PS Magazine - TB 43-PS-689
PS, The Preventative Maintenance Monthly
ISSUE 689
APRIL 2010
22
PS 689
APR 10
23
PS 689
APR 10
F
or the M240-series machine guns, there are two distinctly different operating
rods and sears. These op rods and sears aren’t interchangeable between the
M240 models. If the wrong op rod and sear are used, you could end up with a runaway
gun, plus damage to the M240.
So right now, check all your M240s for the correct op rod and sear.
I
f the Fring pin on any of the
Army’s mortars is too short or
too long, the mortar won’t Fre
because the Fring pin can’t ignite
the cartridge’s primer correctly.
That
means
the
mortar
crew
has
to
go
through
the
whole
misFre procedure, which would
be a serious problem in the heat
of battle.
That’s why it’s very important
mortar crews regularly check the
protrusion of the Fring pin as part
of their BE±ORE PMCS. The
81mm and 120mm mortars have
gages that show the minimum/
maximum acceptable length of the
Fring pin. Measure protrusion with
the gage. If your Fring pin doesn’t
measure up, use the spare Fring pin
that’s part of the mortar’s BII. And
tell your armorer so he can order a
new Fring pin.
Users
of
the
60mm
mortar
will need to have the Fring pin
protrusion checked by support.
The M240B, M240D, M240G, M240H,
M240L, and M240N should have the
double-notched op rod, NSN 1005-01-413-6992,
and double-notched sear, NSN 1005-01-409-0144.
If your
M240 has the
wrong op rod
and sear, tell
your armorer.
Don’t fire it.
The M240, M240C and M240E1
should have the single-notched op rod,
NSN 1005-01-033-3901, and single-notched sear,
NSN 1005-01-033-1524.
The double-
notched sear has
an extra step on
the top.
M240-Series Machine Gun…
Mortars…
Firing Pins Don’t Work?
for more information, see tacom lcmc gpa message 10-002:
Got the
Right
Op
Rod?
Measure Fring pin with
gage during BE±ORE PMCS
hey, why
didn’t
you fire?
my
firing
pin is
too
short.
now we have
to spend
time doing
the misfire
procedure!
Single notch
operating rod
assembly
Double notch
operating rod
assembly
689.22-23.indd
1-2
3/5/10
3:04:02 PM
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