Internal ballistics is the study of what happens inside the barrel of a firearm from the moment of ignition until the projectile exits. When fired, the projectile is accelerated to high velocity by the burning of propellant gases trapped behind it in the barrel. There are three types of propellant powders - progressive powders increase burning surface as they burn, degressive powders decrease burning surface, and neutral powders maintain a constant burning surface.

1. BURNING OF PROPELLANT
(INTERNAL BALLISTICS)

2. Internal ballistics is the study of what
happens within the barrel of a weapon from
the moment the firing pin hits the primer to
the time the bullets exits from the barrel. It is
mainly concerned with propellant pressures,
acceleration of the missile whilst it is in the
bore, muzzle velocity and recoil.

3. When a projectile weapon is launched from the
gun barrel, it is accelerated to a high velocity by
the burning of propellant.The propellant may
travel with the projectile or be stationary in the
barrel.The gasses produced by the burning
propellant are trapped in the volume behind the
projectile.The introduction of more heat into
the product gasses causes the pressure to rise
which in turn will accelerate the projectile. On
the other hand, the movement of the projectile
increases the volume which tends to drop the
pressure.

5. There are three different types of powder
which helps in propellant burning which are
as follows
PROGRESSIVE POWDER
 as burning proceeds, the total burning
surface increases.
 Multi-perforated and rosette grains burn
progressively

6. Fig :showing multiple
perforated grain
fig.showing
Progressive powder
curve

7. DEGRESSIVE POWDER
as As burning proceeds, the total burning surface decreasestotal
 Propellants formed in pellets, balls, sheets, strips, or cord burn
degressively.
Fig showing curve for degressive powder

8. CONSTANT BURNING POWDER OR
NEUTRAL BURNING
 as burning proceeds the total burning surface
remains approximately constant
 Single perforated grains and star perforations
result in neutral burning
 Fig. showing single perforated grain

9. Fig. showing curve for neutral or constant
burning

10. COMBUSTION:-
 Oxidation reduction process.
 It takes place when the reaction of the
burning propellant/substance arise out of its
contact with the air in an open space.
 Oxidation- o2 molecule is added
Reduction-02 molecule is reduced

11. DEFLAGRATION:- it includes violent and rapid
burning and is intermediary step between
gradual combustion and detonation
 Slow rate of burning
 E.g. in low explosives such as propellant
DETONATION:-
 It takes place when the explosion is extremely
rapid and the formation of gases is almost
instantaneous
 E.g. in high explosives