PS Magazine - TB 43-PS-564
PS, The Preventative Maintenance Monthly
ISSUE 564
NOVEMBER 1999
Dear Editor,
We recently finished an inspection of our post’s M120/M121 mortar gun
tubes. Humidity and temperature changes had left condensation in the
bottom of several tubes that had caused extensive corrosion. The tubes
had to be replaced at a cost of $22,000 each.
These tubes could have been saved if mortar crews had just paid a little
attention to PM. Pages 2-50 to 2-51 in TM 9-1015-250-10 say to clean
and lube the tube throughly after firing and to clean and lube it again for
the next two days. When the mortar just sits, clean and lube the tube
weekly.
It’s also a good idea to store the tube in the arms room, NOT in the
M1064 carrier. Condensation is less of a problem in the arms room.
Just doing a little bit of PM weekly can save units thousands of dollars.
CW2 Angel Roman
B Co, 203d FSB
Ft Benning, GA
M2 Machine Gun . . .
PS 564
39
NOV 99
PS 564
38
NOV 99
M120/M121 Mortars . . .
uh-oh,
that's gonna
cost my unit
a
bunch
of
money
.
it looks
like you've got a
lot of
corrosion
down there.
Thanks, Chief. We hope mortarmen
take your advice. Units don’t need to
be spending big bucks on replacing
tubes that could easily be protected
with PM.
here’s a lot at stake in how you stake parts of the M2 machine gun. If you
stake the wrong part, you hurt the M2 so badly that it has to go all the way to
depot for repair. Here are the rights and wrongs of staking:
Right
The barrel locking spring
needs staking. If the
spring works loose,
the machine gun can’t
hold headspace and it
starts rupturing car-
tridges. That’s dangerous.
So, if the spring’s loose, swage
the barrel extension once firmly with a
1
/
4
-in
flat-tip punch. Swaging is just staking with a flat-
tip punch. If the barrel extension is damaged in the swaging area, swage the
opposite side of the barrel extension. As long as you don’t crack the spring or
punch a hole in the spring and the spring lets you install the barrel, the spring
is usable. Use a stone on any burrs.
Wrong
Never stake the front sight cover
or the breech lock depressors.
The front sight
cover is
held on
by pins
that run
through the receiver.
Staking the cover makes it
impossible for the pins to do their job.
So get support to replace a loose sight
cover. They can do it for around 50 cents.
The breech lock depressors are sup-
posed to be loose so they can move up
slightly when they hit the cam in the barrel extension.
If locking
spring’s
loose,
swage
it with
a
1
/
4
-in
flap-tip
punch
...or breech lock depressors
Don’t stake front sight cover.
..
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