AT SGT Cartridges and Projectiles Flashcards
What 4 natural fibers are used in the manufacture ammunition components?
Cellulose
Silk
Wool
Rubber
Where is cellulose used in ammunition components?
Cotton charge bags
Cardboard in pyrotechnics
Polymetric substances from vegetable matter
Where is silk used in ammunition components?
Tie cordite bundles
Propellant charge bags
(Stable, Expensive, no residue)
Where is wool used in ammunition components?
Old gunpowder igniter
Felt pads
(high water absorbtion rate)
Where is rubber/synthetic rubber used in ammunition components?
Rubber/bitumen composite in HESH rounds
What are the 2 types of plastics in ammunition components?
Thermoplastic - Reshaped when heated (limited times) (cordite same property)
Thermosetting plastic - Can not be softened by heat (plastic mines, rocket cases)
What are 5 paints and varnishes used in manufacture of components?
Copal varnish (ammonium nitrate protection)
Shellac (protect brass from cordite N2O)
Varnish based on bitumen
Coatings for iron and steel
Cementing cardboard, closure caps
What is a used to create a soft setting non-permanent seal?
Luting
What are 4 common alloys used in EO?
Steel - Iron with carbon
Brass - Copper and Zinc
Aluminum alloyed with Copper, magnesium, Mg+silicon, Mg+Zinc
Mazak - Mg, Al, Zn, Cu
Name the 2 defect types that effect metals in EO?
Mechanical - cracks due to stresses
Chemical - Corrosion due to impurities
When are stresses likely to be formed and what can aggravate them?
Mostly likely during manufacture then aggravated by environmental conditions
What is corrosion?
Conversion of a metal to a non-metallic state through a chemical reaction
What is seasonal cracking?
Extreme heat, cold and humidity corrosion stressing brass, ammonia amplifies this effect by creating cupramonium from the copper which is very hygroscopic.
What are 5 types of corrosion?
Rust (Ferrous oxide)
Aluminium oxide (tail fins)
Cupriz Azide contamination (Lead azide+moisture->acid->copper azide very sensitive)
Zinc exudation “free copper” (copper disolves out of brass - pores created)
MAZAK contamination (Alloy breakdown from impurities - leech to surface - cracking)
What are the requirements for cleaning SAA?
Abrasive 0, nylon pad, 1 on 1 off to avoid heat spots
Wipe clean - steel repainted
Unservicable if pitted/flaking
4 techniques of filling HE?
Casting
Pressing
Extruding
Preforming/cocooning
What are 5 considerations of casting and extruding HE fill?
Cooling range
Shrinkage
Structure
Cooling rate
Dust migration
3 types of casting HE fill?
Straight pour
Creamed
Liquid and biscuit
3 drawbacks of hot/melt filling HE?
Shrinkage - Encapsulation filling by polyurethane under vacuum
- Pre cast encapsulation
Dusting - Terylene, glass fibre, Add lubricant
Cracking - Additives, seeding
5 shell linings go into HE shells?
Shellac
Copal varnish
Bitumen/castor oil
lacquer
Resin/TNT paint
What are the reason dark ignition is required?
Do not dazzle the firer
Do not give the firers position away to the enemy
4 requirements of tracer?
Luminosity
Strength - survive firing forces, constant rate of burn
Consistency of performance - always ignite, no early burn out, SD
Ease of ignition - density makes hard to ignite
2 means of ignition for tracers?
Direct ignition - setback initiate
Propellant ignition
3 classifications of tracers?
Tracer projectile
Tracer & igniter projectile
Integral tracer
Describe the tracer projectile type of tracer classification?
Hollow steel rod threaded into munition
Tracer then priming composition pressed into sealed recess
Describe the tracer & igniter type of tracer classification?
Steel or brass hollow rod threaded into the munition
An igniter composition will function from the end of the tracer composition usually functioning a self destruct
Describe the integral tracer type of tracer classification?
Solid shot with a recess has tracer then primer composition press into it then sealed.
What are the 2 types of primers?
Percussion
Electric
What are the components of the percussion primer?
Body - Contain all, magazine attaches
Cap - Flush to body
Anvil - pinch composition
Plug - obturation
Magazine - gunpowder
What are the 2 types and the components of the electric primers?
Bridge wire
Base - hold ebonite core
Contact piece - contact cap
Bridge - irido platinum wire in contact with composition
Magazine - gunpowder
Conducting cap
Base - plastic cap
Pole unit - brass pole, spring to maintain contact
Cap - brass pole surrounded by graphite infused composition
Magazine - Gunpowder
3 functions of a driving band?
Center the projectile in the bore and impart spin
Prevent forward escape of gases
Assist preventing slip back
What are the 6 requirements of the driving band?
no excessive pressure on barrel or shell
Cater for bore diameter wear
Firmly attach to the projectile
Not alter the ballistic properties
No excessive friction on the bore
Simple to make and fit
What are the 2 methods of attachment of a driving band to the shell?
Split ring
Solid ring
what 2 methods are used to stop the driving band twisting on the shell?
Wavy rib
Knurling
What is the purpose of slipping rings / slipping driving bands?
Minimise the spin imparted by the barrel being imparted on the projectile
Name 6 types of driving bands?
Orthodox
Modern band
Double band
Gas check type
Probert
Slipping rings
What is a metal?
Class of elementary substance that is crystalline when solid characterised by opacity, ductility, conductivity and lustre when fractured.
Define malleability?
Ability to be shaped without breaking it’s structure
Define ductility?
Ability to be drawn out without effecting the structure.
What does it mean to anodise metal?
Apply an electrolytic passivation process to add more oxidisation layers to a surface.
What are 4 properties of iron?
Heavy
Ductile
Malleable
Occurs naturally
What are 3 properties of copper?
Ductile
Malleable
Conducts electricity and heat
What brass is used for cartridge cases?
Cartridge brass
70% copper
30% Zinc
What are the 3 reasons to use brass in cartridge cases?
Performs well in more equipment
Metallurgy and techniques are well known
Does not corrode giving hard abrasive particles
What is the mix of brass for gilding metal?
95% copper
5% Zinc
What is the mix for Admiralty brass?
69% copper
30% zinc
1% tin
Fill in the blanks
What is a projectile?
Object capable of being propelled by force, usually a gun, travelling by it’s own kinetic energy
What is the ogive on a projectile?
the ballistic shaped section ahead forward of the shoulder
What is the bourrelet?
The front band. A band is a section of the shell wall accurately machined to a greater diameter than the rest of the body.
What is a projectile fuze?
The payload initiator that holds the firing, safety and arming mechanisms.
What are 3 types of projectiles?
Operational
Weapon functioning/inspection
Training
What are the 3 components of a breech loading cartridge system?
Tubes/primers
Bagged charge
Projectile
What are the 3 types of quick firing systems?
Quick firing separate
Quick firing semi-fixed
Quick firing fixed
How is obturation achieved on a quick fire gun?
Rear cartridge case
Forward projectile
What are the 4 requirements of a cartridge case?
Protect the contents
Provide efficient obturation
Easy loading and extraction
Able to house a primer
What are 8 properties of charge bags?
Protect and contain the content
Leave no smoldering particles or residue (design consideration)
Totally consumed on firing
Allow flash from ignition to pass easily through
Non-smoulder
Non-stretch
Non-wear
Be insect, vermin, rot proof
What are 2 design principles for charge bags?
Lowest charge must be stable (hold shape, no misfire or delay in ignition)
Igniter always on lowest charge
What are 5 design characteristics of charge bags?
Normally cylindrical in shape
Charge comprises igniter and propellant
Propellant in stick form is held by silk of silk braid
Granulated propellant is filled loose
Lifting beckets on large bags
What is a quick fire fixed cartridge system?
Projectile and cartridge are joined
Loaded together
Rammed together
Charge not adjustable
What is a quick fire semi fixed system?
Projectile and cartridge are packed together
Loaded together after mating
Rammed by cart
Charge is adjustable
What is a quick fire separate system?
Projectile and cartridge are separate
Loaded as 2 units
Projectile rammed before cartridge loaded
Charge is adjustable
What are the 2 designs of recoilless ammunition?
Solid cartridge case with blow out disc
Perforated cart case
How does a recoilless blow out disc system work?
The cartridge case is loaded with the primer lined up with the firing pin. The weapon is fired and the propellant charge functions. The pressure builds rupturing the disc and propelling the projectile. Propellant gases exit the open rear breech out through the venturi.
How does a perforated cart case system work?
The cartridge is locked in a closed breech. On firing the propellant charge burns through the case lining and out the cartridge holes into the annular space and around the breech through the venturi out the rear. The pressure propels the pre-rifled projectile forward.
What are 3 disadvantages of recoilless weapons?
Flash and dust signature (BBDA)
Low velocity
Large propelling charge
What are 4 types of bagged charges?
Equal
Unequal
Stem and ring
Stem and segment
What is de-coppering?
Tin or lead foil melts to copper left from the driving band. The now brittle metal is cleared by the next projectile
What are the 7 charge types?
Normal
Super
Reduced
Fractional
Incremental
Blank charges
De-coppering charge
What are the 2 types of combustible cartridge types?
Combustible - When is burns is contributes significantly to the production of gases
Consumable - When burns does not contribute to the explosive process
How do rocket assist projectiles work for projectiles?
The cap is removed from the base of the projectile and when fired the propellant ignites a delay in the rocket motor. After it has exited the barrel the delay functions the solid rocket motor and the gases exit the venturi propelling the projectile faster.
How does base bleed work for projectiles?
The burning propellant ignites a pyrotechnic composition in the rear of the projectile which burns slowly releasing gas filling the vacuum behind the base of the travelling projectile reducing the drag.
What 5 tasks must a cartridge case fullfil?
Protect the propellant in storage
Provide early obturation with quick expansion
Recover to a diameter less than the chamber
Withstand extraction forces intact and withdraw without jamming
Support a fixed round projectile at the mouth of the cartridge
What are 6 factors that affect shell design?
Target effect
Ballistic performance
Strength to withstand firing stresses
Economy in manufacture
User requirements
Safe handling, transport and storage
What are 8 forces acting on a projectile?
Gas pressure - rear
Acceleration
Setback
Heat
Centrifugal
Driving band pressures
Side slap
Drag
How can the shape of the projectile reduce drag?
Nose drag - Ogive
Base drag - boat tail
What are 3 methods used to manufacture HE shells?
Cast
Forged
Extruded
Define a carrier projectile?
The projectile body is used to transport a payload to the target area.
List 9 types of carrier projectile?
Shrapnel
Cannister shot
Flechettes
Sub projectiles/munitions
Incendiary
Chemical
Flare
Radar echo
Propaganda
What are 3 benefits of a supplementary exploder charge in a metal casing?
Ease of removal
Setback movement eliminated
No explosive migration
