General information of artillery
and artillery shells
The artillery piece
as a weapon
(a very simplified description)
The primary sources for this section were
- "Itsenäisen Suomen kenttätykit 1918 - 1995", by Col. Jyri
Paulaharju, ISBN 951-25-0811-7
An artillery piece is a firearm just as a rifle. It operates
on exploding gases created by the propellant charges. The
barrel gives the projectile it's direction. After the projectile
has left the barrel, it flies to the target unguided (today
there are "smart" guidable projectiles developed to be fired
by guns, but that was not the case in World War 2) . The effect
of the projectile in the target is created by the mass of
the projectile or the explosive charge in it.
When a firearm is fired, the propellant charge creates two
forces in the barrel. First, there is the force that gives
the projectile it's energy to fly, and a counter force of
equal size. The counter force is called recoil. The firearms
are generally divided into two groups, guns with recoil (rifles,
pistols, cannons, howitzers etc.) and recoilless guns (bazooka,
panzerschreck etc.) .
In guns with recoil, the end of the barrel is closed, so
the recoil forces it backwards. In small weapons (rifles,
pistols etc.) , the recoil is usually sufficiently countered
by the weight of the weapon and by supporting it (against
the shoulder of the user for example) . In guns (cannons etc.)
the recoil is countered by the weight of the guns and the
recoil system (guns without recoil system roll several meters
backwards when fired) . In recoilless guns, the pressure of
the propellant gases is released backwards eliminating the
effect of recoil.
The barrel of the gun is usually rifled, forcing the projectile
to spin, stabilizing the projectile. Mortars have usually
smooth barrels, so the mortar projectiles have tail fins that
stabilize the projectile in flight.
| The caliber of the gun is determined
by the diameter of the barrel (inside). It's usually represented
in millimeters, mm.
| The length of the barrel is
represented by Calibers (in other words, how many times longer
is the barrel than it's diameter).
A weapon is gun (artillery piece) , if it's BIG. The minimum
caliber of a gun is 20 mm, and it needs two men to operate
it. The guns are divided into different groups by it's intended
use (field guns, coastal guns, antiaircraft guns, antitank
guns, naval guns etc.) .
The range of a gun is affected by its caliber and especially
the length of the barrel. The longer the barrel is, the higher
muzzle velocity is achieved. The size of the barrel is the
largest single reason for the weight of the gun.
The caliber of the gun, and the length of the barrel is
used to divide guns into different classes; cannons, howitzers
and mortars. These classes are further divided into light,
heavy and super heavy (Järeä in Finnish) pieces.
In Finland, the guns are classed as follows;
are guns with below 100 mm caliber and howitzers with below
150 mm caliber
Heavy cannons have
a caliber of 100 mm - 122 mm, and heavy howitzers 150
mm - 200 mm
Super heavy cannons
have a caliber over 150 mm and super heavy howitzers
over 200 mm
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| A cannon is usually a weapon, which
has a barrel length of at least 20 calibers. The cannons have usually
the maximum elevation of 45º, light guns before the 1930s had a
usual maximum elevation of 20º. (Since 1930s, quite many light cannons
had even higher elevation maximums, and today, even heavy pieces
have higher elevation maximums.)
The longer barrels make the cannons heavier than howitzers, but
gives them superior range (as it gives the projectile higher muzzle
velocity) . The lower maximum elevation restricts their use in forested
terrain, since the battery sites must be placed in the open or major
wood cutting has to be done (making it easier to identify battery
sites from the air) .
The cannons fire usually with a flatter
trajectory than howitzers.
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| The howitzers have usually a barrel
length between 12 - 20 calibers, making the howitzers lighter than
cannons of the same caliber Howitzers have usually higher maximum
elevations than cannons, and are more often fired with higher elevations.
This makes howitzers more useful in forested, rough and hilly terrain.
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| Mortars are simple
artillery weapons. It includes a smooth bore barrel resting on a
baseplate which in turn rests on the ground. The mortars have a
barrel length under 12 calibers They fire only indirect fire in
high angles, elevations ranging usually from 40º to 80º. As the
barrel is smooth, the projectiles have tail fins to stabilize the
The mortars are relatively light weapons as they
are intended to operate on lower firing pressures than conventional
artillery pieces (cannons and howitzers) and thus don't need as
strong (heavy) barrels. This makes them extremely useful in rugged
terrain and as infantry support weapons, as light (up to about
70 mm) and medium mortars (usually 81 or 82 mm) are man portable.
The short barrel and lower firing pressure restricts the maximum
ranges of mortars to much shorter than the ranges of other artillery
pieces. It also makes them less accurate, but as the projectile
is inserted by dropping down the barrel from the muzzle, the rate
of fire is high. The simple construction of mortars makes them
also relatively inexpensive compared to heavier cannons or howitzers.
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|The primary sources for the following sections are
- emails from Colonel Jyri Paulaharju to the author.
- "Tykistömuseon 78 tykkiä", by Unto Partanen, ISBN-951-99934-4-4
and general data
All artillery pieces use/fire ammunition that is called a shell
(or round). The shell itself has different parts, which generally
- The cartridge case, which holds
the propellant charge and the projectile.
All artillery shells don't have cartridge cases,
instead the projectile and the propellant charge are loaded "separately",
inserting first the projectile and then the propellant charge.
- The projectile, which is the part
of the shell that is propelled into the target (which contains the
explosive charge / filler)
- The propellant charge, which propels
The separate loading, mentioned earlier, is used
generally with large caliber guns as it gives the chance to reduce
muzzle velocity of the projectile by increasing or decreasing the
amount of the propellant charge, thus affecting the range.
- The fuse, which detonates the explosive
charge (or filler) inside the projectile.
- The primer, which detonates the
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Artillery projectile blast effect
The artillery projectile ( / shell / round) , that lands
in the target, has many different ways to cause damage to the enemy
in the target area.
The different possible damage (or effect) types are generally
pressure, splinter, shock, concussion and psychological. The amount
and type of the blast effect depend mostly on the shape, structure
and the caliber of the projectile. The kinetic energy of the projectile
(to say it simple; the higher the velocity of the projectile is at
the moment of impact, the higher the kinetic energy) , the blast of
the explosive filler (causing a pressure wave) , the splinters that
fan out from the body of the projectile, and even the volume of sound
of the blast, are all common ways in what the blast cause damage in
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(Note that the "side cones" visible
in this picture
are in fact a part of the same cone, spraying a belt
of splinters vertically from the axis of the shell)
In general, when the explosive filler blow up, the detonating
wave converts the explosive filler to gases which in turn exerts extremely
high pressure on the inner surface of the projectile. The projectile
expands until the critical stress for failure is reached. As the projectile
breaks apart, the shear and cleavage sends fragments/splinters flying
with high velocity in (roughly) three separate fans. This is called
fragmentation effect. These fans or cones are the "forward cone",
the "side cone" and the "base spray" (backwards). The aperture of
these cones, and the amount of the splinters in them, depend mostly
on the shape of the projectile (the body of the projectile), and the
shape of the explosive filler inside the projectile. The direction
of the splinters are affected by the velocity and the speed of rotation
at the moment when the projectile explodes.
Usually the majority of the splinters are in the side cone (roughly
80 % of the splinters) , and with the shells fired by cannons and
howitzers, which have cylindrical projectiles, the aperture of the
cone is usually between 40 - 50 degrees. The shells fired by mortars,
are usually drop-shaped, giving the side cone an aperture of over
The forward cone and the base spray usually amount some 20 % of
the fragments released by the shell. The forward cone has usually
more fragments than the base spray.
The reason for this uneven distribution of fragments, is in the
shape of the projectile. The ogive (forward tip of the projectile)
, and the rear end of the projectile don't splinter like the sides
do. The splinters in the side cone are also smaller than the splinters
in the forward cone and in the base spray.
(relatively flat trajectory,
usually fired by cannons and/or
(mortar, and in some cases a howitzer)
These simple drawings show the
basic splinter directions.
Note that a large part of the splinters, fanning out from a
low trajectory shell,
fly up into the air, while the mortar shell, usually coming
from a considerably higher angle, has a better angle of spreading
the splinters around.
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Generally speaking, the blast of the artillery projectile creates
a crater (or a shell hole) , if it penetrates the soil, and explodes
underneath the surface at an optimum depth. The blast throws up soil
high into the air, from which a part scatters around the point of
impact, while a part falls back into the crater and to the edges of
the crater creating a small embankment surrounding the hole. The maximum
depth, where this type of a crater will be formed is roughly 10 times
the caliber, which is usually also the radius of the blast.
Of course, the soil is also a factor. It's obvious that the resulting
crater in soft sand in different than it is in a hard and rocky terrain.
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Fragmentation ranges and
crate sizes caused by different caliber rounds
(The drawings and figures are based on data
supplied by Col. Jyri Paulaharju to the author.)
The crater sizes and fragmentation ranges, shown below, are meant
to be only general examples of crater sizes and fragmentation ranges,
when the ground is common dirt soil. There are large differences between
different shell types and different calibers, in both fragmentation
range and crater size. Note that the fragmentation effect/ranges are
shorter in deep snow. This was especially the case with small caliber
guns (75 & 76 mm) reducing their effectiveness considerably. Also,
as the ground was frozen, the projectiles didn't penetrate the ground
deep enough to blast as large craters as are shown below.
The x- and y-axis have small marks each representing one
meter each. I've also added a dot into it to represent the size of the
Effect of artillery
against "soft" (infantry) targets in a 100 m
x 100 m area
(Chart and data, courtesy of Col. Jyri Paulaharju)
[ This diagram is based on Finnish wartime experience, and is more
of a theoretical graph of artillery effectiveness than a graph which
could be applied automatically to every situation. The graph is based
on the assumption that the point of impact is centered in the target
area, and the area is covered with an optimum pattern. This of course
rarely (if ever) happens in real life. So the purpose of the graph is
perhaps more to illustrate the impact that an accurate barrage(s) has
on infantry. ]
Graph # 1 - the estimated casualties against
unprotected infantry in prone positions (i.e. not in trenches)
Graph # 2 - the estimated casualties against
infantry in entrenched positions, if the defensive works (nests,
earth & soil bunker etc.) are 6 m² in size and a direct hit
or a near miss destroys it, or if the straight sections of the trench
are some 4 m in length.
- An enemy that suffers casualties ranging from 0 - 20 % is considered
to be "harassed"
- An enemy that suffers casualties ranging from 20 - 50 % is
considered to be "suppressed"
(As a further note Finnish experience showed that even 17 % casualties
are enough to efficiently suppress the enemy.)
- An enemy that suffers casualties over 50 % is considered to
be "destroyed" (Meaning that the enemy unit(s) has lost it's ability
to operate efficiently. This can vary depending on training and
I'd like to emphasize that these "casualties" shown
in this graph are suffered in relatively short time (within a few
minutes) , so the graph doesn't mean that a unit that has suffered
25 % casualties e.g. in a week is "suppressed".
Also, this graph doesn't apply to Soviet artillery, as it used a
different firing technique, and had a lower density of grenades
in the target hectare.
Back to Artillery weapons in
the Winter War
Artillery pieces of both sides