PS Magazine - TB 43-PS-575
PS, The Preventative Maintenance Monthly
ISSUE 575
OCTOBER 2000
3.
Press the trigger. If the gun doesn’t
fire, go to the next step. If it does fire,
you’ve got early timing.
If the GO end fits and the NO GO
end doesn’t, the headspace is OK. If
the GO end still won’t fit, repeat these
last five steps until it does.
Do not unscrew the barrel more than
five clicks beyond the first two clicks
in steps 1–5. If you have to turn the
barrel more than seven clicks,
something’s wrong. Tell your armorer.
Headspace Too Loose
If the NO GO end of the gauge fits
into the T-slot, the headspace is too
3.
Ease the bolt forward.
4.
Pull back on the charging handle
until the barrel extension and trunnion
block are about
1
/
16
inch apart.
.
2.
Unscrew the barrel one click.
Headspace Too Tight
If the GO end won’t fit, headspace
is too tight. Do this:
1.
Pull back the charging handle until
the barrel-locking spring lug is cen-
tered in the
3
/
8
-in hole.
the extractor and try to insert the GO/
NO GO gauge all the way up to the
ring into the T-slot between the bolt
face and rear of the barrel.
If the GO end goes down the T-slot
to the center ring and the NO GO won’t
go in, headspace is OK.
6.
Ease the bolt forward.
7.
Pull the charging handle back until
the barrel extension and trunnion block
are no more than
1
/
16
inch apart.
Go
No go
Repeat the five steps until the GO
end fits, but the NO GO end doesn’t.
How to Time
After headspacing comes timing.
1.
Pull the charging handle all the way
back and cock the weapon. Ease the
bolt forward.
2.
Pull the bolt back far enough to in-
sert the NO FIRE gauge between the
barrel extension and trunnion block.
Insert the beveled edge of the timing
gauge against the barrel notches.
Slowly release the charging handle.
PS 575
47
PS 575
46
OCT 00
loose. To fix loose headspace, do the
same five steps you did for too tight
headspace, except screw
in
the barrel
one click.
4.
Unscrew the barrel two clicks,
remove the link and let the bolt go
forward.
To see if the barrel is locked with
the bolt in the forward position, try
to turn the barrel in either direction. If
it turns, something’s wrong. Tell your
armorer.
5.
Pull charging handle back to cock
weapon.
8.
Keep the charging handle back to
maintain the
1
/
16
-in separation. Raise
IT'S
A
BARREL
OF
FUN
!
5.
Insert GO/NO GO gauge again.
Lug
Hole
Screw in one click
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