Gun-controllists complain that “assault weapons” (i.e., rifles that look scary) have no legitimate self-defense purpose, but that complaint is being undermined by the Department of Homeland Security, which says select-fire weapons can be “suitable for personal defense”.
In a recent solicitation, the DHS is looking to buy “5.56x45mm NATO, select-fire firearm[s] suitable for personal defense”. Basically, this refers to either the M-16 or M-4. In particular, select-fire means that the weapon can be switched from semi-automatic to fully automatic.
So the DHS is saying that fully automatic weapons (in particular the M-16 and M-4) are suitable for personal defense. The AR-15 is the same gun, except it does not support select fire, and is semi-automatic only. So while the controllists claim (falsely) there is no self-defense use for the AR-15, DHS is saying that a strictly more effective weapon is suitable for self-defense.