Device for firing practice ammunition

A weapon for firing practice ammunition includes a barrel having a frontal length portion terminating in a muzzle; an ammunition loading chamber at a barrel end opposite the muzzle; and a plurality of first gas outlet bores provided in the frontal length portion. The first gas outlet bores are arranged in a plurality of circumferentially spaced axial rows. There is further provided a muzzle brake sleeve coaxially surrounding the frontal length portion and having a frontal end situated close to the muzzle. The muzzle brake sleeve includes a plurality of second gas outlet bores arranged in a plurality of circumferentially spaced axial rows. The first gas outlet bores are staggered with respect to the second gas outlet bores as viewed along the barrel. The frontal end of the muzzle brake sleeve is closed off by a plug.

BACKGROUND OF THE INVENTION 
This invention relates to a device for firing practice ammunition 
(projectile-less cartridges). The device includes a weapon barrel or 
weapon tube which, at its end opposite the muzzle, has a loading chamber 
and, at its muzzle, has a frontally closed muzzle brake provided with 
lateral outlet bores. The device may further have a gas-deflecting 
assembly for the recoil of the barrel caused by the exiting propellant 
gases. 
A device of the above-outlined type for an automatic tube weapon is 
disclosed, for example, in German Offenlegungsschrift (application 
published without examination) 37 14 867 which utilizes practice 
ammunition having no projectiles. In this construction a muzzle brake-like 
attachment is screwed on the muzzle of the weapon tube. The attachment has 
an adjustable gas piston for controlling the progression of gas pressure 
and muzzle sound. The gases exit laterally through bores arranged in a 
radial plane. In such a construction there are risks of injury by 
propellant gases and solid particles such as metal, powder or plastic 
fragments because the braking that can be achieved by the deflection and 
the pressure decay is insufficient. Residual particles result from 
stresses on the cartridge tip upon introduction into the loading chamber 
or upon opening of the cartridge tip under gas pressure. Even if a gas 
deflecting ring is arranged on the attachment externally thereof to 
reinforce the recoil of the weapon tube, the above-outlined safety risk 
persists. 
SUMMARY OF THE INVENTION 
It is an object of the invention to provide a firing device for practice 
ammunition of the above-outlined type from which any safety risk in the 
zone of the muzzle is eliminated. 
This object and others to become apparent as the specification progresses, 
are accomplished by the invention, according to which, briefly stated, the 
weapon for firing practice ammunition includes a barrel having a frontal 
length portion terminating in a muzzle; an ammunition loading chamber at a 
barrel end opposite the muzzle; and a plurality of first gas outlet bores 
provided in the frontal length portion. The first gas outlet bores are 
arranged in a plurality of circumferentially spaced axial rows. There is 
further provided a muzzle brake sleeve coaxially surrounding the frontal 
length portion and having a frontal end situated close to the muzzle. The 
muzzle brake sleeve includes a plurality of second gas outlet bores 
arranged in a plurality of circumferentially spaced axial rows. The first 
gas outlet bores are staggered with respect to the second gas outlet bores 
as viewed along the barrel. The frontal end of the muzzle brake sleeve is 
closed off by a plug. 
Thus, according to the invention, the muzzle gas pressure is significantly 
reduced so that solid residual particles--if they leave the barrel at 
all--have no longer a critical kinetic energy so that the danger zone 
around the muzzle is very significantly reduced.

DESCRIPTION OF THE PREFERRED EMBODIMENT 
Turning to FIGS. 1, 2a, 2b and 2c, the practice ammunition firing device 
shown therein includes a rear barrel member 1 and a front barrel member 2 
which are connected to one another by diametrically different threads of a 
threaded member 3 and which together constitute a weapon barrel or weapon 
tube. 
The front barrel member 2 has a muzzle on which there is threadedly mounted 
a muzzle brake (muzzle brake sleeve) 4 which is secured to the front 
barrel member 2 by a locking pin 5 and is closed by a plug 7 which is held 
by a locking pin 6 at the muzzle. The muzzle brake 4 is, adjacent its 
internally threaded portion 8, provided with a plurality of 
circumferentially distributed axial rows of radial outlet bores 9. 
The front barrel member 2 projects into the muzzle brake 4 and terminates 
close to the plug 7. The circumferential wall face of the front barrel 
member 2 is at a clearance from the inner circumferential wall face of the 
muzzle brake 4. The muzzle brake 4 has, in the vicinity of the threaded 
portion 8, an inner land 10 to define a muzzle brake chamber 11 
surrounding the front end portion of the front barrel member 2. 
In the zone of the muzzle brake chamber 11 the front end portion of the 
front barrel member 2 is provided with a plurality of circumferentially 
distributed axial rows of radial outlet bores 12 which are staggered with 
respect to the outlet bores 9 of the muzzle brake 4. 
The threaded member 3 which is secured by means of locking pins 13 and 14 
to the rear and front barrel members 1, 2 has a collar 15 which serves as 
an abutment for the front end of the rear barrel member 1 and the rear end 
of the front barrel member 2. The rear terminus of the threaded member 3 
is provided with a throttle insert 16 which constricts the axial bores 17 
and 18 of the threaded member 3 and that of an insert 19 which is 
adjoining the threaded member 3 and is disposed in the rear barrel member 
1. The insert 19 is rearwardly adjoined by a further insert 22 which has 
at its rear terminus two run-on chamfers 20 arranged at an axial distance 
from one another and surrounding the axial bore 18. 
The threaded member 3 has a smaller inner cross-sectional area than that of 
the front barrel member 2. As a result, upon firing of a practice 
ammunition, there is obtained a substantial, three-step expansion of the 
propellant gases, first in the long front barrel member 2, then through 
the outlet bores 12 (provided in the front barrel member 2) and then 
through the outlet bores 9 (provided in the muzzle brake 4). The outlet 
bores 9 have diameters which are smaller than those of the bores 12. The 
total cross-sectional blowout area of the bores 12 is greater than the 
inner cross-sectional area of the front barrel member 2 in the zone of the 
bores 2; the ratio of these two areas may be, for example, in a range of 
5:1-10:1. By virtue of such arrangement the expansion starts in the front 
barrel member 2 at a large distance from the plug 7. By virtue of multiple 
deflections of the propellant gases, the entrained residual particles may 
be deflected accordingly, so that the latter, if they pass through the 
outlet bores 9 at all, do not have any critical kinetic energy. Because of 
the provision of the plug 7, no propellant gases and residual particles 
leave the weapon barrel through its muzzle. 
The rear barrel member 1 has at its rear part a loading chamber 21 which is 
part of an ammunition supporting chamber that is formed in part directly 
in the rear barrel member 1 and in part in the insert 22 interengaging the 
insert 19. 
In the insert 19, adjacent the throttle insert 16, a plurality of radial 
gas take-out bores 23 are provided, which, through radial gas outlet bores 
34 provided in the rear barrel member 1, maintain communication between 
the axial bore 18 and a plurality of generally axially extending channels 
24 (only one visible in FIG. 2b) provided in a front ring 25 surrounding 
the rear barrel member 1. The channels 24 merge into an annular chamber 
24a which is formed in the front ring 25 and which is also in 
communication with the radial bores 23 of the insert 19. A rear ring 26 is 
mounted on the rear barrel member 1 at a distance from the front ring 25; 
the rear ring 26 is provided with two channels 27, each containing an 
axially extending tubular nozzle 28. The channels 24 and 27 are connected 
by means of respective channels 29 provided in a connecting member 30 
extending between the two rings 25 and 26. The components 23-30 form a 
propellant gas deflecting device. 
Upon firing, the throttle insert 16 causes an accumulation of the 
propellant gases in front of it, as a result of which a corresponding gas 
flow through the gas bores 23 takes place so that the weapon recoil, the 
breech motion and the ammunition advance are ensured in the automatic 
barrel weapon. 
The advantageously replaceable throttle insert 16 which has a fixed 
(constant) flow passage cross section, is made particularly of heavy 
tungsten metal which has superior heat and corrosion-resistance 
properties. By virtue of the proximity of the throttle insert 16 to the 
gas removal bores 23 and because the inner diameters of the inserts 19 and 
22 are significantly less than the caliber of the front barrel member 2, a 
relatively small gas accumulation space is provided. This makes possible 
the use of an advantageous propellant which, for example, may be reduced 
by two-thirds as compared to what is needed for live ammunition. Such 
propellant is fully combusted at smaller pressures which lead to reduced 
stresses on the weapon and the propellant cartridge. The reduced value of 
stress reduction may be, for example, one-fourth of the stresses in case 
live ammunition is fired. This mode of operation provides for an increased 
safety for the personnel in case of malfunction caused, for example, by 
improper handling of the weapon. The throttle insert 16 may be replaced in 
accordance with the requirements of the weapon function. 
The rear insert 22, since it is exchangeably mounted in the rear barrel 
member 1, may be adapted to the ammunition used. Also, in this manner, a 
firing of inadvertently loaded live ammunition is prevented. 
Also referring to FIG. 4, the rear run-on chamfer 20 of the rear insert 22 
is composed of two conically extending annular faces 20a, 20b which are 
axially separated from one another by a cylindrical annular face 20c. The 
cone angle of the annular face 20a is smaller than that of the annular 
face 20b. Thus, the cone angle of the annular face 20a is, for example, in 
a range of 10.degree.-20.degree., preferably in a range of 
17.degree.-18.degree.. The cone angle of the annular face 20b is, for 
example, equal to or larger than 25.degree. and is at most, for example, 
45.degree.. 
Upon loading of the practice ammunition 31, first its bursting body 32 
arrives into engagement with the annular face 20b so that upon continued 
advance of the ammunition the bursting body 32 is pushed into its 
propellant sleeve 33 until the sleeve crimping, opened by the inwardly 
telescoping bursting body 32, arrives into engagement with the annular 
face 20a and is thereby again crimped firmly about the bursting body 32 in 
the vicinity of its frontal conical portion which, for this purpose, has a 
cylindrical zone 34. In this manner, during the subsequent ejection the 
remaining part of the bursting body 32 is securely removed together with 
the sleeve 33. 
A coordination of the weapon function regarding the breech recoil, the belt 
feeder, the weapon recoil, and the cadence height may be achieved by 
coordinating the following parameters: quantity of propellant, combustion 
behavior of the propellant, opening resistance of the cartridge in the 
zone of the cartridge tip (material, strength, wall thickness and 
manufacturing process), the accumulating volume in front of the throttle 
insert 16 (length and diameter of the inner bores in the inserts 19, 22), 
throttle diameter and diameter of the gas removal bores 23. 
It will be understood that the above description of the present invention 
is susceptible to various modifications, changes and adaptations, and the 
same are intended to be comprehended within the meaning and range of 
equivalents of the appended claims.