NYC Airsoft

In the picture below, the top Hop Up Chamber is the one from the H&K. Bottom left is a G&G version and on the bottom right is a SRC brand. As you can see by Red arrows, the cut out for the top of the hop up chamber is similar in design to the ICS version shown in the second picture, but I am not sure it will work. I tried the SRC version and even tried grinding down a spot and still no go.

Contacting Umerax USA was a waste of time and no response back from Evike when I asked about other MP5 Chambers that might work. Any help Appreciated on this.

That's weird. That ledge is throwing me for a loop as well.

Short of the 'locking lugs' on the round portion [below the arrows and closer to the camera], you could try an m4 hop up and see if it fits [presuming you have an m4 replica lying around to borrow]

That was my next step as a few of them looked like they would work. Biggest update is that after a slightly abusive letter to UmeraxUsa, I got some action on the Hop Up Chamber. they are trying to find me a replacement so that i can get the gun working.

In the mean time, I will try and M4 Hop up Chamber and see how it works out.