tiated. This shock is normally provided by a high
(b) Cap, blasting: nonelectric, M7. The stan-
strength blasting cap; the Nonelectric M7 or the Electric
dard Army nonelectric blasting cap is the M7. The open
M6. The MDI family consists of high strength blasting
end of M7's cup is flared to make insertion of fuse or
caps, low strength blasting caps (low-strength caps are
coupling base nipple easier. Nonelectric blasting cap M7
being phased out) and boosters. Shock tube priming of
replaced the older J-1 cap. Nonelectric blasting caps M7
explosives offers the instantaneous action of electric ini-
are packed 6 caps per carton, 1 carton per waterproof
tiation without the risk of accidental initiation of the
bag, 50 bags per fiberboard container, 12 containers
(3,600 caps) per wooden box.
area, or by static electricity discharge. The MDI is ex-
tremely reliable. Each shock tube blasting cap assembly
and booster assembly is a factory-crimped and sealed
sists of a core of PETN in a textile tube coated with a thin
unit that is impervious to moisture (unlike standard non-
layer of asphalt. On top of this is an outer textile cover
electric blasting caps).
finished with a wax gum or plastic coating. One hundred
feet of detonating cord is wound per spool and 50 spools
(5,000 ft) are packed in a wooden box. Five hundred feet
of detonating cord is wound per spool, 1 spool is sealed
The terms "shock tube" and "minitube" are
per can, 8 cans (4,000 ft) per wooden box. The weight of
interchangeable. Both perform the same
the box with contents is 117 pounds. One thousand feet
functions. The differences are with tube
of detonating cord wound on a spool is packed in a card-
wall thickness and diameter. Manual will
board box and sealed in a barrier bag. Detonating cord is
use "shock tube" for narrative.
used to prime and detonate other explosive charges. Det-
onating cord used alone functions as an explosive charge.
The shock tube is a thin walled plastic tube with a layer
b.1. Modernized Demolition Initiators (MDI). MDI
of explosive material deposited on its interior surface.
is the project name given to a new family of nonelectric
Functioning of the shock tube is usually evidenced by a
blasting caps and associated items being introduced to
flash within the tube. The free end of the shock tube
replace the M7 Nonelectric Blasting Cap, M700 Time
blasting cap is always sealed. For field expediency, all
Fuze and electrical initiating systems, and partially re-
shock tube-type blasting caps may be extended by the
places detonating cord. The snap-together MDI compo-
user using left-over pieces of shock tube from previous
nents will allow simplification of some types of
operations and the short pieces of splicing tubing sup-
explosive priming and improve reliability, ease and safe-
plied with the M12 and M13 Caps.
ty of all explosive priming systems where they are used.
Military explosives require a substantial shock to be ini-