So my 400E has arrived and I have had the chance to shoot it a couple of times now.
I will have to say that I'll have to temper my expectations a bit - it is only a BB gun after all.
I've tried a couple of scopes/red dots on it, but so far the little 4x32 I had in the shed works best. I will have to say that everything I've topped it with has shot low & left (30 feet distance) so I'm wondering whether the top Pic rail is true. Every optic has run out of elevation adjustment and I've had to shim up the rear end.
I do have other full auto BB guns (CO2), and I actually enjoy the sound they make better than the 400E (albeit they do have the issue of decreasing muzzle velocity as the CO2 gets cold during full auto use). And it is nice not to have to worry about constantly changing out CO2 cartridges. But not having any experience with full auto airsoft guns, the sound of the AEG auto action of the 400E is a little obnoxious.
The speed loader which comes with the 400E seems really fiddly to me, even more so than other BB speed loaders I have used. It takes some practice and development of technique, but in the end it starts to work O.K. I still don't think I've ever gotten the magazine full. But both the mag and the speed loader seem to be improving with more use. Everything is real tight when brand new.
Feeding and firing has been flawless in my short use of the gun so far.
The gun seems well built and is definitely heavy - seems even heavier than a real AR15, but I haven't put both onto a scale.
In the end the 400E is a cute novelty, albeit on the pricey side. Would I buy again? I haven't really found any real use for the gun yet. It definitely is a toy as compared to PCP air rifles, but a cool toy. So unless you already have a need/use for a BB gun, I wouldn't buy again. Not that the gun doesn't seem to do all they say it will do, but in the end it is just a BB gun. With the sound of the action which really isn't enjoyable to me. To me a CO2 powered full auto would give me all the full auto BB play time I would need at a lower price. But I can't fault the 400E for that - that is more down to my BB shooting 'needs.'