DETONATORS ; PROJECTILES.
327
the high temperature developed on impact being sufficient
to fire the explosive charge. For calibres below 65 milli-
métré (2.559 in.), the projectiles are fitted with a percussion
fuse at the base ; these are fired niainly against small craft,
carrying but little protective armour, or quite unprotected.
facture, and the surfaces treated chemically. A circular
blank is used, the diameter and thickness of which
dépend upoii the dimensions of the finished case. Fig. 1050
shows the process of manufacture followed for a 15-
centimetre (5.905 in.) cartridge case.
Standard Types of Shell.
FOg 1051 rig. 1052..
Steel Armour-Piercing Shell.
Fùj. 1050.
The Making of
Flat and Concave Base of Cartridge
Case.
a Cartridge Case.
They penetrate easily the sides, and their vis-viva may not
be sufficient to fire the explosive charge ; they are there-
fore provided with a percussion fuse.
CARTRIDGE CASES.
The Schneider-Canet cartridge cases are characterised
by the method followed in their manufacture, by the
special quality of the metal used, and by their design.
They are obtained by successive chasing and drawing
operations, the cases being annealed in course of manu-
The Schneider-Canet cartridge cases are divided, as
regards shape and without distinction of calibre, into two
main classes :
Flat-bottomed cases, for medium calibre guns.
Concave-bottomed cases, styled safety cases, for small
calibre guns.
The first include the cases for guns with screwed
breech-blocks; the second, those for guns with concentric
threaded breech-blocks. Each dass contains complété cases,
distinguished from each other according to the way in