The mag is behind the trigger, but the sear and hammer are behind the mag. There is a cubersome transfer bar arrangement in a MAC semi. You could easily enough make a traditional mag in front of the trigger gun. While they are not as cheap as they used to be, they do turn up on gunbroker, and things like firing pins and recoil springs would be easy to get. Another advantage would be that the telescoping bolt design would put the bolt over the mag well when closed with a few inches of the barrel inside the receiver. That would mean you would have less barrel sticking out front, so a legal 16" rifle would look shorter. Food for thought.
I have a Cobray M11-9 bolt and recoil assembly. Maybe I should try a mock up.
I like the CZ 7.62x25 idea.