25mm Ammunition Flashcards

1
Q

Ammunition Natures selected for use with the ASLAV25 Bushmaster M242 Weapon system in service are:

A

Armour Piercing Discarding Sabot with Tracer (APDS T) M791

Target Practice Discarding Sabot Tracer
(TPDS T) M910

Multipurpose with Tracer Self Destruct Mk 2 (MPT SD Mk2)

High Explosive Incendiary Tracer M792

Target Practice with Tracer (TP T) (ADI) M793

Dummy M794

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2
Q

25mm cart case characteristics:

A

Rimless drawn steel painted olive drab / dark green

Projectile secured by either eight bit or single 360 degree indenting

A link locating groove is located below the shoulder

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3
Q

25mm primer characteristics:

A

M115 press fit percussion type

Punch stabbed or ring indented into position

A 10g IB52 booster pellet augments the primer

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4
Q

25mm propellant characteristics:

A

overseas produced ammunition
Approximately 90g of Olin WC890 Ball Powder

local production
single based ADI AR2220 propellant

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5
Q

Ranges of Armour Piercing Discarding Sabot
with Tracer (APDS T) M791

A

Suitable for engaging soft skinned
targets at greater than 1500m

Hard types of cover, such as concrete
structures, at greater than 1000m.

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6
Q

Parts of the Armour Piercing Discarding Sabot with Tracer (APDS T) M791

A

Projectile body consists of:

A solid tungsten alloy penetrator of 12.7mmdiameter

Pressed on aluminium windscreen

Pressed in tracer pellet that burns for a
minimum of 1.4 seconds

Moulded discarding type nylon sabot

Pressed on polyethylene nose cap

Muzzle velocity of the projectile is 1345 m/s

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7
Q

Markings of the 25mm Armour Piercing Discarding Sabot with Tracer (APDS T) M791

A

Projectile / Sabot
Black with white markings

Cart Case
Dark Green / olive drab with
manufacture details and year (last two
digits) stamped into base

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8
Q

25mm Target Practice Discarding Sabot with Tracer (TPDS T) M910 is ballistically matched to which nature?

A

Ballistically matched to Armour Piercing Discarding Sabot with Tracer (APDS T) M791 to 2000m

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9
Q
A

Armour Piercing Discarding Sabot
with Tracer (APDS T) M791

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10
Q

Parts of the Target Practice Discarding Sabot with Tracer (TPDS T) M910

A

Projectile body consists of:

A solid steel core penetrator (sub projectile) encased in a mouldered nylon sabot (aluminium base)

Pressed on Polyethylene Nose Cap

Pressed in tracer pellet that burns for a
minimum of 1.4 seconds

Muzzle velocity of the projectile is 1520 m/s

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11
Q

Functioning of 25mm Target Practice Discarding Sabot with
Tracer (TPDS T) M910

A

Firing pin initiates primer

Which ignites booster pellet & propellant

Gases propel projectile forward simultaneously igniting tracer element

Spin of projectile on barrell exit causes separation of sabot and sub projectile

Sub projectile spin stabilised

High mass flow tracer decreases base drag allowing sub projectile to balistically match to M791 to range of 2000m

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12
Q

Markings Target Practice Discarding Sabot with Tracer (TPDS T) M910

A

Projectile
Blue with white markings

Cart Case
Dark Green / olive drab withmanufacture details and year (last two digits) stamped into base

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13
Q

Parts of a Multipurpose with Tracer
Self Destruct (MPT SD Mk2)

A

The projectile comprises of:

An aluminium nose cap incorporating a support disc and RS38 / RS41 Incendiary Mixture of 2.7g
Nose cap separated from main charge by support disc with 3mm flash channel
Boron steel (strengthened) fully heat treated body
Integral traced/self destruct element (magnesium)

Sintered iron driving band

Main charge consists of:
Press filled incendiary of 9g of RS40
10g high explosive Comp A4

Tracer/self destruct (3 stage) comprising
of:
RS56 Igniter, RS55 Subigniter,& RS42/54 Tracer Composition
Tracer protected with a sealing disc

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14
Q

Functioning of MPT SD Mk2

A

On firing tracer igniter initiated via propellant
gases/heat and projects projectile from barrell

Spin / heat causes RS38 / RS41 mix to change
in consistency

Friction through air heats nose cap critical

On impact nose cap is crushed (threshold
velocity of 250m/s (min) required to initiate
RS38/41mix) critical

Compression of void in nose cap raises temp of RS38/41 to ignition point (approx 500 deg C)

RS38/41 mix ignites and flashes through support disc and:

initiates main fill of RS40 incendiary & Comp A4 HE compositions

causing heat / flame / blast and fragmentation effect at the target

Should target be missed, self destruct is initiated by tracer igniter after 5.3 secs of flight.

NOTE: Delay of 0.3 millisec allows strengthened projectile to penetrate skin of target before detonating creating blast fragmentation & incendiary effects behind or inside target

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15
Q

Self Destruct Function of 25mm MPT SD Mk2

A

At shot start:

Closure disc disrupted

tracer comp ignited

Proceeds to burn in flight

Sufficient heat generated to function Comp A4 filled self destruct well

Normal burn time to self destruct not less than 5.3seconds or 2500m

Self destruct feature eliminates collateral damage following engagement of aerial targets

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16
Q
A

25MM MPT SD Mk 2

17
Q
A

High Explosive Incendiary Tracer (HEI T) M792

18
Q

Describe High Explosive Incendiary
Tracer (HEI T) M792

A

The projectile consists of:

A hollow C1045 steel body
A M758 Mechanical PD Fuze
H761 HEI mix fill
Swaged iron rotating band
Projectile length may vary dependant on the
manufacturer, as a result of varying trace booms.

Main charge consists of:
32g of HEI fill

The Fuze consists of:
Unknown Booster Pellet composition but
maybe PBXN 5

Cart Case consists of:
90g of WC890 propellant
M115 percussion primer

19
Q

25MM HEIT M792

A
20
Q

25MM HEIT M792 Functioning

A

On firing the primer initiates the propellant,
projecting the round at a nominal velocity of
1100m/s

Maximum effective range = 3000m, with a non arming distance of 10m

The flash from the propellant ignites the tracer
ellement

On impact the PD fuse functions and the HEI fill detonates dispersing the incendiary mix

21
Q

25MM HEIT M792 Self Destruct function

A

Self Destruction

In the absence of impact the self destruct function contained in the fuze initiates due to spin decay

The self destruct functions the fuze after a nominal six seconds from firing

22
Q

Target Practice with Tracer (TP T) M793

A

Projectile body consists of:

A hollow steel body
Screw on steel nosepiece
Integral driving band
Crimped to a steel cart case
An integral tracer is pressed into a
recess in the base of the projectile

23
Q

Functioning of Target Practice with Tracer (TP
Practice with Tracer (TP-T) M793

A

When fired, the primer is mechanically
initiated by the weapon firing pin.

The primer then ignites the booster pellet
which in turn ignites the propellant charge.

Projectile is then launched at a velocity of
1100 m/s, achieving a max effective range of
1600 m with tracer visibility to 2000m.

The projectile is inert and on striking a target
the ballistic cap is either crushed or sheared
from the proj body.

24
Q
A

Target Practice with Tracer (TP
Practice with Tracer (TP-T) M793

25
Q

Description of Dummy M794

A

The cartridge is a modified M793 TP T
projectile silver brazed to a modified
standard cart case

The cart case is filled with epoxy resin to
approximate weight of the M793

The threaded nose of the TP T projectile is
silver brazed to the projectile body to
improve physical integrity