The main problem with turning a .50BMG into an airsoft replica. The necessary design element/the advantages we would get in them would simply turned into a hindrance when we apply them to airsoft.
I think Silverback really did a job well done on making the HTI, since I couldn't think of any other .50BMG replica that is more practical than that for war games. Save that magazine.
I would wait until DSR-50 shows up in airsoft, since I think it would be the best .50BMG replica if done correctly on critical areas.