Or: "How To Be Cool For Around a Thousand Dollars"
Shane "Supergeek" Lin
The above is my personal airsoft SR-15, with GB-Tech front
end and flip sights, Systema metal receiver set, Freedom Art bipod adapter,
and Guarder red dot scope and mount.
(Other images courtesy of myself, Intruder Shop, Quarterbore.com,
Knight's Armament, UN Company, Wargamer's Club, and assorted sources)
Ah. the SR-15. I can remember when the G&G SR kit first
was released some time ago, I saw a picture of it and thought, "Jeez.
$300 for a longer version of what you already get with the Marui M4 RIS? What
kind of idiot would spend that kind of money on that." Evidently, my
kind of idiot. The real Knight's Armament SR-15 centers on the KAC Match Free
Floating RAS (Rail Accessory System), one of the latest progressions of Knight's
Modular Weapons System series. The Free Floating RAS allows for the superior
accuracy of a free-floating hanguard (by placing the stress of the handguard
and accessories on the upper receiver rather than the barrel), as well as
all the advantages of the previous RIS and RAS systems - it allows for a wide
variety of barrel configurations (including integral suppressors) which the
RAS does not support and still attaches more solidly to the upper receiver
than both the RIS and the RAS. Thus, the KAC Match Free Floating RAS has two
advantages over traditional handguards: it offers a free-floating handguard
tube, and it offers modular rails on which accessories can be hung. Neither
of these advantages are really applicable to airsoft. None of the SR-15 kits
are truely free-floating, and rail accessories in airsoft are really a moot
point considering either the cost or non-application of real firearms accessories
to airsoft. Thus, any SR-15 built would only be cosmetically superior to
a standard Marui M16A2 with the same internal components. However, having
spent this ridiculous amount of money in making my rifle look "pretty,"
I'm rather content with the final outcome. If the transformation of a typical
AR to the rifle you see above is worth the price though, is completely up
for debate.
Choosing a SR-15 Conversion Kit
Several companies make SR-15 conversion kits which replace the
entire front-end of Marui Armalites. At the time of publication, there are
three major type of RAS available, produced by GB-Tech, G&G, and Classic
Army. The Classic Army and G&G designs are similar in design and shape,
while the GB-Tech is different. The most obvious difference at first sight
is of course the barrel. Whereas the CA and G&G kits have a black finish
that matches the handguard, the GB-Tech kit has the matte satin finish that
is most commonly associated with the SR-15. However, the barrel finish itself
is not crucial, and really a matter of taste, since the free floating handguard,
after all, does have the ability to support many types of barrels. What is
important though, is the design of the handguard itself. In many ways, these
are similar. Both are made of machined aluminum. Both have standard rails
that are not quite mil-spec. Both have visible and separate gas tubes. However,
while at first the Classic Army/G&G design may look similar at first glance
to the GB-Tech, there are distinct differences between each of the handguards,
and between the real Knight's version.
As can be seen, the holes in the actual handguard are evenly
spaced on the G&G, and not so on the real RAS. The number of these holes
are also different. The GB-Tech replica remains true in these regards, or
at least truer than the G&G. It may be of interest to note that the
G&G kit is significantly simpler than the GB-Tech kit, which consists
of quite a few components. The final impact as a result of however is minimal.
Beyond the RAS, the most contrasting difference on the G&G replica must
be the gas block and front sight assembly.
|
|
|
|
Top: Real Knight's gas block and front flip sight
Bottom left: G&G, right: GB-Tech
|
The G&G gas tube is similar to the SR-25 design, which has
the top and bottom rails designed to take the flip-up front sight. The Classic
Army design is similar. The GB-Tech design however, is consistent with the
original Knight's armament design, with the ring supporting the gas tube held
in place by a hex screw.
Another area of difference are the all-important trademarks. While
G&G and Classic Army (Yick Fung ltd) has opted to put their own custom
trademarks on the handguard, GB-Tech has true Knight's Armament trademarks,
even with the correct phone number ((561) 562-5697), though there are several
minor errors (for instance, "VERO BEACH ,FL" instead of "VERO
BEACH, FL" ).
The other side of the GB-Tech handguard is marked with the words
"M-4 Sniper R.A.S." and the KAC parts number (the correct one! P/N:
99167), and the conversion kit is usually sold as such. While it may seem
rather odd that "M-4" is mentioned, as it is the longer RAS handguard
not expressly designed for use on either the Colt M4 Carbine or the SR-15
M4 variant, further research has shown this to be accurate. As quoted from
Quaterbore.com: "Early versions of this tube were labeled 'M-4 SNIPER
R.A.S.' which apparently upset Knight's legal department so all later models
were marked 'M-4 MATCH R.A.S.'"
The GB-Tech and G&G kits cost a similar sum, while the Classic
Army model is significantly cheaper. For the price, the Classic Army and G&G
kits are packaged with the front flip sight, while the GB-Tech kit is not.
And while the CA and G&G kits use a standard M16-length barrel, the GB-Tech
design does not, and is packaged with a special barrel (more on it later).
The G&G kit is heavier than the GB-Tech, and while both are obviously
black, neither perfectly replicates the finish of the KAC handguard.
In comparison, the GB-Tech is thus a far more accurate representation
of the original Knight's armament design, due mostly to the curious deviation
G&G and Classic Army chose to take with the gas block but also to numerous
minor things. Let's compare:
|
|
 |
 |
 |
|
(Click to enlarge)
Top: January 2002 issue of Guns & Weapons For Law Enforcement,
with what is no doubt a real SR-15.
Middle: Real Knight's FF Sniper RAS with upper receiver.
Left: GB-Tech kit. Err.. I don't know who this guy is, but he's
got the same exact setup as me *cough*
Middle: G&G Kit in an airsoft shop, sans the gas block assembly.
Those crazy Hong Kongites.
Right: My good friend Dax Hammond, with the CA SR-15/M16A3 he
won at Operation Reindeer Games.
|
And so, given these minor details, the most realistic of the
three different conversion kits is no doubt the GB-Tech one, though of course
the G&G and Classic Army preserve the general "look" and "feel"
of the design. They are also technically better deals since there is no need
to purchase the rather pricey front flip-up sight, especially considering
that the Classic Army kit retains really pretty good build quality while being
nearly half the price of the other two kits. However, for the die-hard collector
and realism nut, there is no other choice than the GB-Tech kit, which combines
exceptional quality and excellent authenticity, unfortunately, with a high
price. Mine was purchased with the entire earnings of a sale of an upgraded
Marui MP5A4.
That said, the GB-Tech has one major problem beyond price: the
irregular barrel may present problems. My barrel at the very least was not
constructed of proper tolerances, and I suspect that has too large a diameter.
Thus, air readily flows between the BB and the barrel walls, producing severe
inaccuracy and low power. If I remember correctly, the gun was shooting 1
foot groups at about 15 or 20 feet. I tried to fix the problem by replacing
the hop-bucking to Guarder, then KM, and finally Systema, but to no avail.
Finally, I tried to replace the barrel with a Systema M16 barrel. However,
the M16 barrel is 2mm too long for the kit and a bit too thick to fit, and
given the tolerances of the GB-Tech barrel crown, that small difference would
cause the barrel to decapitate the hop bucking edge against the hop chamber.
Finally, I had to sand down the brass of my Systema barrel, which fixed the
problem. My gun achieves normal groups now. Not everyone has reported this
problem, and certainly it may not manifest itself in every barrel. But my
case proves that it likely happens with some frequency, and that a replacement
barrel should be considered regardless of what happens with the GB-Tech barrel.
Adding an additional $25 to a nearly $300 conversion kit is not much, but
it would have been better if the standard M16 barrel would fit.
A Realistic SR-15 receiver Set?
Okay, so now we've got half of the rifle. There are quite a
few aftermarket metal receiver sets to choose from. The only one in semi-mass
production model which specifically carries the SR-15 name is the DTP (Den
Trinity Products) SR-15 Receiver Set. By most reviews, it is a very skillfully
crafted and made stronger than the vaunted Systema bodies. It is heftier,
and seems to have superior fit and finish. Unfortunately, it also looks nothing
like the receiver set that the real SR-15 uses. Instead, with its flat, blocking
profile and lack of a forward assist, the DTP SR-15 receiver is very similar
to the Knight's SR-25 receiver set, but instead of the .308 magazine well,
it retains a smaller .223 well for use with standard M16 magazines. I'm unaware
of a receiver like this in the real firearms world, though several retailers
are selling custom SR-15s using this reciever set on a variety of front end
conversion kits. It is clear from the pictures of the real SR-15 above that
it uses a more or less standard external receiver.
|
|
Top: Knight's Armament SR-25 Mk11 Mod 0 version for US Special
Forces
Bottom: DTP "SR-15" receiver set. Note similarity of design,
as well as difference in magazine well. |
The only other widely available product that is still somewhat
applicable is the Systema SR-16 M5 receiver set, which of course follows the
convention of the intentionally-erroneous naming of the Tokyo Marui AEG. At
the very least, it's fairly plentiful, comparatively inexpensive, and almost
accurate. The trademarks are printed and not engraved, but reportedly the
process is very clean. The KAC logo looks quite excellent and the receiver
set is accurate in almost all other ways. This is probably the best possible
choice considering the final alternative. Maybe scratch out the bridge in
the number "6" to make it kind of look like a "5?"
Note that I've mentioned "widely available" for the
previous two products. And while the Den Trinity receiver set maybe a bit
more scarce than the Systema, it still remains more or less true. However,
there is one more option up for consideration. UN Company, a quite reputable
Hong Kong airsoft shop, offers custom engraved Systema receiver sets, including
Knight's SR-15 M4, SR-15 M5, and SR-15 Match receivers sets for $280 - $100
more than the standard Systema bodies.. These look very well done, but availability
seems to be very low, with each receiver individually serial-numbered. At
the time of publication, the M4 and M5 receivers were both sold out, and given
the nature of these things, there will likely be little chance there will
be more made. However, the mere fact that it is the most accurate of the airsoft
receiver sets makes it disproportionately desirable, despite the fact that
it is really, in essence $100 spent for a single changed number. If one is
made available for a decent price, by all means, grab it.
 |
| Obviously, images courtesy of UN Company |
Other Considerations
Iron Sights
To complete the look of the SR-15, regardless of how useful
they really are given some sort of rifle optics, iron flip sights are required.
G&G sells their flip sight separately of their conversion kit, though
it remains rather visibly different from Knights' design. The GB-Tech sight
is a faithful representation, down to the different grayer color of the left
rail hook and bolt, though it, like the Knight's version, is a bit difficult
to flip open. Finally, FIRST Factory produces their own rail flip sight as
part of their Nitro.Vo series, with a neat spring-loaded mechanism and windage
adjustment. Again, the GB-Tech sight remains the most true to KAC, different
only in that the rail hooks are equal in length. All the flip front sights
are actually rather pricey, quite a bit more than one would expect for just
a few pieces of machined metal, but there isn't really a choice, for the sake
of aesthetics, but to put a front sight on.
The standard Marui flip rear sight sold individually or packaged
with their SR-16 AEG is a good replica of the Knight's flip sight, and an
inexpensive option, considering far more expensive ARMS and Bushmaster products.
The base is different, and larger, but still the general style of sight is
retained.
|
|
 |
|
Top: Knight's rear site with peep sight adapter
Bottom: Marui rear flip sight
|
Optics
Obviously, any scope or reflex sight that can be used for a
typical flat-top AR will work with an SR-15. However, the limitations of airsoft,
as well as the potential inaccuracies in the sights may mean that some forms
of optical sights will be less effective. In most pictures of the SR-15, we
see a tactical riflescope, typically around 40mm, since after all, the SR-15
is a "sniper" rifle. Having said that, a low magnification scope
would have little use on an airsoft SR-15 if the player wishes, as I do, to
keep the gun under 400 FPS to conform with local regulations. One is easily
enough mounted though, as seen here, with my beloved SIIS 4x40mm, on made-for-airsoft
ultra-high 1'' rings from Hong Kong.
(Click to enlarge)
My immediate second choice was to go for a EOTech holosight,
which uses laser Heads-Up Display technology to display a hashed circle reticule
instead of the traditional dot. This was my first foray into relatively upper-level
optics, and I was very impressed with the unit. In fact, it was nearly the
perfect sight for the SR-15 - lightweight, very capable, sleek, and it actually
was perfectly in-line with the flip sights when mounted directly to the flat-top.
However, the cost of the sight was a burden at more than $230, and there was
no way to protect the front lens from BB hits since I didn't want to destroy
the low-drag profile of the rifle with a Freedom Art lens protector. So,
it had to go. I sold it and decided to pick up something a bit cheaper.
(Click to enlarge)
After considering the Tasco PDP5 4-reticle and the Tasco Accudot
30mm, I decided to pick up a Guarder red dot sight from my friend "Swissjak"
Bryan, who had won it at the Operation Reindeer Games raffle. Again, this
decision was propelled mainly by aesthetics, since I've been a fan of Guarder's
pseudo-replica of the Aimpoint since its release. It looks like a generic
Aimpoint without the battery casing, a but smaller. Certainly, it's a low-fidelity
representation, but the price difference, and the terrible reports on the
first-generation TGS and Marui replicas leave little other option. The cantilever
mount completes the look. All in all, it's quite a nice optics setup for the
SR-15.
(Click to enlarge)
Bipod
It's a sniper rifle! It HAS to have a bipod! As can be seen
through the various pictures of my gun in this guide, I own a Versa-Pod 2
bi-pod that I *sometimes* use on my upgraded APS-2. While I may sometimes
take a picture of it on my SR-15, I'd never take it into the field with it
on. There's simply no point in airsoft, with engagement distances of less
than 100 meters. The specific bipod of choice is of course another very personal
decision. Some people like the Harris, whereas I prefer the Versa-Pod. What's
more interesting is bipod mounting options, since as anyone can see, though
I don't use a bipod on my SR, I do use a Freedom Art RIS bipod adapter. I
believe it adds a bit to the overall aesthetics of the gun. Ah, the mysteries
of the universe.
The GB-Tech conversion kit is packaged with a screw-in bipod
mounting stud. This screws into the many holes in the rails of the gun and
though it is almost certainly expressly for the purpose of mounting a bi-pod,
I could not fit my Versa-Pod adapter on without heavy sanding of the top of
it. Having accomplished that, I moved the stud over onto my APS-2, and got
a Freedom Art bipod adapter in a trade. Despite the strange mounting system
it uses, the adapter does its job.
Closing Notes
Beyond what I've mentioned here, the actual internal components are of
course up for the reader to decide. this guide, as with the entire SR-15 project,
is almost completely cosmetic in nature. What sort of batteries or springs
a gun should have is irrelavant. What type of front flip sight is a matter
of personal respectability. I'll end off this guide with just a quick overview
of my SR-15.
The gun actually started out as a Marui M4A1 RIS, so the only
componant left over is the gearbox, motor, grip, and assorted pins and screws.
I rewired the gearbox and switched to a full stock and replaced the cylinder
to accommodate the longer barrel. There was no need to upgrade the gears, since
it's just a PDI 170%. I'm using an 8.4v2000mAh battery, and getting a pretty
good rate of fire with it.
Internal upgrades
- Systema Tightbore Barrel
- Systema Metal Hop-Up Chamber
- PDI 170% Spring
- Guarder Spring Guide with Bearings
- Guarder Polycarb Piston
- Guarder Piston Head With Bearings
- Guarder Bearing Bushings
- Systema Type-0 Cylinder
- Systema Hop bucking
External components
- GB-Tech SR-15 Conversion Kit
- Systema M4A1 Metal Body (left over from when it was an M4)
- Freedom Art bipod adapter
- Guarder Cantilever mount
- Guarder Red Dot Scope
- Versa-Pod 2 Bipod (when needed for display)
- GB-Tech Flip-up front sights
- Marui Flip-up rear sights
Additional Images
(Click to enlarge)
