
This AEG will heap praises from our WWII veterans and those who in  one way or another have used this weapon in its heyday. Attention to  detail is very meticulous.  The quality of material is superb so as the  workmanship. The only gripe I would muster is the paint finish. The  metal is not anodized but just painted. A little bit of scratch and it  peels off. This is very prominent on parts where there is metal to metal  contact and a bit of movement. 
Pitting this historical piece of AEG into the modern field of AEG’s  would be a mismatch for this has a league of its own. This is way behind  in terms of ergonometric, features, upgradeability and that macho look.  This gun was not designed and built on the basis of aesthetics but  practicality at every turn.
The gun is basically constructed out of all metal parts with some CNC  parts on the inside. It is painted in matt black finish. The overall  looks of the gun reflects the necessity to produce a weapon in such a  short process, in mass quantity, less parts and does the job during the  war.
 The front and rear sights are as basic as you can get. Being a  sub-machinegun for Close Quarter Combat, you don’t have to aim  precisely, just point and spray. The only markings on the body is “STEN  MK II” which is located at the upper portion of the magazine pouch
It takes a bit of patience locking the magazine pouch into place to its  horizontal position. This is due to the absence of a guide or stopper  that would prevent the magazine pouch from moving up and down the body  thus missing on the locking holes. Well, you only lock it once before a  game but several times if still setting-up the hop-up. The magazine  supplied is metal with markings “M.P. 41 PATENT SCHMEISSER” on one side  and “M. P. 38U.40” on the other side. This is as per the real one which  can take magazines from such German weapons.
The metal charging handle is just a dummy. You can slide to a locked  position by loosening the handle. The rest of the opening is prone to  ingress of foreign materials into the inside. Care should be taken on  this matter to prevent water and moisture getting into contact with the  electrics inside.
 The hop-up adjustment is where your patience will be tested. You need  to remove the magazine,  disengage and rotate the magazine pouch to  access the tiny hole for the  hop-up adjustment. You will need a small  flat screwdriver to do the job. There is no marker. Clockwise is  positive while less hop-up is the opposite direction. You then lock  again the magazine pouch to its horizontal position to test the result.  You need to repeat the procedure to get your desired setting. But once  it is set, the setting stays firmly.
We are all accustomed to a proper handgrip on our modern AEG’s. This  particular model, however, is very crude in this department. The  ergonometric is non-existent. You hardly recognize it as a grip but it  is. We can’t blame the original designers or VIVA for this. It was  wartime. They needed a gun that was easy to manufacture with the least  materials and components. Aesthetics was not part of the criteria.
 The trigger assembly is very simple with a contact switch to let the  current flow when the trigger is pressed. There is no safety lock or  fire selector. Just pure BB-spewing automatic fire till you run out of  ammo. A single or burst shot is possible with a quick press of the  trigger. A bit of caution: this part is exposed to the elements. There  is no cover beneath it except the shield of the wide trigger guard.  Water and moisture could seep into the contact points and short it

Forget about modern rifles with rubber butts. This one is solid steel  welded to the steel tube stock. This is built to crack a skull when  butted to an enemy’s forehead during the war. It feels hard on your  shoulder even without a recoil effect of the real thing.
VIVA opted to use Version 7 for the gearbox which offers the possibility  of a plethora of upgrade options available on the market. The gears are  metal which shows good quality for the price. Lubrication is sufficient  on areas which required it. The plastic parts are the cylinder head,  piston, spring guide, nozzle and tappet plate. The cylinder is made of  copper. CNC part is the aluminum block to which the metal outer barrel  and the metal receiver are screwed into.
The inner barrel with the hop-up assembly slots into it as well. There  is a minimal space for upgrades on battery power. The included 7.4v Lipo  battery is just sufficient for the space inside the body. The rather  short inner barrel of 205 mm would not give a good grouping on distant  targets. A tighter inner barrel and a more powerful spring upgrade would  help on this matter.
Numerous trial and error on the hop-up setting finally resulted in a  good trajectory. A muzzle velocity of around 287 FPS-291 FPS shows a  high rate of consistency and an effective range of 35-40 M for a  man-size target. The horizontal position of the magazine on the side  seems to look awkward when compared to modern day AEG’s with magazine  sited at the bottom of the receiver.
 Technically speaking, this horizontal magazine positioning produces a  moment (M) that tends to rotate the gun around its horizontal axis when  the gun is held horizontally. This means that the hand that grips the  front handguard will not only react to the axial load exerted by the  weight of the gun but also counter the rotating force exerted by the  magazine about the gun’s body. This may be annoying and may create  discomfort on prolonged usage but that’s the way it is. It could be  forgiven for the real steel of this gun has helped win a war
With its basic and crude construction, this is a lean mean machine.  Weighing at around 2.5 Kg, it is easy to maneuver and light on your load  out. Just keep an eye on your battery