Home Reviews Kg9 Maruzen’s Interdynamic KG9 Full Auto GasBlowBack

Maruzen’s Interdynamic KG9 Full Auto GasBlowBack

by Arnie


Interdynamic KG9 Full Auto GasBlowBack

Model Maruzen’s
Interdynamic KG9 Full Auto GasBlowBack
joules (at a temperature of 20 degrees Celsius)
Length: 340mm
Weight: 2100
grams with magazine (1600 grams without)


40 rounds

Full Auto NonBlowBack

| KG9 Full Auto GasBlowBack

Firstly a big thanks
go out to Josh Horowitz of
who kindly supplied the movie screen caps and stills for this review. You
can find links to buy Big
Trouble in Little China
(I highly recommend purchasing it). –Arnie

Maruzen’s Interdynamic
KG9 Full Auto GasBlowBack

Length 340mm
Weight 2100 grams
with magazine (1600 grams without)
Power .68 joules (at a temperature of 20 degrees Celsius)
Magazine Capacity 40 rounds

Hello to Ashley Nicholls
who supplied this gem to us. Thank you.

my advice on a dark and stormy night when the lightning’s crashing,
and the thunder’s rolling, and the rain is coming down in sheets thick
as lead.

Just remember
what old Jack Burton does when the earth quakes, the poison arrows
fall from the sky, and the pillars of heaven shake. Yeah, Jack Burton
just looks that big old storm right square in the eye, and he says
give me your best shot Pal. I can take it…”

Jack Burton –
Big Trouble
in Little China

Steel history:
“The KG-9 was based on a machine gun
marketed by Interdynamic, AB of Sweden. The KG-9, as it fired from an open
bolt, was reclassified by ATF as a machine gun, due to the ease of conversion,
in Revenue Ruling 82-3 in January 1982. KG-9 pistols made before 1/19/82
are “grandfathered”, and are not considered to be machine guns.

From time to time
folks will offer “replacement bolts” for the KG-9 pistol in Shotgun
News and similar publications. Such bolts are considered by ATF to be usable
for converting a TEC-9 type gun into a machine gun, and the purchaser of
such a bolt should be aware that ATF considers the possesssion of a KG-9
bolt and a TEC-9 to be parts to make a machine gun, and thus a machine gun,
even though modification to the TEC-9 with the bolt would be needed to make
the gun work as a machine gun.

Additionally for
a time Intratec and Interdynamic sold a foregrip, or second pistol grip,
meant to be installed on the barrel shroud. After such grips were made and
marketed for a time, in response to a petition from HCI, ATF ruled that
the addition of such a grip, or possession of the gun and grip, constituted
a weapon regulated under the National Firearms Act, an “Any Other Weapon”.
It is thus not advisable to possess a foregrip and gun unless the gun is
registered as an AOW with ATF.” RecGuns

I have heard it said that the Maruzen KG9 guns – both
the BV and the GBB – are classified by some as a poor man’s way into the
classic airsoft market – I think this is a little unfair. I have also heard
it said that non-hop guns are a poor choice for a player. I think this is,
when you have the right gun, utter nonsense, but it is not really part of
this review.

Over the years I have
played with, but never owned, both of Maruzen’s KG9 copies and, as little
Ashley has found out recently, they are both excellent guns. The BV is,
especially if it has been fitted with the barrel extension kit, particularly
good and even without a hop-up is one of the best close quarters/intermediate
range guns in the external tank marketplace: easily capable of 30+ meter
hits, which is more than enough for the environment for which it was designed.
However, please take a look as Ashley’s review for more information as he
has much more experience of one than I do.

I would like to talk about the gas blowback version myself.

Maruzen have had a good
deal of successes over the years with their gas systems and, despite a number
of ‘almost’ failures with a few ground breaking system designs (such as
the M1100 shell ejecting shotgun), they have an excellent reputation here
in Japan for blowback mechanisms. This reputation was effectively established
by the little full auto gas blowback version of their old KG9BV.

how’s it work?
The mechanism itself, while a very simple
example of the open bolt “spray-and-pray” variety, is one of the most rugged
blowback mechanisms of the latter days of the Gas Market here, sharing the
reliability of the Falcon and Kokusai guns with very few of their technical

simple expedient of pulling the whole bolt back, letting it go to pick up
a bullet with the nozzle itself, ramming it into the barrel before the back
of the bolt strikes the magazine gas release is as simple as the real steel
design and just as elegant.

Admittedly, the fact
that it lacks a semi automatic option, where the older BV possesses one,
has been seen by some as a get out on Maruzen’s part to keep the mechanism
a simple as possible, but I feel this does not detract from the true magic
of the gun, which is in the overall operation and pleasure of use.

up the magazine you are immediately made aware of the design quality of
the guns components as the magazine is heavy, with a full metal body and
a huge internal gas tank. Though a loading tool is provided, loading by
hand is an easy operation and if you have one of the electric loaders that
are popular here filling up the elegant double column can be done in seconds.
Secondly, the liquid charge tank will hold enough gas for about 100 shots
in hot weather and is very well made. Darren
found two magazines for our gun from the initial batch which had never seen
gas and their seals still held perfectly after all these years.

Once loaded up and having slipped the magazine into place, it is a matter
of drawing back the silver aluminum bolt before letting a very satisfying
stream of bullets loose on your target. The weight of the bolt flying back
and forward gives the gun lovely and enjoyable recoil, which is strong enough
to be noticeable, but not so strong that one handed operation is not possible.
If you do grip it two handed though be careful, as I have taken some skin
from my thumb by holding it too close to the moving cocking handle. It also
gives off a very nice rattling sound because of its full metal outer receiver/barrel.
This is a very nice touch but does not make the gun too heavy. The rest
of the body is made form a very heavy polymer which is very easy to hold,
even for small hands, and sets the gun off nicely.

There are two safeties on the gun. The primary is just ahead of the trigger
and is of a switch variety and designed to be useable from the ready position,
but I find it impossible to flip it over using my trigger finger. The second
is simply the bolt-locking feature of the original gun and I prefer to use
this, as it seems more appropriate somehow.

In shooting the gun has some good points and a bad one:

“Damn those high power upgrades…”

The bad one can be summed up as a cooling down magazine
issue, which is not at all uncommon with liquid gas guns, so hardly worth
mentioning, especially as you have to more or less empty the magazine in
a single burst to have any real problems. However, we noticed that, perhaps
due to the very heavy double layered construction of the magazine body,
it is difficult to warm the magazines back up quickly once cooled and despite
my best encouragement Darren could not be persuaded to copy U.P. Grade’s
good example.

The good points are simply ones of good operation.
The gun has reasonable and consistent power for such a small barreled automatic
gun and while not being the most accurate, as it was not designed for use
outside of a close quarters engagement, it is good enough for the job. Other
than that it is very consistent in firing, with only one or two jams in
our test firing of 8 magazine loads. Moreover, as the jams were simply cleared
by pulling back the bolt and firing again, they hardly constituted problems.

Finally, Ashley supplied
the gun with a lovely little suppressor that, as you can see is attached
by using a special self-locking thread mechanism. It suppresses the shots
very well, but does nothing for the mechanical rattle. However it makes
the gun much longer and serious looking. This is how it will appear in our
close quarters battles from now on, especially if Ashley can get us the
shoulder stock for it.

Old guns the KG9 BV
and GasBlowBack may be, and certainly they were, in their day, in the lower
end of the automatic gun market. However, their price and relatively large
production runs now work in the favour of anyone seeking them out. If you
want to try Classic Airsoft, and everybody should have at least one classic
piece I think, these might make good choices.

The Blowback version
might be more immediately practicable for the field, but the BV version
is a little more versatile with its Semi Automatic option, much more powerful
if you fit the barrel kit to it – it can shoot at just under 1 joule with
it on – and is very, very, very accurate (non-hop guns are intrinsically
more accurate than hops at short to intermediate ranges as they have a more
predicable shot pattern – one of the reasons why we only use non hop guns
at the target club).

if that cannot convince you, just remember what Jack Burton always says
at a time like this…….

“It’s all in the




Partial translation
– Nicole Westerman.



Semi Automatic option.

for money

inexpensive even on the classic Airsoft marketplace



Silencer and Shoulder stock is all really



Very rugged. Very solid



Heavier than the new Kurtz


on this review in the forums

Last modified:
Wednesday, May 9, 2001 9:37 AM copyright 2001 ArniesAirsoft
‘Big Trouble in Little China’ imagery is copyright John Carpenter.

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