sorry about the delay, had some issues come up.
The hop up chamber/assembly on the JG G36c. The mag feed port as can be seen here protrudes roughly 1/4"-1/2"

After comparing the Battleaxe m4 conversion magwell, I noticed that it came pre molded with a feed port of almost identical dimension. Talk about trying to put to male parts together, doesnt work. (unfortunatly I did not take a picture of the Battleaxe magwell before I started chopping)
Side by side view of the JG G36 magwell on the left, and the Battleaxe magwell (right) after I finished with the file.

Top shot of the magwells, I ended up grabing a drill bit and boring out the rest of the Battleaxe magwell to match the JG's.

After about 45 minutes, it works perfectly, and I didnt have to scream and yell at airsoft megastore, or return it.
When in doubt, empty the mag.