breech, assembly (10) through which the ammunition is loaded into the barrel, breech closing means 14 for closing the breech, ammunition propellant charge firing means which in operation act via the breech assembly to ignite the ammunition propellant charge, characterised by means for the positive location, prior to firing, of the ammunition within the barrel relative to the ammunition propellant charge firing means.

2. A mortar weapon as claimed in Claim 1 characterised in that the means for positive location of the ammunition within the barrel includes a member (51; 11; 90) associated with the ammunition which cooperates with the barrel for positive location of ammunition against forward motion.

3. A mortar weapon as claimed in Claim 2 characterised by a recess (62) in the barrel at the end adjacent to the breech assembly, with which recess the said member cooperates.

4. A mortar weapon as claimed in Claim 3 characterised in that the member (51; 90) associated with the ammunition includes a plate (53; 90) mounted in a plane substantially perpendicular to the longitudinal access of the ammunition, having an outer surface at least part of which surface cooperates with the recess.

5. A mortar weapon as claimed in either Claims 3 or 4 in which the mortar ammunition has a rear assembly and characterised in that the said member (90) is disc shaped and of combustible material adapted to fit over the rear assembly of the ammunition.

6. A mortar weapon as - claimed in any of the preceding Claims characterised in that the member associated with the ammunition is of impregnated cardboard.

7. A mortar weapon as claimed in Claim 4, in which the ammunition has a rear assembly which includes a fin arrangement (82), characterised in that the said member comprises a clip (51) of which the plate (53) Is a part, and having a plurality of projections (57) mounted in a plane substantially perpendicular to the plane of the plate, and which are adapted to cooperate with and fit in positive engagement with the fin arrangement (82).

8. A mortar weapon as claimed in Claim 7 characterised in that the fin arrangement (82) has a central shaft (75) on which are located shallow holes adapted to engage corresponding shallow studs positioned along the length of one or more of tne projections (57).

9. A mortar weapon as claimed in Claim 7 characterised in that the projections (57) have inwardly shaped end pieces remote from the plate (53) which are adapted to clip over the forward end of the fin arrangement.

10. A mortar weapon as claimed in Claims 2 or 3 in which the ammunition has a rear assembly, characterised in that the member associated with the ammunition comprises a longitudinal sleeve (11) initially of circular cross section adapted to fit within the barrel and over the rear assembly of the ammunition, the ends of which sleeve are adapted to be readily deformable into an ovoid cross section shape to hold the ammunition in the sleeve against longitudinal movement and to produce an interference fit of the sleeve in the barrel to hold the sleeve in the barrel.

11. A mortar weapon as claimed in Claim 10 characterised in that the forward and rear ends of the sleeve (11) are adapted to be readily deformable into ovoid shapes, the longitudinal axis of which are perpendicular.

12. A mortar weapon as claimed in Claims 10 or 11 in which the rear assembly includes a fin arrangement (82), characterised in that the end of the sleeve (11 ) adjacent to the fin arrangement has a plurality of radially outwardly projecting lugs (13) which are adapted to cooperate with the recess (62) to prevent forward movement of the sleeve within the barrel.

13. A mortar weapon as claimed in any one of Claims 10, 11 or 12 in which the rear assembly includes a fin arrangement (82) characterised in that the end of the sleeve (11 ) adjacent to the fin arrangement has a plurality of radially inwardly projecting lugs ( 15) which act as a stop against which the fin arrangement of the ammunition abuts to prevent backward movement of the ammunition out of the sleeve.

14. A mortar weapon as claimed in any of the Claims 10-13 characterised in that the tail assembly of the ammunition has means for positioning augmenting propellant charges on the ammunition, characterised in that the sleeve (11 ) is of sufficient length and is adapted in use to fit over the fin arrangement and augmenting propellant charges.

15. A member associated with a round of mortar ammunition (80) for positively locating the round of ammunition in the barrel (11 ) of the mortar weapon as claimed in either Claims 5 or 6.

16. A member associated with with the round of mortar ammunition for positively locating the round of ammunition in the barrel (11 ) of the mortar weapon as claimed in any of Claims 7, 8 or 9.

17. A member associated with the round of mortar of ammunition (80) for positively locating the round of ammunition in the barrel (11) of the mortar as claimed in either Claims 10, 11 or 12.

18. A mortar weapon as claimed in any of the previous Claims characterised in that the means for positive location of the round of ammunition acts to prevent backward movement of the ammunition, and comprises detent latch means associated with the breech means.

19. A mortar weapon as claimed in Claim 18 wherein the detent latch means comprises an arm portion which is resiliently biased towards a generally radial direction relative to the axis of the breech means.

20. A mortar weapon as claimed in Claim 19 wherein the latch means are located in recesses formed in thread interruptions in the breech means and have arm portions which are depressed into said recesses by the action of loading a round of ammunition or bringing the breech closing means into engagement with the breech means.

21. A mortar weapon as claimed in Claim 20 wherein the arm portion is resiliently biased so as to return to a radially directed position relative to the axis of the breech means after being traversed by a round of ammunition.

22. A mortar weapon substantially as hereinbefore described with reference to the accompanying description and Figures 1 to 5D; 6A to 6D; 7A and 7B; 9A, 9B to 10A, 10B; and/or Figure 11 of the drawings.