Ive had this for a couple of months now. The weapons build quality is amazing to say the least. It does fire an amazing 400 fps as stated at an EXTREMELY high RoF if you have a 9.6v crane battery in it. The reason I give this a 2 out of 5 stars is because its performance on the field is one of the worst I have ever seen. I have been in airsoft for 6 years now and I know my way around gearboxes very well. I know airsoft guns down to the last screw. I also know that CA hop buckings are generally terrible. I replaced mine instantly with a Systema advance bucking. The hop up still does not respond the way it is supposed to. This is the second M15A4 variant I have had with the same issue. The last one I put in a systema hop up chamber and bucking, still with the same results. With this hop up problem you get the range of an AEP and the BB spread of of someone taking a hand full of BB's and throwing them _--- just a tad over exaggerating :).
Built solid as a rock
Huge battery capacity
Generally terrible hop up buckings
Above affects the performance almost to a point of making this weapon unusable
Rating: [2 of 5 Stars!]