PS Magazine - TB 43-PS-685
PS, The Preventative Maintenance Monthly
ISSUE 685
DECEMBER 2009
22
PS 685
DEC 09
New Firing Pin
M224 operators and armorers also need to be aware that the old three-piece fring
pin confguration (fring pin, fring pin guide, and threaded plug) has been replaced
by a two-piece confguration (fring pin and threaded plug).
All M224s can use the new two-piece confguration, but only old mortar cannon
tubes with an alignment pin in the fring pin well can use the old three-piece
confguration. IF you use the old confguration in a mortar missing the alignment
pin, the mortar could accidentally fre.
Any
cannon
manuFactured
aFter 2005 and/or having a serial
number higher than 3387 should
use the two-piece confguration.
It’s OK to continue to use the
three-piece confguration in older
cannons as long as they have a
serviceable alignment pin in the
fring well. IF the alignment pin is
missing or in poor condition, get
the new fring pin confguration.
Even iF the cannon has a good
alignment
pin,
you
should
replace the old confguration with
the new one the next time the
mortar is serviced.
Purge bench stock oF the old fring
pin confguration and replace it with
the new fring pin, NSN 1015-01-
546-6617, and threaded plug, NSN
5935-01-546-6679. They must be
ordered together the frst time. The
new fring pin can’t be used with the
old plug and the old fring pin won’t
work with the new plug.
Make sure the fring selector on
the handle and fring mechanism
can be rotated through the T
(trigger fre), S (sa±e), and D (drop
fre) positions. I± it can’t, the M224
needs to be sent to direct support
±or evaluation.
Also make sure the selector aligns
correctly with the three positions. I±
it’s in between positions, the mortar
could accidentally fre on sa±e. I± you
have any doubts, the M224 needs to
be sent to direct support.
Steps to
Safe Firing
M224 Mortar…
Steps to
Safe Firing
one m224
mortar unit had
a mortar fire
when it wasn’t
supposed to.
to prevent that
happening again, all
m224 operators
should always do
this check before they
prepare to fire…
for more
information,
see
tacom
safety of
use message
09-026
.
Make sure selector can be
rotated through three positions
and selector is aligned correctly
Two-piece confguration replaced old three-piece fring pin confguration
Older cannon tubes can use three-piece
confguration iF alignment pin is installed
in fring pin well and is in good shape
Pin
685.22-23.indd
1-2
10/16/09
5:41:02 PM
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