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