I received the long awaited Top MP40 from redwolf today. and here are a few quick first impressions;
The good}; It looks fantastic, is very very solid, and feels great in your hands. The lower receiver and pistol grips are plastic (as on the real gun) and have just the right brown tint and swirls to make them look like the bakelite used on early MP 40's. The rest of the gun is all metal and very nicely made. The way that it comes apart is very clean and installing the 1500mah Nicad is easy, it has a safety switch on the bottom of the pistol grip (not realistic but a nice feature) and the bolt handle pulls back to reveal a dial for hop up adjustment that is very precise.
contrary to what I have read about this gun before its release it does still use the bellows system of gearbox like other top aeg's. These have a tendency to rupture (especially if the barrel jams) and are not very well liked, a piston and cylinder would have been much preferable.
And the Ugly}:
Keep in mind this is based on a very short testing period and so far I haven't had a chance to tinker with it yet but,, It shoots terrible!!!
It chronos consistently around 160 fps and I think I could throw BB's farther than it is shooting. There may be a problem somewhere, I had read that they chrono at 330 fps (although WGC shows 190 fps)
After a little tinkering I found the problem causing the low velocity. At the front of the Top gearbox there is a metal plate that moves in and out as the gun fires (unlike a marui gearbox where the entire nozzle moves) When the plate is all the way forward it shuts off the supply of BB's from the magazine and seals off the barrel ready to fire. That plate was not moving forward far enough and not sealing the barrel and much of the air leaked out the back of the barrel.
All I did was bend the plate forward slightly and now it chronos at 260 fps with .20 ammo( about the same as a stock marui on my chrono).
Below is a picture of the Top Mp40 (above) and the custom MP40 I made a while back (based on Marushin cap gun and AK gearbox) Both are remarkably similar. Both have a similar rate of fire, same battery capacity, The Top is nearly 1lb heavier at 7lbs 10 ounces, My custom has a performance edge at 340 fps.