LO4 - Cartridges and Projectiles Flashcards
1
Q
What are different way to compensate spin in shape charge rounds?
A
- Slipping driving bands
Carl Gustav 84 mm HEAT round - Fluted liners
Attack Helicopter 30 mm HEDP round - Spin compensated liners
2
Q
What are the factors affecting performance of HESH rounds?
A
- Calibre
thickness of plate defeated is proportional to the calibre - Angle of Attack
limited to the angle at which ricochets start
around 65 degrees
functioning can be expected up to 60 deg. - Striking velocity
too much velocity and the projectile may malfunction due to impact initiation
shock detonation
3
Q
What are the different types of natural fibres?
A
- Cellulose
- Silk
- Wool
- Rubber
4
Q
What are the 2 differnt types of plastic and the main difference between them?
A
- Thermoplastic - Thermo Plastic can be reheated and reshaped
- Thermosetting plastic - is incapable of again being softened by heat
5
Q
What is used for non-permanent seals?
A
Luting
6
Q
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What are the different types of defects?
A
- Mechanical
Cracking due to stress - Chemical
Corrosion due to impurities
7
Q
What is Annealing?
A
- Relief of work stresses i.e. annealing makes larger crystals at neck softer
- Often performed on cartridge neck after forming
8
Q
Define corrosion.
A
The conversion of metal to a non-metallic state
9
Q
Types of corrosion.
A
- Rust (Ferrous Oxide) - Most common type affects projectiles
- Aluminum Oxidation - Tail fin assemblies (mortar)
- Cupric Azide contamination
- Zinc exudation/ ‘Free copper’
- MAZAK contamination - Magnesium + Aluminium + Zinc + Copper
10
Q
What is the charge to weight ratio (CWR) in modern HE?
A
20 to 30%
11
Q
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What are the different filling techniques?
A
- Casting
Straight pour
Creamed
Liquid and biscuit - Pressing
Pressing (e.g. F1 grenade)
Incremantally into case
Pre-pressed charges - Extruding
Direct extrusion into case - Pre-forming/ cocooning
Land mines
12
Q
What are the disadvantages when casting using hot melt process?
A
- Shrinkage
- Cracking
- Dusting
13
Q
What are the principle requirements of tracer
composition?
A
- Luminosity
- Strength
- Consistency of Performance
- Ease of Ignition
14
Q
What are the classification of tracers?
A
- Tracer Projectile
- Tracer and Igniter Projectile
- Integral Tracer
15
Q
What are the means of igniting tracer?
A
- Direct ignition
- Propellant ignition
16
Q
What are the types of primers?
A
- Percussion
- Electric
Bridge wire,
Conducting cap
17
Q
What are the design features of a primer?
A
- Produce Sufficient Flash to ignite the propellant
- Pass the flash evenly over the propellant
- Be self obturating, externally and internally
- Protect the Gunpowder & propellant from moisture
- Flush fitting Screwed / Press fit
18
Q
Components of a primer and explanation?
A
- Body
Contains all the other components - Cap
Holds initiating composition - Anvil
Shaped metal component located above the Cap.
Provides the resistance to the crushing action of the Striker which cause the composition to ignite.
Has flash holes for the passage of flash.
Contains seating for internal obturating device. - Plug
Provides fire channel through which the flash passes to the magazine.
Retains cone/ball of sealing device. - Magazine
May be a recess in body or separate cylinder
19
Q
Types of obturating systems
A
- Cap Holder
- Ball in Cone Seating
- Cone in Cone Seating
- Firing Plug and Bty Cap
20
Q
Components of bridge wire electric primer?
BBCM
A
- Base
Screw threaded externally to engage in the base of the cart case
Interior is bored & screwed threaded to take an Ebonite Cup, contains the contact piece & bridge wire
Recess is formed in body to hold small QTY guncotton dust around the bridge & gunpowder pellet above it
Forward end of body is screw threaded to accept the Magazine - Contact piece
The initial Contact which is housed in the Ebonite Cup - Bridge
Consists of a short length of iridio platinum wire, both ends of which are secured to the Bridge plug
One end is attached to a copper wire running down the insulated centre of the body to a contact piece
The other to an earthed pole - Magazine
Separate cylindrical brass container. Holds GP
21
Q
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Components of conducting cap electric primer?
BPCM
A
- Base
Screw threaded externally to engage in the base of the cart case
Remainder of body screw threaded on a reduced diameter for attachment of the magazine
Interior is bored & screwed threaded at the rear to house a Plastic Insulating Cup, containing a Brass contact piece & Pole Unit
Forward portion of Body recessed & screw threaded to accommodate a conducting Cap & a Closing Plug - Pole unit
Brass Pole, tapered towards the rear which has a plastic insulating sleeve moulded to it
Drilled at the forward end to house a small Phosphor Bronze Spring , which ensure continuity of the Circuit between the conducting cap-pole - Cap
Incorporates a brass pole piece which is insulated and surrounded by conducting cap composition - Magazine
Separate cylindrical brass container. Holds GP
22
Q
Definitions of round, projectile and component.
A
ROUND
A complete assembly of a projectile (with or without fuze), a propellant charge in a cartridge case, and the means of igniting
the propellant charge.
PROJECTILE
An object capable of being propelled by a force, normally from a gun, and continuing in motion by virtue of its kinetic energy
COMPONENT
An item which is an integral part of a system, sub–system or stem or equipment
23
Q
Types of projectile
A
- Shot
- Shell
- Carrier
24
Q
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Different parts of projectile
A
- Body
- Head
- Shoulder
- Driving band
- Ogive
- Band (Bourrelet)
- Band
- Base
- Wall
- Cavity
- Lip
- Fuze hole
- Governing section
25
Classification of projectiles
* Operational Projectiles
Shot (KE)
Shell --effect produced by payload
Mortar
Grenade
Bullet
* Weapon Functioning / inspection
Bulleted Blank (SAA)
Paper shot (Weapon test)
Proof
Gun functioning
* Training Projectiles
Practice
Drill/Dummy
Instructional
Break--up
Sub--cal
26
Define projectile
An object capable of being propelled by a force, normally from a gun, and continuing in motion by virtue of its kinetic energy.
27
Types of KE projectiles?
* Armour Piercing (AP)
* Armour Piercing Capped (APC)
* Windshield
* Penetrative Cap
* Ballistic Cap
* Armour Piercing Capped Ballistic Capped (APCBC)
* Armour Piercing Discarding Sabot (APDS)
* Semi Armour Piercing (SAP)
* Armour Piercing Fin Stabilisedised Discarding Sabot (APFSDS)
28
# REMEMBER THIS QUESTION
What is the function of driving band on a projectile?
* To centre projectile in bore and impart spin
* To prevent the forward escape of propellant gases
* To assist in prevention of slipback of the projectile when loaded at high elevations
29
# REMEMBER THIS QUESTION
What are the requirements of driving band?
* No excessive pressure on the shell or barrel
* Cater for change in bore diameter (wear)
* Remain firmly attached to the projectile
* Must not alter the ballistic shape of the projectile (engraved state)
* Cause no excessive friction or bore wear
* Simple to make and fit
30
Requirements of driving band material
* The metal used must be soft, to give the least wear possible in the gun
* Must not be so soft as to strip under the rotational and engraving process in the bore
* Copper has been found to be the best
31
What re the methods of attachement for driving bands?
* Split Ring
A strip is cut to the required length, formed into a ring, ends butted together
pressed onto shell by a multi--ram press
* Solid Ring
A ring of the correct width is cut from a length of seamless copper tube
slipped over the shell
pressed in the same method as for split ring method
32
Methods to prevent twist of driving band from projectile
* Wavy rib
* Knurling
33
What are the types of driving bands?
* Orthodox
* Modern band
* Double band
* Gas check type
* Probert
34
what are the requirements of slipping ring?
* Should breakup on leaving the barrel
* Should breakup into particles small enough so as not to harm friendly troops
* chances of any fragments remaining in the barrel should be minimal
* the ring should still engage the rifling and not soften under bore temperature
35
What are slipping rings used for?
Slipping rings are designed to ensure that the spin imparted by the weapons barrel does not reach a rate that would influence the fin stabilisation of a projectile or would reduce the effectiveness of a hollow charge
In simple words, it controls the spin of a projectile inside barrel to not affect the final effect
36
# REMEMBER THIS QUESTION
Advantages of breech loading system?
* Less stowage problems / reduced length
* No Cart Case
37
# REMEMBER THIS QUESTION
Disadvantages of breech loading system?
* Slow loading process
* Slow rate of fire
* Three components = slow process
38
What are the components that make up the Quick Firing system?
* Cart Case with Primer
* Propelling Charge (can be Charge Bags )
* Projectile
39
What are the different types of Quick Firing (QF) systems?
* QF Separate
* QF Semi-fixed
* QF Fixed
40
# REMEMBER THIS QUESTION
What are the two types of systems?
* Breech Loading (BL)
* Quick Firing (QF)
41
# REMEMBER THIS QUESTION
What are the components of BL system?
* Tubes / Primers
* Bagged Charge
* Projectile
42
What are the advantages of QF Separate / Semi--fixed over QF Fixed?
* Adjustable charge
* Can replace damaged Cart Case
* Less stowage problems due to reduced length
43
What the different types of QF propelling charges?
* Fixed
* Semi-fixed
* Separate
44
Factors affecting the choice of fixed ammunition.
* Fixed charge weight (direct fire)
* High rate of fire / automatic loading
* All up weight and size of round should not make handling difficult
45
4 Types of bagged charges?
* Equal
* Unequal
* Stem and Ring
* Stem and Segment
46
Design considerations of bagged charges.
* Be non-smolder
* Be non-stretch
* Be non-wear
* Be entirely consumed on firing.
* Leave no smouldering particles or residue.
* Be insect / vermin / rot proof
* Be permeable to the flash from the tube
47
What are the materials used for charge bag materials?
* Silk (in old times)
* Terylene/ cotton material (modern day)
48
What is de-coppering?
The process of cleaning the bore of the weapon of copper deposits left by the driving band.
49
What are the different types of charge bags
* Normal
* Super
* Reduced
* Fractional
* Incremental
* Blank charge
* De-coppering charge
50
What is the difference between combustible and consumable cartridge cases
* Consumable - Material that is used up during the process of the combustion of the propellant. It is an inert material and does not contribute to the explosive process.
* Combustible - Material that is capable of burning and contains ingredients that contribute significantly to the production of propellant gasses.
51
# REMEMBER THIS QUESTION
Advantages of combustible cartridge cases?
* No spent cart case to be collected or extracted
* Less fumes
* Ammunition weight is less.
* Easier to adjust charge.
* Reduced barrel wear.
* No cluttering at the gun site.
52
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Disadvantages of combustible cartridge cases?
* Lack of strength
* Residue left.
* Additional components to load.
* Chance for a "cook off".
* Ingress of moisture.
* New propellant had to be developed which was insensitive to sparks & static - High Ignition Temp Propellant (HITP)
53
2 types of systems for liquid monopropellant.
* Regenerative system
* Travelling Charge Injection system
54
Two types of RCL ammunition design
* Solid Cart Case with blow out rear disc
* Perforated cart case system
55
Advantages of RCL systems
* No Recoil
* Low Weight
* Man Portable
* can be mounted on Light Vehicles
56
Disadvantages of RCL systems
* Flash / Dust signature (BBDA)
* Low Velocity
* Large Propelling Charge
57
Explain the method of operation of the solid cart case with blow out disc.
Propellant charge initiated, pressure builds up, blow out disc ruptures, the projectile is propelled forward and the propellant gases escape through the rear breech hole and out through the venturi.
58
Explain the method of operation of the perforated Cart case
* On firing – Prop charge initiated
* sheath ruptures allowing prop gases to escape through holes in cart case, into annular space, out through venturi
* Pre-rifled projectiles are used to alleviate pressure build up
59
Propelling charges are generally made up of
3 distinct components?
* Charge container
* Propellant
* Initiator
60
Materials used in cart cases?
Brass is used as the standard, 70/30 copper
(Cu) / Zinc (Zn)
61
3 methods used to attach projectiles to cartridge case
* Coning
* Canneluring
* Coning and Canneluring
62
Define coning and canneluring
Coning - The mouth of the cartridge case is turned into a groove or cannelure situated around the base of the projectile, just below the driving band.
Canneluring requires the pressing of the mouth of the case into a groove or cannelure, near the base of the projectile. Canneluring can be spaced or continuous.
63
Methods of Filling cart cases
* Loaded directly or into charge bag or bags
* Charge bags used in multi – charge systems
* Charge bag may be used where charge weight is small in relation to the volume of the case
64
# REMEMBER THIS QUESTION
Advantages and disadvantages of Combustible Cart Cases (CCC)
Advantage of CCC
* Everything loaded into the chamber plays some part in ballistics
Disadvantage of CCC
* Lower charges of a multi charge system that a disproportionate amount of cloth is loaded
* At low pressures there is a danger of incomplete combustion
65
What are the factors that affect shell design?
(SUBSET)
* Target effect
* Ballistic performance
* Strength to withstand firing stresses
* Economy in manufacture
* User requirements
* Safe handling ,transportation and storage
66
What are different target effects?
* Physical
Casualties to person
Damage to materials
* Psychological
Neutralisation
Demoralisation
* Blast
* Fragments
67
What are the forces acting on a projectile?
* Gas pressure - 800m/s
* Acceleration - 5800g
* Setback
* Heat
* Centrifugal
* Driving band pressures
* Side slap - Hoop stress/shear stress
* Drag
68
Where is the ideal position of driving band?
* Far to rear as possible
* Forward of the streamlining
* Fixed ammunition forward
69
Military requirements for projectiles
* Withstand rough usage
* Capable of storage in varied climates
* Have little in-service maintenance
70
How is nose and base drag reduced?
* Nose drag is reduced by head shape (Ogive)
* Base drag is reduced by base shape (Boat tail)
71
Types of carrier projectiles?
* Smoke
* llumination
* Conventional Anti Personnel
* Sub Projectiles
* Flare
* Incendiary
* Radar Echo
* Chemical
* Propaganda
72
Types of anti-personnel sub-munition in carrier projectiles
* Shrapnel
* Canister Shot
* Flechettes
73
Ingredients of smoke compositions?
* Fuel
* An oxidant
* Dyestuff
* in the approximate ratios of 1 :1 :2.
74
Method of operation for carrier shells
* Bursting - e.g. WP
* Base Ejection - e.g. Illum, Bomblet projectile
* Nose Ejection - e.g.120mm Canister round, 105mm APERS XM546 projectile
* Base Emission - e.g. 105mm SMK
75
Definition of Carrier Projectiles
Carrier projectiles are those in which the projectile body is used as a vehicle for conveying a payload to the target area.
76
Definition of exploder and exploder systems.
Exploder
A charge in the form of a pressed pellet or filled container of secondary explosive designed to amplify the detonation wave produced by a fuze detonator or magazine to ensure efficient detonation of the main charge.
Exploder System
The components used for transmitting the impulse from the fuze or booster to the HE filling.
77
Definition of supplementary charge.
A cylindrical aluminium container, (filled with either TNT or Comp B) which is used to fill the cavity below the fuse in deep cavity projectiles. It is removed when some proximity fuzes are fitted to the projectile
78
Supplementary charges contained in metal provide three main benefits, list them
* Ease of removal
* Setback movement eliminated
* No explosive migration
79
Explain actions on firing for percussion primers.
* Striker/Firing pin strikes the cap
* Crushes the initiating composition against the anvil
* Flash passes through the firing channels in the anvil & plug to the gunpowder in the magazine
* Magazine fires, primer body expands against the cart case, thereby ensuring external obturation
* Ball or Cone is forced back into the fire channels internal obturation
80
# REMEMBER THIS QUESTION
Post firing boost and how they work
* Rocket assisted - Rocket motor inserted at the base of projectile. It is activated after shot ejection.
o Rocket cap is removed before loading
o Burning propellant burns the delay composition – 7 sec
o Delay composition ignites the rocket igniter and main rocket motor propellant
o Boost phase – 2 sec, sustain – 7 sec
o Propellant gases released through venturi
* Base bleed
o Non-ballistic solution achieved by generating gases and filling the vacuum at the base of projectile during flight.
o Solid grain propellant ignited by propellant during firing.
o Burns slowly to fill vacuum which increases air pressure.
o Does not propel round, it eliminates drag.
o Base drag reduce by 70%, increase range by 10% – 20%
81
# REMEMBER THIS QUESTION
Non-metallic materials and different application they use for
* Natural fibres
o Cellulose – polymeric substance found in vegetable matter
Cotton – used for charge bags
Wood/paper – used for cardboard in pyrotechnics
o Silk – used to tie bundles of cordite to form propellant charges
o Wool – used for felt pads
o Rubber – used in Squash Head (inert bitumen pad in the nose)
* Plastics – used in casting of non-metallic land mines and glass fibre rocket motor cases
* Paints and varnishes
o Coating iron and steel surfaces of HE stores.
o Cementing in cardboard closure cups
82
# REMEMBER THIS QUESTION
Breech loading systems and components
* BL guns are loaded with
o Bagged Charge Systems
o Modular Charge Systems (MACS)
* Components are:
o Tubers/ primers
o Bagged charge
o Projectile
83
# REMEMBER THIS QUESTION
How obturation works in breech loaded and quick fire weapon systems?
* BL – rearward obturation is achieved by the gun.
* QF – rearward obturation provided by cartridge case.
84
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Types of cartridge systems and difference in loaded into weapon systems
* Breech Loaded – opens like an oven door
* Quick Firing – breech is closed by simple sliding action
85
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Metal defects. What they are and name them.
* Mechanical – cracking due to stress
* Chemical – corrosion due to impurities
86
# REMEMBER THIS QUESTION
Make up of brass cartridge case
* Copper – 70%
* Zinc – 30 %
87
# REMEMBER THIS QUESTION
Why do we use brass in cartrtidge cases?
* Performs well in most equipment
* Metallurgy and techniques are well known
* Does not corrode to give hard abrasive particles
88
# REMEMBER THIS QUESTION
Combustible Cart cases (CCC)
* Material that is capable of burning and contains ingredients that contribute significantly to the production of the propellant gasses.
* Made from nitrocellulose, Kraft paper and resins. Resembles hard cardboard.
* Looks harmless but is very easily ignited.
* Advantage is that everything loaded into the chamber plays some part in ballistic effect to be achieved.
* Charge bags have a disadvantage that at lower charges of multi-charge system, a disproportionate amount of cloth is loaded. And at low pressures there is a danger of incomplete combustion.
* CCC have been developed for AS90 and Challenger and have achieved a significant reduction in barrel wear.
89
# REMEMBER THIS QUESTION
Tracers – different types and ways of sealing (have a look at the pictures in presentation)
* Types of tracers
o Tracer projectile
o Tracer and Igniter projectile
o Integral Tracer
* Method of sealing
o Brass or Celluloid discs or cups
o Sealing methods vary considerably
o Nitro-Glycerine and Carbamite
o Bakelite discs
* Methods of securing
o Threaded externally to screw into base
o Threaded internally for attachment to a screw-treaded spigot
o Separate screws passing through a tracer body
90
# REMEMBER THIS QUESTION
Driving bands – types, attachments, ways we do things
* Types
o Orthodox
o Modern
o Double
o Gas check
o Probert
* Methods of attachments
o Split ring – a strip of required length is cut, formed into a ring with ends butted together. It is then pressed onto shell by a multi-ram process
o Solid ring – a ring of correct width is cut from seamless copper tube, slipped over the shell and pressed in the same method as for slip ring method.
