Home Projects Custom Svs Sv Tuneup SV TuneUp

SV TuneUp

by Arnie

by Matt
(aka MobiusStrip)

The Western Arms series
of 1911 Hi-Cap/SV pistols, are in my humble opinion the ‘best’ Gas
Blowbacks out there. I say ‘best’ in inverted commas because they
still can be improved upon much like the real steel.

What follows are the methods I used to improve things from a reliability
and functioning point of view, although a lot of these mods are
to ensure smooth operation over a long period of time. This is not
an excuse to skip regular maintenance procedures.

mag screw

A common problem, part # 8044 slowly comes loose after repeated
use jamming the mag in the gun, this used to happen to me before
I knew what to do, and I still see it today with other folks guns
on the odd occasion. To stop this, remove the screw, wipe the screw
hole with a cotton bud to get the worst of the residual oil out
then apply Loctite 243 Threadlock and screw back in.


If I had a penny for every time I heard about loose mags! I have
never had a mag drop out/rattle so much as to give away my position
or any other attributed malfunctioning problem associated with this,
in fact it wasn’t until I kept reading about it, that I checked
my own to see if I had missed something. Even on the real SVI I
had, the mag fit would vary depending on how many cartridges were
in the mag, from loose to snug. However ‘if’ it really bugs you
then stick some plasticard (available from 0.5mm) and stick it inside
your magwell – but I stress I do not recommend this at all.

I assume WA
have picked up on this as later SV’s have a new Mainspring housing
design that protrudes slightly into the mag well to lessen the ‘now
infamous’ mag rattle which will please those that were concerned
about it.

White shavings in chamber area
Quite a lot of people complain of the “swarf” in the chamber
area of the SV’s although some mags can have sharper lips than others
this appears to be a minor problem. If you are getting BB’s sometimes
sticking in the mag lips due to tight tolerances, de burr the mag
lips by wrapping some 800grit wet and dry paper around a small diameter
rod, insert into the mag lips where you would push in the BB’s ,
and gently smooth off any casting marks/sharp edges. repeat with
1000grit to finish off. N.B. In the photo white paper has been used
instead of wet and dry paper for clarity.

Hammer spring /
Mainspring strength

Sometimes, ‘light strikes’ may be experienced, these will manifest
themselves as the hammer falling, maybe with enough force just to
let enough gas out to spit the BB out of the barrel, but not to
cycle the slide. Normally this is due to gas of a higher pressure
than the 134a recommended by WA meaning that there is insufficient
hammer tension to overcome the mag valve and gas pressure within
the magazine. To cure this a spacer in the form of a thick washer
is needed on the mainspring. I have used a 2mm spacer with an outside
diameter of 6.3mm and an inside diameter of 5mm, which has cured
all of the guns I have seen except one that required a 5mm spacer.

Alternatively you can
purchase a stronger hammer spring such as the IS/Guarder Enhanced
Hammer and Recoil Spring set both are 150% strength. eThis picture
shows original hammer spring and IS Guarder hammer spring (150%)
together for comparison.
As discussed on the Metal Slide fitment Guide, I have tended only
to use the hammer spring.

Sticky Right hand

It has also been known on occasion when the Right Hand Safety is
switched from safe to fire (i.e. for left handers) for the left
side safety to catch, so that the safety cannot be applied smoothly.
This can be cured by a slight chamfer under the l/h safety block
(the block that sticks inside the gun on part #126)


Barrel comes loose
Very common this one, I have had this myself on almost every one
of the SV pistols I have had, and I have seen enough sheared barrel
hoods to know that over-tightening is not a wise move. It is possible
to buy the Guarder or Sheriff “breech cover” aka barrel
hood, which is metal, and then a tiny drop of Loctite 222/243 could
be used as it is metal to metal, (222/243 cannot be used on plastic),
but if you are sticking (no pun intended) with the standard parts
then Cyanoacrylate adhesive (superglue) is one of the ways to go.
It should be applied sparingly to the very end of the barrel ‘tube’
with the threaded end, around its lip. then quickly screw onto the
Barrel hood/breech # 5 and you have a solid unit that can still
be taken apart due to the fact that the standard WA barrel hood
is plated with a very high sheen and therefore the glue also acts
like a gap fill and makes everything nice and solid whilst being
able to be separate the two parts.

The second, and easier/safer
method, especially for those who do not wish to dabble with superglues
on their pride and joy, is to use PTFE tape.

This wrapped a few times
around the exposed thread on the plastic chamber cover with provide
enough grip so that when the outer barrel is screwed into place,
it will stay put. I currently tend to use this method myself these
It is interesting to note that the most recent part # 5’s (Barrel
hood) that I have seen, have been a lot tighter than previous examples
when screwing into the barrel body, so maybe WA have decreased tolerances
here to stop any problems, however still examples come through that
are in need of attention.

Guide rod loose
Often the two part guide rods can come loose over a period of time,
and although never actually likely to unscrew completely without
being noticed, one can never prepare for that night game where you
cannot check everything! A simple 5 minute job to use Loctite 243
sparingly on the guide rod thread where it unscrews will save any

Non-Leak-System (NLS) – Removal
This is referring to parts 105 and 109 in the magazine. In a nutshell
these parts enable the gun to be fired at obscure angles without
liquid gas (in the form of a cloud) coming out of every orifice.
In plain English -you can fire the thing upside down or sideways,
and there will be no gas squirting out of the end of the barrel
or ejection port etc. It is possible to remove these parts to give
a bigger and therefore more stable gas supply especially during
rapid fire – (in fact Western Arms themselves remove them from the
full auto Infinities for just that reason). The mag now has a larger
reservoir and therefore the “cool down” effect is lessened
during rapid fire. Also, It is now possible to get 60+ shots from
a mag, instead of 45 or so. I do not recommend doing this as the
mag tends to only fire the original 30 at full power then the fps
drops off. But you get the point – more gas in the magazine.
As I don’t really spend a lot of time shooting my guns sideways
or upside down, I have removed these parts from all my SV mags –
no more gangster sideways shooting for me then ^_-

Should you want
to carry out the modification of removing the N.L.S.

Release all the gas – by firing off BB’s
To take apart the mag: push in the nib of 850 through the base plate
Slide base plate forwards
Push out pin 47
Remove 46
You will see the brass tube inside, you need to get a coat hanger
and make you self a 90 degree bend along a flat, then cut it, so
that you have an “L” shape with a tiny end that can put
up the tube, and carefully hook the entire unit out.

Now simply assemble in
reverse order leaving out #105 and #109.

Setting the HOP
WA SVI HOP is fiddly to adjust, no question about it. To help yourself,
make sure that the barrel is clean to start with as you don’t want
any dirt or blobs of oil messing up your finely tuned HOP.
For a starting point, take the barrel out, look down the breech
end. Notice the fixed HOP bump at the top of the barrel. Now match
the bottom adjustable HOP “bump” so that it mirrors the
amount of the top fixed HOP.
N.B.If you shine a torch down the barrel, you will see that the
top fixed HOP part is black and the adjustable bottom part is white.

Now you should have an approximately even amount showing top and
bottom. This is a good starting point, from here I set my guns up
using .20’s turning the HOP screw an eighth at a time, as soon as
you get just one BB whipping up, back it off an eighth. Then use
.25’s at that setting – that should take care of any other variables

Don’t worry you’ll be okay with .20’s, but obviously a heavier BB
will be more stable/consistent through the HOP (when set up initially
with .20’s) :)

Part 88 Blowback

Now this is a problem that I see reoccur more and more regularly.
The slide jams during blowback – I have seen guns that required
a nudge on the rear of the slide to re-seat the O ring, others,
the O ring had ridden over most of its groove, thus jamming the
gun solid. Replacement with a higher quality part is the answer.
The problem is that the Blowback O-ring, Part 88 in the WA manual,
is actually too loose a fit, or is not of the correct ‘shore’ hardness.
That is to say….it is when using green gas ^_-.
A good quality tighter O-ring, stops the problem of the oversize
duff one riding over the edge of its groove thus jamming as described.

The correct size needed
is 13.3mm outside diameter, with an inside diameter of 10.1. This
gives a section thickness of 1.6mm.
Since retro fitting these, I have never seen this particular problem

Basic Lubrication
and it’s role in preventative maintenance

Now then do you have a manual? You can follow the WA procedure in
there, and it will give you an idea of the points to lube. The thing
is, I don’t actually religiously lube mine, just when they need
it, (yeah -that old chestnut ^_-). What I will cover is *Field Stripped
Oiling only* not the full Monty, as that is a major job (takes less
time to do than type for a start ;))

Okay, first thing is get the correct lubes. I use Loctite Superlube
OIL pen, Silicone SPRAY OIL and Silicone GREASE. Make sure that
the grease you buy does not contain tons of solvent as this can
attack rubber seals. I have used the following procedure for years
with no problems. Generally, you need to lube any moving parts,
look for signs of wear etc.

*hope you know the nomenclature…* :)

Slide off, barrel and spring/guide rod out.
SLIDE = SUPERLUBE OIL = Inner slide rails/ Blowback engine O ring
and rails of Blowback engine, also a drop of SLO into the hole with
the rocket valve/ drop of oil on you finger tip, rub this around
the muzzle of the barrel, then over the locking lugs on the barrel
hood. SLO to the underside of the chamber where it runs inside the
frame and where the barrel hood pivots over the fixed barrel. Guide
rod and spring, a couple of drops (SLO) should do it. Also don’t
forget the part at the front of the slide that runs inside the frame
(e.g. the couple of bumps on a 5 Limited slide)

SLO = Slide stop roller.

FRAME – SLO =Rails/ upper disconnector/ (drop) mag valve sliding
plate catch (drop)/ Frame rails (belt and braces there ;))/ firing
pin. Hammer face.

BARREL Spray a half second burst of Silicone spray down the HOP
end of the barrel, then with the gun assembled, fire off a couple
of mags worth to blast out any of the excess lube from the O ring
in the blowback chamber. With a BB in the chamber (slide forward
-mag out), gently use a Marui cleaning rod with tissue as per Marui
specs/dimensions in the manual to clean out the excess lube. The
BB in the chamber stops you going through the HOP too far.

MAGS – Remove magazine upper valve and use Silicone grease on the
O-rings -it seems as if they come pretty dry as standard. Personally,
when I buy a new SV, I *completely* strip the gun down and tune
the insides when putting it back together, part of that is the application
of Silicone GREASE to *all* the rubber seals on the mag, heavily
applied to the square seal/ring at the bottom. Not had a leak yet!
When the gun is assembled and suspect a valve may need lubing (on
a handed in gun for example) a quick cheat is to use SLO and flood
the back of the upper valve and work it in or out. The SLO will
work it’s way down.
Part 57 mag gas route packing, use a smear of Silicone grease.

When it’s all lubed up put a couple of mags through it then wipe
off the excess lube. Keep the inner barrel fairly dry and it will
eliminate any problems of excess lube affecting the HOP.

I get my lubricants from http://rswww.com

Silicone Oil aerosol
– general cleaning, barrel etc

Silicone Grease 117-9983 – good for ‘sealing O rings’ such
as those on mag base pads etc

Loctite Superlube Oil pen 184-7945
– general, metal to metal
and plastic to plastic…and metal to plastic, not to mention on
some moving parts such as valves and their respective high repetition/open
-closing O rings.


– the offical homepage of WesternArms
Voigt Inc
– the official homepage of SV

the offical hompage of SpringField Armoury
– the homepage to Sheriff in Japan

Last updated:
Thursday, February 13, 2003 10:30 PM

Except where listed, all contents are Copyright 2003 ArniesAirsoft

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