The Cuomo (30 round AR-15 magazine) is said to have operated for 342 rounds, two thirds of them full auto. This is a complete redesign over the last prototype.
The design is not available at the site that Defense Distributed has set up for "The Island of Misfit Objects" or DEFCAD .
The design is expected to be made available to the public in a few days.
As reported earlier, the group is also working on a 40 round magazine for firearms that use AK type magazines.