increase in effectiveness of small-arms ammunition · in general the effectiveness of small arms...

WWW.STILETTO.UK.COM

INCREASE IN EFFECTIVENESS

OF SMALL-ARMS AMMUNITION

9x19 mm Luger

INCREASE IN EFFECTIVENESS

OF SMALL-ARMS AMMUNITION

Performance improvements to weapons systems are driven by the need for

Increased accuracy and precision, a decrease in the number of errors while

preparing to fire and an increase in projectile penetration capability.

Improvements in ballistic armour (armoured/bullet-proof jackets) have led to

the gradual decrease in the effectiveness of small arms to incapacitate threats.

In general the effectiveness of small arms ammunition depends on the

armour-piercing core of ammunition: the quality of core material, its form

and importantly the kinetic energy being delivered.

This article analyses issues regarding the enhancement of projectile

penetration by means of increasing projectile initial speed.

www.stiletto.uk.com 1

INTRODUCTION

RESEARCH


Fig. 1. Design of the

Improved Bullet [6].

nozzle

cavity for gun charge

Different techniques available and capable of increasing the initial speed of

projectiles are known. This article analyses one of these techniques, increasing the

boosting pressure without modification of propellant or ammunition structure.

In the course of research it has been revealed that due to ammunition structures,

projectile initial speed may be increased by the motion of propellant gases coming

from the projectiles charge chamber into an after-projectile channel space at the

moment of firing. This means that a rocket gas-dynamic effect is available.

The operating principle of the improved projectile is identical to existing projectiles

except for the fact that it is does not fragment and in the process of burning the

propellant, impinging gases flow through a hole in the nozzle block and creates

propulsive burn numerically equal to the product of speed of gas discharge by their

weight. Due to this, the projectile receives additional impulse to the initial speed in

comparison to existing projectiles.

To better understand the effect emerging, we are going to analyze the simplified

system of differential equations of internal ballistics, which looks as follows:


where

- I means impinging gases pressure pulse,

- t means time,

- P means pressure of impinging gases,

- θ means indicators of adiabatic of combustion products,

- f means force of powder,

- ω means weight of powder,

- Ψ means powder burning function,

- φ means fictitiousness coefficient which takes into

consideration all secondary operations except

for the operation on movement of the propellant charge,

- m means bullet weight,

- V means bullet current speed,

- S means bullet cross-section area,

- LΨ means function of the length of the charge chamber,

- L means current path travelled by the bullet,

- P0 means boosting pressure.

пппп

о

пппп

н

м

по

пн

м

-ЧЧ

Ј

==

+Ч

ЧЧ-

ЧЧ

Ч==

т тt t

dtPPdtm

S

PPесли

Vdt

dL

LLS

Vmf

Pdt

dI

0 0

0

0

2

)(

......0

)(2

j

j

q

fw

qf

,

(1)

However, as it is proved in practice, such measures do not lead to the significant

increase in the initial speed of the projectile.

As seen in (1) mathematical equation, which describes the main task of internal

ballistics, the equation does not take into account the motion energy of

propellant (powder) gases inside the bore at the moment of firing. In the

projectile scheme offered (Fig. 1), as was already mentioned, the propellant

charge is located directly in the projectile. In the process of burning propellant

gases the flow to the after-projectile space of the bore through the rear

calibrated orifice takes place. Due to this, jet propulsion emerges. Consequently

it is fair if the relevant adjustment is made to the mathematical model examining

internal ballistics.

For this purpose, we are going to consider the formula of gas-dynamic forces

acting on the projectile according t:

g

GVPSF газ Ч+Ч= .1

(2)

Where

- F means gas-dynamic force acting on a bullet;

- P1 means pressure on a bullet;

- Vgas means speed of flow of gas from the

bullet nozzle;

- G means rate of flow of combustion products

from the nozzle block of the bullet;

- g means gravity acceleration.


We are multiplying the right and the left parts of the equation (4)

by the time of action of this force t. The result is as follows:

But this is the equation of the quantity of bullet motion under the

action of gas-dynamic force. Then for this case, we are going to

modify some factors (multipliers):

After substitution, the formula (2) looks as follows:

In the result, we have received the equation of the quantity of bullet

motion which is different from the classic formula by the reactive

(jet/rocket) component:

Now, since propellant charge in experimental cartridges is in the

bullet charge chamber, and as it burns, it leaves it, the bullet weight

(weight of the propellant/powder charge is added to the bullet weight)

is a variable depending on the function of powder burning:

g

tGVgastPStF

ЧЧ+ЧЧ=Ч .1

(3)

jЧЧ=Ч mVtF , and т т-=Чt t

dtPPdttP0 0

01 and fw Ч=Ч

g

tG ,

(4)fwj ЧЧ+-Ч=ЧЧ т т газ

t t

VdtPPdtSmV0 0

0 )( ,

fw ЧЧgasV .

)1(__ fwfww -Ч+=Ч-+= mmweightbulletfull . (5)


Consequently taking into consideration above mentioned, after simple

conversions, the formula (4) looks finally as follows:

And identically

Finally, equation of the main task of internal ballistics will look as follows:

Now, we are going to make final calculations based on the new mathematical f

ormula and compare calculations with the experimental data. Before this, we

are going to set parameters for boosting pressure and the coefficient of

fictitiousness for the projectile. The speed of gas flow from the projectile

charge chamber into the after-projectile space bore will be taken as equal

to the speed of projectile.

(6)

(7)

(8)

[ ])1(

)(0 0

0

fwj

fw

-Ч+Ч

ЧЧ+-Ч

=т т

m

VdtPPdtS

Vгаз

t t

[ ]

)(2

)1( 2

LLS

Vmf

P+Ч

Ч-Ч+Ч-

ЧЧ

Ч=f

fwj

q

fw

q

[ ]

[ ]пппп

о

пппп

н

м

пп

о

пп

н

м

-Ч+Ч

ЧЧ+-Ч

Ј

==

+Ч

Ч-Ч+Ч-

ЧЧ

Ч==

т т

)1(

)(

......0

)(2

)1(

0 0

0

0

2

fwj

fw

fwj

q

fw

qf

m

VdtPPdtS

PPесли

Vdt

dL

LLS

Vmf

Pdt

dI

газ

t t


Boosting pressure.

Since the sub-calibre projectile does not run into the main bore in our case, the

gripping force is unavailable. Therefore, boosting pressure will work on ejection

of the projectile from the cartridge case (jacket). Mean statistical gripping force

of the projectiles from cartridge casing is equal to 220 kgs. If we consider the

projectile under the action of propellant gases is squeezed in the case by its ring,

and the width of the ring squeezing is known and knowing the coefficient of

friction of the ring against the case (according to the coefficient of friction of

cadmium-plated projectile against the steel case f = 0,096 ~ 0,1), it is possible

to calculate the value of the force required to get the projectile moving.

Knowing these values we can produce the following equation:

After putting the values into the formula (9), we receive P0 = 901,64 kgs/cm2.

)( 21

0fSS

FP

Ч-= (9)

where

- F means force of ejection of the bullet

from the case (220 kgs);

- S1 means working cross-section area of

the bullet (with the internal diameter of the c

harge chamber of 8,4 mm - S1 ~ 0,554 cm2);

- S2 means external are of the bullet ring,

by which it is squeezed to the case (with

the bullet diameter of 9 mm and width of the

squeezing component of 11 mm - S2 ~ 3,1 cm2);

- F means friction coefficient ~ 0,1.


Mark on the projectile from the main bore

Fig. 2. Comparative picture of the projectiles (normal projectile is on the left,

Stiletto projectile is on the right) with the marks from the main bore.

Coefficient of fictitiousness.

Since it is not fully known how to calculate the fictitiousness coefficient for

the new projectile design, in our calculations we will take it as equal to

the operating projectile.

After calculations, we have the following outcome:

(6)

(7)

Mark on the Bullet from the Main Bore

L = 11 mm


Fig. 3. Chart showing dependence of the pressure in the bottom of the case

upon the burst time with the experimental cartridge according to the modified

mathematical model.

Fig. 4. Chart showing dependence of the projectile speed along the length

of the bore at the time of firing according to the modified mathematical model.

0 5 .104

0.001 0.0015 0.002 0.0025 0.003 0.0035 0.0040

500

1000

1500

2000

2500Ãðàôèê äàâëåí èÿ ï î ðî õî âûõ ãàçî â

Âðåì ÿ (ñ)

Äàâë

åíèå

ïî

ðîõîâû

õãàç

îâ

(êãñ/

ñì

^2

)

2.467 103

ґ

59.313

Päóë

4 103-

ґ4.365 104-

ґt1 r

0 0.02 0.04 0.06 0.08 0.1 0.120

100

200

300

400

500

600Ãðàôèê ñêî ðî ñòè ñí àðÿäà ï î äëèí å ñòâî ëà.

Äëèí à ñòâî ëà (ì )

Ñê

îðîñ

òüñí

àðÿä

à(ì

/ñ)

510.678

0

Vvvv

0.1060.013 Lñò

pow

der

gas

pre

ssure

kgf/cm

2

time

pro

ject

ile v

elo

city

(m

/ s

)

Barrel Length (m)


It is seen from the calculations that due to such a scheme of ammunition

design the projectile must have high initial speed in comparison with the

projectiles of identical cartridges.

Practical firing has demonstrated the following results.

Cartridges with Stiletto projectiles have preliminary undergone comparative

testing in the Laboratory of Criminal Expert Examination at the State Scientific

and Expert Criminal Research Centre of the Ministry of Internal Affairs of the

Ukraine, in the city of Vinnytsia and the Lugansk Cartridge Plant. Based on

the approved methodology of enterprises, the following measurements

were made:

-Projectile initial speed;

-Free blowback energy;

-Maximum pressure in the bore at the time of firing.

At the same time, the following mean values have been received (Table 1):

As it is seen from Table 2, theoretical calculations coincide with the

data of practical firing.

Table 1. Type of cartridge

Type ofweapon

Mean bullet initial speed

(m/sec)

Free blowback energy

(J)

Maximum pressure in the

bore (kgs cm2)

9,0 mm Пст гс Gun “PM” 317 3,67 - 9,0 mm Пст гс Gun“FORT” 316 3,36 - 9,0 x 18 mm experimental

upgarded

Gun “PM” 514 4,8 2439

Table 2.

Type of cartridge

Measured bullet initial speed

(m/sec)

Calculated bullet initial

speed (m/sec)

Measured maximum

pressure in the bore

(kgs cm2)

Calculated maximum

pressure in the bore

(kgs cm2 9,0 x 18 mm experimental

514

510,678

2439

2467


The result of increased projectile initial speed due to energy flow of propellant

gas from the charge chamber into the after-projectile space of the bore,

has increased projectile penetration of the new projectile in comparison with

existing projectiles [6].

The new design (Fig. 1) ensures penetration at the distance of 25 meters of steel

plate (Ст. 3) 7 mm wide (Fig. 6) which is an analogue of the ballistic protection

of 4nd class protection armoured jacket [16].

1 2 3

4 5 6 Fig. 5. Target steel plate after conducting the experiment.


1, 4, 6 are imprints received after firing from a «ТТ» gun with the standard

operating cartridge (projectile with the steel core);

2 is the imprint received after firing from a P – 38 «Walter» gun with

the standard operating cartridge (projectile with the steel core);

3 is penetration from a «Makarov» gun with the experimental cartridge;

5 is an imprint received after firing from gun «Makarov» with the

standard operating cartridge (projectile with the steel core).


Entrance hole.

Exit hole.

Penetration of hardened steel plate 7 mm at distance of 25 мeters


Penetration of hardened steel plate 7 mm at distance of 25 мeters

Entrance hole.

Exit hole.


CONCLUSION

As the result of research performed, it is determined that it is possible to

control the flow of propellant gases in the bore. In the process of such flow

reactive (jet) components emerge, which significantly increases the initial

speed of the projectile.

Use of this new design allows making of ammunition with enhanced fighting

power for existing types of small arms.

increase in effectiveness of small-arms ammunition · in general the effectiveness of small arms...

Documents