PS Magazine - TB 43-PS-569
PS, The Preventative Maintenance Monthly
ISSUE 569
APRIL 2000
APR 00
Put yellow
dots on
breech
locks that
pass
hardness
test
number of breech locks have turned
up that are too soft to use with the M2
machine gun. Soft breech locks cause
bad headspacing, which leads to rup-
tured rounds, damaged M2s, and in-
jury to gunners.
So, armorers, before your M2s go
to the field again, check their breech
locks.
Any
breech locks that are
cracked, chipped, burred, or heavily
worn should be replaced.
Breech locks stamped with part
number 7161302 and those with no
stamped part number should be tested
by your support for hardness before
they are used.
M2 Machine Gun . . .
deficiency report (QDR) to TACOM-
RI, ATTN:
AMSTA-AR-QAW, Rock
Island, IL 61299. Fax it to DSN 793-
6653, (309) 782-6653. E-mail it to:
QAWQDRS@ria.army.mil.
Order replacement breech locks with
NSN 1005-00-716-1302.
See TACOM-RI Safety-of-Use-
Message (SOUM) 99-03 for more info.
Your TACOM-RI LAR has a copy.
To be usable, a breech lock should
test in the C50 to C60 range. To get
the hardness tester, contact your local
TACOM-Rock Island (TACOM-RI)
logistics assistance representative
(LAR) for help or contact the manu-
facturer directly. Call Pacific Trans-
ducer Corp at (310) 478-1134 and ask
for hardness tester model 316 (scale
C20-C65). It costs $525.
If the breech lock passes the hard-
ness test, mark it on the right and left
sides with dots of yellow paint so that
you know it’s good.
Breech locks that don’t pass should
be turned in with an SF 368 quality
E
verything isn’t “just the same” when
you mount the M203 grenade launcher on
the M4/M4A1 carbine instead of the
M16A2 rifle, armorers.
For one thing, an accidental nudge to
the M203’s quick-release button can let
the M203 come loose. A retaining spring,
NSN 5340-01-452-9637, keeps that from
happening. Fit the spring on the bracket
behind the button to prevent the button
from being depressed.
When the M203 is mounted on the M4/
M4A1, the sling swivel can’t be mounted
on the left side of the barrel because it
interferes with the M203 barrel release
latch. Solution: Mount the sling swivel on
the right side. See Para 2-16 in TM 9-
1005-319-23&P for the procedure.
When the M203 is mounted on the M16
rifle, the handguard holds the pin for the
barrel stop in place. But the M4/M4A1
handguard doesn’t reach that far, so the
pin can work out. No problem. Stake the
hole edge once only on both sides of the
receiver with a center punch.
M4 Meets the M203
43
i don't know.
i just feel a little
soft
around my
breech lock
.
hmmm,
that could be
serious
.
Mount
swivel on
right side
Stake pin hole edge once
only on both sides of receiver
Clip keeps barrel from coming loose
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