Madbull Licensed Full Metal LANTAC Ver. 2 Receiver for M4/M16 Airsoft AEGs
(Color: Black)

"Madbull full metal Lantac V2 receiver m4/m16
I originally got this for a custom build from scratch but it doesn't come with all the little parts required, so before having to buy more stuff just to get started I tried swapping in the gearbox from my favorite back-up rifle, a Classic Army delta.
This rifle has proven to be quite reliable but it felt very flimsy and the dust cover would pop open all the time due to body flex.
So, obviously there were some modifications and alterations that had to be done but other than sizing and fitting a few things it was all quite an easy swap. The buffer tube nub doesn't have a groove for wires but neither did the CA delta. Almost everything was a perfect fit, with some modification. The only part that required a grinder was the bolt release lever, and only because the upper has to slide on and wouldn't pass.
My back-up rifle is now solid as a rock and looks bad-@$$ with the two tone black metal and tan plastics, so I threw some upgrade parts in the gearbox and a black python in with the included hop-up and it's got some sting now.

The hop-up included is okay but it seems to have a beveled bucking port, it took a lot of work to get the bucking to push all the way in far enough to get the barrel clip on, but in this new body it is out performing the CA factory rotary hop-up which was spot on in the original rifle and still quite accurate.

This receiver set is tight, snaps together and requires some persuasion to press the pins in/out. The front pin has a retainer to prevent it from getting lost, like G&G front pins, so don't push it too far out.

The mag well is pretty small but matching magazines to guns seems to be a common problem in airsoft.
It did add a little weight to my rifle but minor compared to the solid feel and lack of dust cover popping open as before.
I like it, I'm so glad it fits and works perfectly with something I already had that needed it.
It comes with some bits and pieces for finishing but several pieces are not included, that's the only reason for the 4/5

"This is a pretty good receiver. It feels solid, and I haven't had any issues with paint scratching or anything after having it about a month. There however a few problems with it. My ares amoeba gearbox fit in it but it doesn't allow me to go all the way on to "Safe". It lets me go halfway into it so the safety does engage so it's not a huge problem. I've also had trouble finding mid-caps that fit it. I've tried G&P, VFC, and Hexmag. The G&P and VFC mags both fit and feed fine but in order to get them in, I basically have to slam them in. Getting them out is also a challenge. The Hexmag doesn't fit in at all. I tried jamming it in and I had to have my buddy hold the gun while I pulled the mag in order to get it out. For whatever reason though, I haven't had a single issue with hi-caps. So if you only use hi-caps then this won't be an issue for you. I, however, prefer mid-caps so this is a huge problem. Another problem I had was trying to get a buffer tube on. I had to hammer it on. I tried two different ones, both were a challenge. Once it's on, you're not getting it off. I also couldn't use the quick spring change feature of my gearbox. It simply didn't line up correctly. Besides that, it's a great receiver.
The hop-up it comes with is fantastic. It's almost as good as the ProWin hop-up I have in my other M4. It fits perfectly into the receiver and has the nice feature to add madbulls tracer unit to it which I am probably going to do. The bucking and spacer it comes with weren't the best so I swapped those out.
All in all this receiver is worth the money if you're okay with those small issues. I would recommend saving a little more and getting a slightly nicer receiver.