Update for Rear Iron Sight - GSG has made an adjustable rear iron sight for windage and elevation.  They are available now.

Since the "Original GSG-5" rear iron sight has no elevation adjustment, a replacement has been found for those looking to upgrade.
my2cents found the ICS airsoft rear sight has a basic elevation adjustment. The drum is threaded like on a real HK but it just screws up and down on the base with a detent stop at each position. So when you turn to a different position you are changing the elevation. Not as nice as the real HK sight but it does give a basic elevation adjustment and is a drop in replacement on the GSG5. It is all metal and similar to the original sight in quality. The ideal solution will be to fit a real HK sight to the GSG which I'm sure someone will do very soon but this is a drop in replacement. Lock down screw and windage screw are the original GSG parts. It is setup like a G3 drum so each hole is the same size and drilled at a diffferent elevation.  The drum appears to made out of blackened brass.
Purchase - Blazing Toys - Part MP-31
[

You can use a real Hk sight and not mod anything but there will be a gap underneath the sight base. You could use a piece of plastic or rubber to shim it and fill the gap if you don't want to mod your receiver.
The big issue could be windage as there is almost no left windage unless you mod the receiver. If it zeros and you don't need any more windage then you are good. You can use a small washer on the original GSG windage screw so it will fit the HK sight snug. The slot in the HK sight is much wider than the one in the original.





If you need more left windage you would need to cut some off of the post as shown below.

Optics and Mounts

For some Airsoft Optic Reviews - Click Here

bicho with a low profile mount and a eotech.  the mount came with the gun from the factory.



jeffg87 with a low profile mount and a Burris Fastfire red dot. Purchase - Optics Planet


jackal2001 with a G&G Low Profile Mount. Purchase - Redwolfairsoft
G&P Model 121 Red Dot. Purchase - Redwolfairsoft
Sightmark Multi-reticle Reflex Sight. Purchase - Sportsmansguide
I highly recommend this G&G mount, it drops right in and fits perfect!  The ultimate LPM, made of aluminum.  With no optic on the mount you can still use the iron sights.





Ripnrob with an extended low profile mount, aimpoint clone, and a surefire scout light.
Heavy modifications with a dremel were needed for his mount on the underside.  It didn't have the cutout for the raised section on the GSG itself.



Icarus with a NcStar DMP5 1 x 20 Red Dot with a built in co-witness mount. Purchase - Optics Planet

Airsoft Stocks

Most airsoft stocks will work.  Some may need to be modified.

Ripnrob with an ICS airsoft side folder. Purchase - Evike  
When folded, it completely blocks the ejection port.
Only modification needed was the pin hole needed to be reamed out a tiny bit in order for the pin to fit.


soup-nazi with a Classic Army B&T Type MP5 folding stock (Model A189P). Purchase - Airsoft Extreme
He stated that it fits with no mods needed only a little light tapping to get in on the receiver.  He also noted there is no means to "lock" the stock when it is in the folded postion, but the friction of the hinge helps it stay folded.  It will fire and eject brass when the stock is in the folded position.
I personally purchased one of these stocks and I did have to remove about 1/16" from the top inside with a dremel.  It was just too tight, even with applying some wheel bearing grease.  It does lock up 100% solid with no wobble anywhere on the stock.  It is also a very solid feeling stock.




EchoAngel17 with a Classic Army Collapsibe Stock (model A030M) Purchase - Cobra Airsoft
No modifications needed, slips right on.  Full Metal Construction, Locks in 3 positions - Collapsed, Midway, and Fully Extended.
As we found out with other people, when the stock is fully collapsed, it will partially block the ejection port.  This will have no effect on ejecting brass.  The brass still clears the rail of the stock and functions fine.
The wire sling attachment that ships with the stock will not work with with the weapon.




STOCKS THAT WILL NOT WORK OUT OF THE BOX


G&G Brand Airsoft UMP side folding stock will not fit out of the box.  The top area is too tight and needs to be dremeled out.  It may not be worth the effort.  Picture taken by JRX35.

Real H&K Stocks

Following information provided by decodeddiesel

OK so today I received my HK parts from HKParts  I ordered a number of things including a used A2 stock, 2 small pins, one large pin, and a green HK sling. Just a quick note about hkparts.net, they ROCK!!!. All items were sent out the same day and I received them in 2 days! Great Job! So anyway, onto the how-to.

First some compairison pictures between the HK stock and the GSG-5 stock. Here we can see the GSG stock (above) and well loved the HK stock (below). What you can't see it the amazing difference in durability between these stocks. The HK stock itself feels like a weapon, it is very stout and feels great. By comparison the GSG stock feels like it would break to pieces if I dropped it.


Comparison shot of the mounting points. Real HK on the left, GSG on the right. Note the differences between the "rails", this is the ONLY area on the stock that requires modification.


The first step was to drill out the stock pin mounting hole for the HK "large" pin. I measured the pin to be 0.272" with a set of calipers. The next size up on my drill index is the "J" bit, measuring 0.277". The through hole in the receiver is plastic, and the TiN bit I used zipped through it like butter. I wouldn't even bother trying to step-up the hole size, it's so soft, and so close so as not to matter.


Next thing is the ONLY grinding step required in the whole process. Looking at the right, or "ejection port side" rail on the HK stock we can see it's a little too tall to fit. Enter Mr Dremel tool. I used a grinding drum, at medium RPM. The HK stock material is tough, but grinds well. I just shaved a little at a time constantly test fitting until the stock fit.



Here are the grinds. I did go a LITTLE too far, but the stock is still VERY snug and has zero side to side wobble. I did notice a very small amount of up down wobble. Honestly though, there's such a small gap I seriously doubt it will bother me while firing.



I may "bed" the stock with JB weld if the wobble really bothers me, but compared to factory stock it is WAY more stable. The pin I found is a snug fit, but thats the way I like it.


Finished pic:

Airsoft RAS/Forearms

When trying to install different brands of RAS/RIS on, it may be necessary to remove and replace the long set screw that holds the barrel from rotating and acts as a brace for the standard handguard.  You can replace this set screw (pictured below, left) with one that is 10/32 pitch and 3/8" long (pictured below, right).  It will then sit flush against the bottom block.  Pics from Ripnrob.


Ripnrob with a G&P Knights Airsoft RAS (Model GP102) (heavy modifications to the collar needed) Purchase - eHobby Ebay
Pictures of the unmodifed parts and collar.



Collar is held in place my that metal bracket into the RAS.


After heavy cutting and filing and giving it a coat of black spray paint.  You can see how much material compared to the factory collar was needed to be removed.  You can now see how the collar goes up and into the slots on the reciever.


One piece of the rail had to get cut off in order to clear the ejection port.



With the rail panels and VFG installed.  Great job, just awesome!!!


Heineken with a Nitro brand RIS forearm. Purchase - Trinity Airsoft
The stock front handguard screw is a bit long and may need to have a lock washer put on to take up the play in the forearm.  
The tabs may need to be bent in order for it to sit strait.



ADOR with a CA MP5 Tac Light & Handguard (Model A127P). Purchase - Airsoft Extreme
Perfect Fit, no modifications to the forearm, but the screw that goes into the barrel housing needs to be replaced.


01coltcolt with a Classic Army MP5 RIS. Purchase - Trinity Airsoft
He had to cut the rail panels off to clear the ejection port. Slight mods are needed, info posted below. He also stated that the camera flash made it look grey when it is not.


Mods needed for the CA to fit are minimal, pics by TDKNC


There is a set screw on each side you tighten to "squeeze" the collar, which gives the CA a rock solid feel.

Airsoft Long Top Rail

JohnStoner did the install by notching the charging handle, try to keep the mocking to a minimum as I haven't gone to it with a fine file yet. The important thing is it functions. You do need to do some dremeling/filing so the charging handle can stay in the locked back/up position.

It comes with a replacement front site and you need to remove the rear site to install it. The installation of the front site is optional, I chose not to. Another member here a  install. Not sure what it involves.

The small blocks of metal that clamp onto the gun can be over tightened and break. I replaced mine with a low pro clamp off a $15 mount when one of mine broke. To me it's a complete change to the look of the weapon, though expensive it's awesome. If you can find one in stock I would fully support the decision to purchase. I enjoy it a lot, holds zero no problems with the fakepoint I use.

Rail Sleve by Laylax - Purchase - Trinity Airsoft

So far the only company that I am aware of that had plans right from the get-go to come out with a bunch of different options for hosting a suppressor.

This information was posted by Kel

GSG-5 with SBR modification, showing an early pre-production (final ones are blued) Gemtech GSG adapter nut:


GSG-5 with SBR modification, Gemtech adapter nut, and Gemtech OUTBACK series suppressor:


GSG-5 with SBR modification, Gemtech adapter nut, and Gemtech 3-lug (shown with MP5 9mm RAPTOR-II suppressor)


GSG-5-SD legal length, non-SBR, permanently installed dedicated suppressor bringing overall barrel length to 16":


GSG-5-SD Suppressor Unit:




The can can be picked up on it's own or as part of the GSG in order to drop costs by making it an extension of the barrel and avoiding double stamp fees.



UPDATE FROM GEMTECH
The GSG-5SD will be available on a Gemtech supplied GSG-5 Rifle, permanently attached. MSRP $1,195 for the complete package. Final design work, testing, and production of the first batch of rifle/suppressors is beginning. Target release date is May 2008.
Adapters will be the same price as our P22 and Mosquito adapters at $45 MSRP. If you send your Form 1 SBR rifle to Gemtech we will cut and recrown your barrel and install the adapter for $150.

Owen M.
Gemtech


5/13/2008 Just FYI, we at Gemtech ended up using a different specification for shortening and profiling the GSG barrels for our adapters. The ones we did in '07 were based on only having one sample of the carbines, and since we've had over a 100 of them come in, we've revised things a bit.
Any adapter shipped prior to last week will follow the original install specs, new adapters will have this instruction sheet:


8/14/2008 Gemtech has come up with another method of attaching suppressors and is a thread on adapter.  Here on the instructions:


The price on the Gemtech GSG-5 Suppressor Adapters is $45 each.
Gemtech currently does have the GSG-5 adapter nuts in stock, clients may order directly via phone with V/MC, 208.939.7222 9-5 MF MST.


Gemtech GSD-5 (2 stamp gun) ($1,195 or TBD)



Gemtech GSD-5 (1 stamp gun with perm attached suppressor.  OAL 16") ($1,195 or TBD)


Gemtech Drop in SBR Barrels.  More info Here


Gemtech 3-Lug Adapters for GSG-5 Pistol.  More info Here

AFTERMARKET SBR BARRELS

dspd204 has aftermarket SBR Barrels over Here in the EE
These barrels work in conjunction with the Gemtech Suppressor Adapter.

Please refer to the ad in the EE for further information.










How to tell the difference of what Generation GSG-5 you have.

OFFICIAL GSG ACCESSORIES

Some places that have official accessories:

Cope's Distributing

HK Specialist

AIRSOFT ACCESSORIES


Redwolf Airsoft - Probably the most popular airsoft retailer
www.redwolfairsoft.com/redwolf/airsoft/Home

Airsoft Extreme
www.airsoftextreme.com/content/

Airsoft Global
www.airsoftglobal.com/

Trinity Airsoft
www.trinityairsoft.com/default.aspx

UN Company
www.uncompany.com/

Dentrinity
www.dentrinityshop.com/index_ie.jsp

WGC Shop
www.wgcshop.com/

War 4 Toys International
www.airsoft-war4.com/

Tokyo Model Company
www.tokyo-model.com.hk/ecshop/index.php

Airsoft GI
www.airsoftgi.com/default.php

Cobra Airsoft
www.cobraairsoft.com/ - some have reported problems ordering from them.

Evike
www.evike.com/Merchant2/merchant.mvc?

PowerEdge USA
www.poweredgeusa.com/

Shorty USA
www.shortyusa.com/

AirSplat
www.airsplat.com/

Complete Replacement Screw Set

HK Push Pins for the GSG

Aftermarket Stainless Steel Barrels (SBR or Long) and suppressor adapters

Gemtech Drop In SBR Barrels and 3-Lug adapters

Swarfworks GSG Suppressor Adapters and Other Accessories




40 Round Strait Mags - Warning, Fraud Alert!  Do not order from this website.

This is just some info for those wanting to fill out a Form1 to make their GSG into a SBR.

Box 4a:
German Sport Guns GmbH
Oesterweg 21
59469 Ense-Höingen

Box 4h:
American Tactical Imports
Rochester, NY.

.

.

All for future refrence.

Originally Posted By globalm3: Originally Posted By jackal2001: Adapters will be the same price as our P22 and Mosquito adapters at $45 MSRP. If you send your Form 1 SBR rifle to Gemtech we will cut and recrown your barrel and install the adapter for $150. If you do this can you attach a airsoft silencer if you dont get a stamp for the can?  or is this adapter only for a real can? TIA

The Gemtech Adapter is for a real can.  I have no idea how different faux airsoft cans attach.

Originally Posted By globalm3: Originally Posted By jackal2001: Originally Posted By globalm3: Originally Posted By jackal2001: Adapters will be the same price as our P22 and Mosquito adapters at $45 MSRP. If you send your Form 1 SBR rifle to Gemtech we will cut and recrown your barrel and install the adapter for $150. If you do this can you attach a airsoft silencer if you dont get a stamp for the can?  or is this adapter only for a real can? TIA The Gemtech Adapter is for a real can.  I have no idea how different faux airsoft cans attach. Thanks for the reply. If I get the modification and dont want a can is it still legal or does the adapter itself make it illegal since you can just screw a can on it? tia

The barrel needs to be cut and crowned either from Gemtech or a gunsmith.  Doing so would require to fill out NFA Form1 paperwork to make this a SBR weapon.  Once that is approved you can have the barrel cut and crowned and just leave the adapter on.  At this point it is a SBR and doens't matter if you have the adapter on or not.   You would be paying $200 for the tax stamp for the SBR process.  
If you have further questions IM me or ask in the General Class III section in the Armory.
Thanks

Any chance to get the pics back up?  

I'm formulating an evil plan in my head.

Oh, big thanks for the info jackal2001.  You attention to detail if appreciated.    

They will be back on the 26th of each month.  That is when the account recycles for the month.  I've already moved each section to its own photobucket account, but somehow people still suck up 25GB a month on the pics.

I would suggest saving the whole web page as a .mht file when the pics are back up.

Sorry for the inconvience.

Originally Posted By jackal2001: They will be back on 10/26.  That is when the account recycles for the month.  I've already moved each section to its own photobucket account, but somehow people still suck up 25GB a month on the pics. I would suggest saving the whole web page as a .mht file when the pics are back up. Sorry for the inconvience.

No sweat and thanks for all of your work on this!!

Originally Posted By Ridge_Runner_5: So the SBR barrels...would that be a Form 1 for creating an NFA firearm?

Yes

Can you get the pics hosted here?