The G36 is a 5.56x45mm NATO assault rifle designed in the early 1990s by Heckler & Koch (H&K) in Germany for the German Military as a replacement for the 7.62mm NATO G3 rifle. It was accepted into service with the Bundeswehr in 1997, replacing the G3. The G36 is gas-operated and feeds from a 30-round detachable box magazine or 100-round C-Mag drum magazine. Its combination of polymer build and highly ergonomic design yet Spartan simplistic robustness to its style have made it a popular choice with move makers when looking for something very contemporary military to equip mercenaries or cutting edge soldiers.
The WE G39 is a replica of the G36C (commando) variant with the shortest barrel of the G36 family and a flat top accessory rail (with iron sights) that sits lower then the carry handle / sight on the full size G36. The G39 feeds from a 30 round magazine but its large gas reservoir means it can easily empty a whole magazine rapidly with virtually no cool down issues. Clocking in pretty dead consistent at 350 fps, it is powerful enough to engage out to short-middle range but still low enough for very short and indoor use making it flexible for urban fighting sites like a commando length short barreled rifle should be.