Home Reviews Gbtech M203 Barrel GB-Tech SOPMOD Metal M203 Outer Barrel

GB-Tech SOPMOD Metal M203 Outer Barrel

by Arnie

SOPMOD Metal M203 Outer Barrel


I started out on Project Mekut’zrar I had a high budget with which
to build the weapon with. The entire project centred around the
short M203, a similar to the SOPMOD type used by US Special Forces.
So I had 2 real options, either to cut back the Sun Projects M203’s
barrel – or buy an after market metal barrel.

Because I was after
realism I decided to go with the latter option, and fork out for
a metal barrel. Apparently there are 3 companies producing metal
outer barrels for the M203 – GB-Tech, Zeke and most recently stepping
into the arena are Guarder (I found this out the night before
my barrel arrived – damn!!). Of the 3 only the GB-Tech and Guarder
barrels are widely available (although the Guarder barrel is a
limited edition). Of those 2 only GB-Tech have a SOPMOD style
outerbarrel that is widely available. So as you have guessed I
was left with no option but to buy the GB-Tech outer barrel.

First a bit of background
on the SOPMOD kit and barrel. SOPMOD stands for Special Operations
Peculiar Modifications, and was a programme initiated by the US
NSW (Naval Special Warfare) school and SOCOM (Special Operations
COmmand) to provide a multi-function weapons platform based on
the M4A1 assault carbine. The kit includes various sights, lasers
and weapon lights but arguably the most important components are
the KAC (Knights Armament Corporation) RIS and the Colt M203 PI
(Product Improve). The Colt M203 PI is an improvement over the
original M203 (who’s design is over 30 years old!) by offering
new mounts for the M4, a lighter weight receiver, and a shorter
outer barrel. This new M203 is slowly filtering its way into the
Special Operation communities, and has been seen in photos from

Buy, Buy…
Out of the 3 places that have the GB-Tech
barrel in stock (Un Company, WGC Shop, DEN Trinity) I decided
to order it from UN
, simply because they had a new version of the
GB-Tech barrel in which came with a handgrip. All the other
websites, and even the other GB-Tech barrels advertised
on UNCo’s website only show the M203 barrel – usually you
have to bolt on the handgrip off the Sun Projects barrel.

barrel arrived along with some other parts I needed for
the project, all tax and Duty-free. But the package was
also missing 2 parts I had specifically ordered for my M933
Commando, the first time this has happened to me and I was
a little bit annoyed to say the least.

The barrel arrived in a plain white cardboard box, with
a little stick with “M203” printed on it the only indication
as to what was in the box. To be honest I was shocked as
to how short, and light the box was – did they actually
remember to put the barrel in??

Well I opened
up the box and found the barrel wrapped in a length of bubble
wrap. That was it – nothing else, no instructions, no screws just
the barrel and handgrip. I unwrapped it and gave it a close inspection;
the barrel itself appears to be made out of aluminium, and the
handgrip is made from a FRP (Fibre Reinforced Plastic), definitely
not ABS.

The handgrip
has a matt texture – much like the real M203 handgrip, but it’s
an inconsistent grey colour, which for me is a little disappointing.
The barrel appears to be anodised, and finished in a matt black.

The handgrip itself
is usually screwed into the outerbarrel to keep it secure, and
the GB-Tech barrel is no exception, but even without the screws
in the handgrip was stuck fast on the barrel. Not in itself a
bad thing – except the screw holes were not aligned.

the GB-Tech barrel has false rifling, which instead if twisting
like proper rifling it is linear – straight as a Roman road. There
is evidence in the barrel of pour moulding, as there is excess
material at the end of the rifling.

So whilst I was impressed
with the barrel, the handgrip was a bit of a letdown.

It was possibly the easiest upgrade I have ever performed.
It’s more or less a straight swap – remove the plastic barrel,
remove a few screws, add a few screws to the metal barrel and
slide it on. To remove the plastic barrel you have to grip the
M203 barrel as though you are going to load a shell, and depress
the un-locking latch. Once opened you have to push down the retention
latch at the very front of the M203’s receiver and pull the barrel
off the receiver.

Once the plastic
barrel has been removed you will need to remove the screws holding
the handgrip on (3 in total), the pins holding the guide rail
on the top of the barrel (and the rail) and the shell retention
tabs. You then need to put the parts you removed from the original
into the GB-Tech barrel. Once that’s done its simply a case of
sliding the completed outer barrel into the SP receiver.

It’s fairly straight
forward, and I didn’t need files, a Dremel or pliers to get the
job done – a refreshing change.

Once completed the barrel fitted perfectly, it lined up as
the original did. The M203’s barrel is black – compared to the
receiver’s grey which is an interesting contrast, just like the
original. I have not been able to test the new barrel with a grenade
shell because I don’t own one, but since it’s a 1:1 match to the
Sun Projects barrel in terms in internal dimensions I don’t envisage
using a shell to be a problem.

The front end of the
M4 is heavier than before, but only slightly and the added weight
makes no discernable difference to the weapons balance – its still
very front heavy.

The GB-tech barrel is a piece of Gucci kit, it’s not a priority
purchase, it’s not necessary and it’s not cheap. But it adds realism
and durability to an M203, and it is spot on if you want the SOPMOD

Is it worth
£70? No, the internal mould lines show that its not as precise
as other manufacturers kit. The handgrip looks very poor in my
opinion; the colour is off, although the texture is great. Another
problem with it is that in order to fit some of the screws you
need to move it along the barrel – and as it does so it marks
the barrel. The rifling looks good; it’s just too bad it’s straight!

I am a tad
gutted that I did not have the foresight to realise that Guarder
would be releasing a SOCOM version of their barrel after they
released the full length one.

One interesting general
note, Classic Army, Zeke, GB-Tech – all different brands, but
their products are all identical; made by the same manufacturer
in Hong Kong, just sold under different brands by different distributors.

If you are
building a SOPMOD M4 and have cash to throw around then buy this
upgrade. If you own a Sun projects M203 its worth considering
because it’s a lot more durable and robust than the ABS barrel.



M203 review by Permian

on this review in the forums

modified: Wednesday, May 9, 2001 9:37 AM copyright 2001 ArniesAirsoft