GB2163840A

GB2163840A - Pistol

Info

Publication number: GB2163840A
Application number: GB08521309A
Authority: GB
Inventors: Michael Chivers
Original assignee: Australian Government
Current assignee: Australian Government
Priority date: 1984-08-28
Filing date: 1985-08-27
Publication date: 1986-03-05
Also published as: GB8521309D0; DE3530368A1; FR2569831A1; BE903129A

Abstract

A barrel 7 for use with blank ammunition in an automatic firearm of the positively locked type, e.g. a Browning pistol, wherein conventional slide locking lugs on top of the barrel are removed and replaced by a sloping cam surface 13 which abuts the locking lugs 9 of the slide 5 when the barrel 7 is in the ready to fire position. The muzzle of the barrel 7 incorporates a restrictor 14 adapted to increase the internal gas pressure within the barrel following the discharge of the firearm. <IMAGE>

Description

SPECIFICATION Pistol This invention relates to an automatic firearm, e.g.

a self-loading pistol, and to a barrel therefor.

It is conventional practice that self-loading pistols of the recoil operated positively locked type are not able to function in self-loading mode when used with blank ammunition. In the absence of a bullet in the barrel insufficient recoil effect is available to provide the necessary recoil forces to complete the operational cycle which ejects the empty cartridge and places a new cartridge into firing position. Formly in certain self-loading weapons a restriction on the muzzle, such as a choke or gas deflector provides an increase in the gas pressure within the barrel sufficient to provide the necessary recoil forces.However, in an automatic pistol of the Browning type the barrel in its normal position is positively locked against the slide and in such positively locked self-loading pistols the provision of a muzzle restriction has no effect in unlocking the barrel from the slide to initiate the self-loading operation with blank ammunition. The pistol of the general type to which this invention relates is described in U.S. Patent No. 1,618,510.

Thus it is an object of this invention to provide a mechanism which would enable an automatic pistol of the recoil operated positively locked type to be used in its self-loading mode with blank ammunition.

To this end the present invention provides in an automatic firearm of the type having a receiver, a slide travelling in the receiver and a barrel which fits into the slide and is lockable to the slide by interlocking lugs on both the slide and the barrel, the improvement comprising providing a barrel for use with blank ammunition in which the locking lugs on the barrel are eliminated and replaced with a sloping cam face which abuts the locking lugs on the slide and wherein the muzzle of the barrel incorporates a restrictor adapted to increase the internal gas pressure within the barrel following the discharge of the firearm.

As explained above, the provision of a restrictor has been commonly used in other self-loading weapons to provide sufficient gas pressure to ensure that the slide is moved backwards to operate the ejection mechanism and place a new round in the breech.

However, the positive iock characteristic of the weapon for which this invention is intended still prevents the free movement of the barrel which can be achieved when blank ammunition is fired.

By eliminating the locking lugs from the barrel the movement of the barrel is not so restricted. However, it has also been found that in order to ensure that the barrel drops as is described in U.S. Patent No. 1,618,510, it is necessary to provide a sloping face on that portion of the barrel which abuts against the locking lugs.

It has been found that preferably the angle of that face should be the same as the angle of the cam which after the pistol is fired, guides the downward movement of the barrel away from the upper portion of the slide.

A preferred embodiment of this invention will now be described with reference to the drawings.

Figure 1 provides a schematic sectional view of the pistol; Figure 2 provides a side elevation of the barrel of this invention; Figure 3 provides a sectional view of the restrictor; and Figure 4 is a front end view of the restrictor.

Basically the pistol comprises a slide 5, a receiver 6 and a barrel 7. The receiver 6 comprises the hand grip which contains a magazine and has provision to enable the slide to move along the top portion of the receiver to allow the ejection of a fired round and the insertion of a fresh round from the magazine into the breech 8 of the barrel 7.

As in the weapon described in U.S. Patent No.1,618,510, the slide 5 incorporates locking lugs 9 in the slide and the barrel includes the cam surface 10 and the forward lug 11 which are used to guide the barrel downwards to allow the reverse movement of the slide. The lower portion of the cam 10a rests on the pin 12 which is secured to the receiver 6. This portion of the barrel is not modified for the purposes of this invention and functions in tha same manner as the weapon described in U.S. Patent No. 1,618,510.

The cam face 13 of the barrel abuts the shoulder of the last of the locking lugs 9 when the barrel is in the ready to fire position. The angle of the face 13 is equivalent to the angle of the cam face 10 as it has been found that this provides the best result in providing for downward movement of the barrel 7 as the slide 5 moves rearwardly.

The restrictor 14 is shown as a screw insert into the muzzle of the barrel 7 (see Figure 3). The diameter of the hole on the restrictor which is axially aligned with the cylinder of the barrel is of critical importance in providing sufficient internal gas pressure to provide the necessary recoil forces to operate the slide. The size of the orifice 15 in the restrictor is to be determined by calculation which will taken into account the volume of the barrel, the amount of charge in the bullet and the pressure necessary to produce the required recoil action of the slide. Those skilled in the art will be aware of the need for some trial and experimentation to determine the appropriate orifice size for a particular ammunition type.

From the above it can be seen that the present invention provides a replaceable barrel which can be used for standard weapons of the type described in U.S. Patent No. 1,618,510 which will enable the weapon to be used with blank ammunition. In the past, when blank ammunition is used with standard barrel types the weapon did not function as a self-loading weapon and could only fire a single shot and then needed to be hand cocked. Thus, by providing a replaceable barrel the present invention enables standard weapons to be used for training purpose where blank ammunition is preferably used.

Claims

1. An automatic firearm of the type having a receiver, a slide travelling in the receiver and a first barrel which fits into the slide and is lockable to the slide by interlocking lugs on both the slide and the barrel, wherein the firearm is provided with a replacement second barrel for use with blank ammunition having an upper surface which is free of locking lugs and which incorporates a sloping cam face for abutment against one of the locking lugs on the slide and wherein the muzzle of the second barrel incorporates a restrictor adapted to increase the internal gas pressure within the second barrel following the discharge of the firearm when fitted with the second barrel.

2. A barrel for use with blank ammunition in an automatic firearm of the recoil operated positively locked type having a receiver and a barrel receiving slide travelling in the receiver and provided with barrel locking lug means, wherein said barrel comprises an upper surface which is free of lug means for interlocking with the lug means on the slide and which incorporates a sloping cam face for abutment against the barrel locking lug means on the slide and a muzzle incorporating a restrictor adapted to increase the internal gas pressure within said barrel following the discharge of the firearm.

3. A barrel according to claim 2, comprising a cam slot for cooperation with a fixed pin of the firearm, the cam slot and the said cam face being disposed at substantially the same angle to the longitudinal axis of the barrel.

4. A barrel constructed and arranged substantially as herein described with reference to, and as illustrated in, Figures 1 to 4 of the accompanying drawings.

5. A firearm fitted with a barrel as claimed in any of claims 2 to 4.

6. In an automatic firearm of the type having a receiver, a slide travelling in the receiver and a barrel which fits into the slide and is lockable to the slide by interlocking lugs on both the slide and the barrel, the improvement comprising providing a barrel for use with blank ammunition in which the locking lugs on the barrel are eliminated and replaced with a sloping cam face which abuts the locking lugs on the slide and wherein the muzzle of the barrel incorporates a restrictor adapted to increase the internal gas pressure within the barrel following the discharge of the firearm.

7. A barrel for use with blank ammunition in an automatic firearm of the recoil operated positively locked type having a receiver, a slide travelling in the receiver and a barrel which fits into the slide and is lockable to the slide by interlocking lugs on the slide and the barrel, wherein said barrel comprises an upper surface which is free of locking lugs and incorporates a sloping cam face which abuts the locking lugs on the slide and a muzzle incorporating a restrictor adapted to increase the internai gas pressure within the barrel following the discharge of the firearm.