I just bought and test fired this little beauty, a GSG-5. 24+1 rounds of 22LR in a dead ringer copy of the H&K MP-5. It is a very high-quality German-made trainer/plinker rifle. It has a legal length barrel masked by a fake suppressor shroud, 4 rotating peep windage adjustable sights, claw mount compatible, single high capacity magazine, same cocking lever and safety as an MP-5.
This little gem is not a toy and has a serious heft like the real thing. It points perfectly and the cheek rest is perfect for me (some other brands don't let me get low enough for the rear sight. The trigger is good and the gun drills one hole 24rd groups at 10 yards semi rapid fire with no effort on my part. I am sure it will shoot accurately at 25 yards slow fire too, but rapid fire is what makes this gun so kick arse.
I fired 200 rounds of CCI Mini-Mag high velocity (1235 fps) and 50 rounds of CCI Velocitor hypervelocity (1435 fps) with zero stoppages or jams. The bolt holds open after the last shot (a feature that worked everytime). There is a little plastic piece that inserts into the chamber that was discarded by the gunsmith who prepared my gun. In most guns this piece is not needed and discarded. The GSG-5 uses this piece to decock (dry fire) the gun before disassembly. In lieu of this missing piece, I use an aluminum dummy round to decock (dry fire) prior to disassembly. The gun has a magazine safety and the bolt will not close on an empty mag. This is actually a good feature as dry firing without a dummy round can damage some 22 rimfire guns.
Disassembly is a bit fiddly as tools are needed (included) and the screw fasteners appear delicate. The polymer rear stock attaches to the polymer trigger assembly with only one pin/screw and the hole in the trigger assembly was a tad oversized, making the stock wobble a bit. I applied one layer of aluminum tape (the good type of duct tape) to the pin, and now the stock is much steadier. The rear sight has a windage set screw and adjustment screw, make sure both are tight before shooting (my adjustment screw was very loose). It thought that the screw on barrel shroud/fake suppressor would loosen with shooting, but it stayed tight without any Loc-tite. Someone reported that the mag follower small nut and bolt loosened, but mine was very tight.
Magazines are in very short supply. My single mag will hold 24 rounds. I could sure use a couple more of these mags. Even a few short 10 rounders would be nice. But owners are apparently hoarding mags, making them hard to come by. One owner said not to grasp the mag when firing as it can induce malfunctions, but I find holding the fore grip simple enough and did not feel any need to hold the gun by the mag. The mag has integral mag spring depressers on each side, making loading mags easy on the thumbs. Because of the high capacity, my GSG-5 was classified as an assault weapon, and I had to go home to get proof of citizenship (voter ID, passport, or birth certificate). Luckily, the salesman held the gun for me, as many other customers and a few salesmen were clamoring to buy it ($499).
The mag release and manual safety are fully ambidextrous. The cocking lever works best for a righty, but it is easy to reach over if you are a lefty. Sling mounts are on the left side, optimal for a righty. The gun was fairly easy to fieldstrip (with the supplied tools) and clean, however, do it at home as the small fasteners could get lost in the field. The bolt assembly does not look user friendly for detail stripping.
There are some MP-5 and air soft accessories that may fit this gun. Some users have gone all out with optics, collapsing rear stocks, vertical fore grips, lasers, etc. I think I will keep mine simple as is. It looks gorgeous in the photo (stolen) as stock does it not?