PS Magazine - TB 43-PS-572
PS, The Preventative Maintenance Monthly
ISSUE 572
JULY 2000
ow loose is too loose when it comes
to the coarse deflection (azimuth) scale
of the M64A1 and M67 sights for
the M224, M252, and M120/M121
mortars?
The before-operation checks for all
these mortars say to check that the
coarse deflection scale pops up into
the secured position when you release
it and stays at that locked setting and
doesn’t move freely. If the scale doesn’t
pop up or if it moves in the secured
setting, the sight’s not mission capable.
M224, M252, M120/M121 Mortars . . .
the plungers stick in their holes. Then
the scale won’t pop into or stay in the
secured position.
Often, just letting the sight dry out
completely will fix that, but drying can
take a couple of days. Support some-
times has to replace the plungers.
Use the sight’s cover as much as pos-
sible in the rain. Better yet, keep the
sight in its carrying case when you’re
not shooting.
Some mortarmen have been con-
cerned that they can move the scale
when it’s in the secured position. But
they shouldn’t be. As long as there’s
slight resistance (3 lb-in) when you try
to move the secured scale, it’s good to
go. Only if there’s no resistance or if
the scale moves during firing does the
sight need to be turned in for repair.
But if you have doubts about the scale,
have support check it out.
One thing you can do to keep the
scale popping up is to keep the sight
dry. The scale plungers have a cloth
base. The cloth is water-resistant, but
not waterproof. If the sight gets soaked
in a heavy rain, the cloth swells and
Does scale pop up when you release it?
If scale moves without resistance, turn it in
tell me,
doc, am i
losing
my
sight
?
no
, your
deflection scale
is still
tight
.
Keep sight covered in rain
PS 572
39
JUL 00
PS 572
38
JUL 00
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