Misfires

TM 9-1375-213-12-1

WARNING

c. Do not attempt to repair any kit components

Never set up or attempt to fire the M180

beyond that provide in Chapter 3.

( o r any other electrically-initiated

d i r e c t l y - o p e r a t e d demolition circuit)

WARNING

during periods of impending or active

Connection of blasting machine to field

firing lead is the last operation prior to

e l e c t r i c a l storms.

firing. To avoid premature connection

1-11. Misfires

and firing, operator in charge will have

Except as otherwise indicated in paragraph 1-10

the blasting machine with him at all

above, this ammunition is safe to handle and fire.

times.

However, the following potentially hazardous

conditions, which could arise during firing, should

d. If there is overhead cover at the firing loca-

be handled as indicated to avoid injury to person-

tion, the firing location may be as close as 500 feet

nel and damage to equipment:

(150 meters) from the nearest kit. If there is no

a. Misfires and Hangfires. A misfire is a com-

overhead cover, the firing location cannot be

plete failure to function. A hangfire is a failure

closer than 4000 feet (1200 meters) from the near-

to function involving an abnormal lag beyond the

est kit. The restriction also applies to all personnel

instant of initiation. Because electric initiation is

in the area. The minimum distance, in any case,

used with this kit, hangfires of more than a second

are unlikely

is 500 feet (150 meters) from the nearest kit.

b. Causes of Misfires.

WARNING

(1) Improper electric or nonelectric connec-

tions.

The yellow tagged safety plug is a short-

(2) Damaged electric or nonelectric firing cir-

ing device for the kit's electro-explosive

cuits.

initiators and must be in place when

(3) Improper operation of blasting machine.

working in the area of an assembled kit

(4) Deteriorated M6 electric or M7 nonelectric

or when a rocket motor is being handled.

blasting cap that is non-functional or too weak to

The safety plug must be removed prior to

initiate detonating cord or explosive.

firing.

(5) Defective 500 millisecond delay blasting

cap or M2 squibs that will not fire at all.

NOTE

(6) Deteriorated propellant grain, detonating

If the safety plug is lost or missing,

cord or explosive charge.

a safety plug (the original or one

(7) Malfunctioning blasting machine.

from previously fired kit) should be

c. In the event of a misfire:

installed as soon as possible. Do not

(1) Assure that firing wires are securely con-

handle a kit without a safety plug any

nected to blasting machine terminals.

more than necessary. Do not transport

(2) Actuate blasting machine again several

a kit without a safety plug any long

times with maximum possible effort,

distance.

(8) If repeated actuation of blasting machine

does not fire kit(s), remove firing lead from blast-

WARNING

ing machine and recheck firing circuit with blast-

As with all ammunition containing elec-

ing galvanometers or Blasting Cap Test Set M51

tro-explosive initiators (EEI), avoid

to determine the most probable cause of trouble

transporting or operating the M180 Dem-

(i.e., an open or a shorted circuit).

olition Kit in the vicinity of operating tel-

NOTE

evision, radio, radar, etc, transmitters.

Lighting of indicator lamp on Tent Set

The radio frequency (RF) energy emitted

M51 indicates that the circuit is contin-

by these transmitters can fire the EEI

uous; the test set cannot indicate whether

under some circumstances even with the

such a circuit is a GOOD firing circuit or

shorting devices in place, for example, do

a SHORTED circuit. In addition, a re-

not operate or transport the kit within

sistance reading on a blasting galvanom-

eters does not necessarily rule out the pos-

100 feet (30 meters) of an operating walk-

sibility of a short, since resistance will be

ie-talkie. Figures for safe distances from

present if the short is located some dis-

various powered transmitters are given

tance from the blasting machine,

in TM 9-1300-206, Appendix C.

(4) After determining the most probable cause

Change 2

1-16