Do those DUmmies realize that Ar-15s are chambered for more than one round? They are made for several different calibers.
That post that "liberal N proud" thought oh-so-clever is so filled with ignorance as to present some difficulty as to where to start.

As was already laughed at by th4 and PGR, "clips",

.

Even a DU-member alluded, very vaguely, to the fact that courts have already seen through back-door schemes to ban firearms by making them extremely difficult or expensive to obtain or use.

And, a bit beyond what you pointed out, "liberal N proud" seems unaware that the AR-15 system uses
multiple calibers of the same ammunition that a bolt-action or single-shot rifle would use.

As for that magical 10-shot
magazine does the "liberal N proud" fool not realize that extra magazines are readily available, and a reasonably skilled shooter could change magazines in a very few seconds?