"If you are looking for a decent WWII replica at a reasonable price, the AGM MP40 is a great choice. If you are looking for a first gun, you may want to look further. Why? Read on.
As a replica goes, it is pretty close to the real thing, with the biggest inaccuracy being the fire selector switch. Although not historically accurate, the semi-auto capability is a nice feature.
The body is full metal, with the exception of the two side receiver panels and the removable pistol grips which are durable plastic.
The AGM MP40 runs a modified V3 gearbox. The GB shell is not very strong and specific to this gun only, so I do not recommend installing any spring larger than an M120 equivalent.
FPS is fairly low, right in the 300-330 range. Range is also nothing grand, about 100-125ft. Rate-of-fire; I've have heard the ROF was low, but running a basic 8.4v battery it seems decent to me - probably in the 750-800rpm range.
The battery is stored behind the gearbox and space is limited. I was able to fit a 9.6v mini-type in by turning it so the wires were facing the rear of the gun, but it was extremely tight.
The upper receiver splits into two sections allowing access to the battery compartment, and even when locked together, there is significant wobble between the receivers. The stock is also quite wobbly when unfolded, although once you have it shouldered it isn't so bad. Another con is mag capacity. 40 rounds just isn't going to last more than a few seconds. King Arms does make 110 round midcaps, but they are plastic and hard to find.
For a WWII enthusiast or a heavy CQB player this gun should suit you fine, but due to the low FPS, range and mag capacity, you will find yourself severely outgunned by most other guns out there."