LO4 - Cartridges and Projectiles Flashcards
What are different way to compensate spin in shape charge rounds?
- Slipping driving bands
Carl Gustav 84 mm HEAT round - Fluted liners
Attack Helicopter 30 mm HEDP round - Spin compensated liners
What are the factors affecting performance of HESH rounds?
- 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
What are the different types of natural fibres?
- Cellulose
- Silk
- Wool
- Rubber
What are the 2 differnt types of plastic and the main difference between them?
- Thermoplastic - Thermo Plastic can be reheated and reshaped
- Thermosetting plastic - is incapable of again being softened by heat
What is used for non-permanent seals?
Luting
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What are the different types of defects?
- Mechanical
Cracking due to stress - Chemical
Corrosion due to impurities
What is Annealing?
- Relief of work stresses i.e. annealing makes larger crystals at neck softer
- Often performed on cartridge neck after forming
Define corrosion.
The conversion of metal to a non-metallic state
Types of corrosion.
- 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
What is the charge to weight ratio (CWR) in modern HE?
20 to 30%
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What are the different filling techniques?
- 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
What are the disadvantages when casting using hot melt process?
- Shrinkage
- Cracking
- Dusting
What are the principle requirements of tracer
composition?
- Luminosity
- Strength
- Consistency of Performance
- Ease of Ignition
What are the classification of tracers?
- Tracer Projectile
- Tracer and Igniter Projectile
- Integral Tracer
What are the means of igniting tracer?
- Direct ignition
- Propellant ignition
What are the types of primers?
- Percussion
- Electric
Bridge wire,
Conducting cap
What are the design features of a primer?
- 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
Components of a primer and explanation?
- 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
Types of obturating systems
- Cap Holder
- Ball in Cone Seating
- Cone in Cone Seating
- Firing Plug and Bty Cap
Components of bridge wire electric primer?
BBCM
- 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
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Components of conducting cap electric primer?
BPCM
- 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
Definitions of round, projectile and component.
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
Types of projectile
- Shot
- Shell
- Carrier
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Different parts of projectile
- Body
- Head
- Shoulder
- Driving band
- Ogive
- Band (Bourrelet)
- Band
- Base
- Wall
- Cavity
- Lip
- Fuze hole
- Governing section
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
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.
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)
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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
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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
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
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
Methods to prevent twist of driving band from projectile
- Wavy rib
- Knurling
What are the types of driving bands?
- Orthodox
- Modern band
- Double band
- Gas check type
- Probert
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
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
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Advantages of breech loading system?
- Less stowage problems / reduced length
- No Cart Case