User blog comment:JakePT/Mass Effect 3 Revealed at Videogame Awards/@comment-1800566-20101212120906/@comment-217683-20101212203410

Crazy thing about firearms. During the service life of the weapon, new versions often come out. One of the things that often happens is that new versions have more (or less) firing modes, in response to requests (or demands) made by users of the weapons. For example: the original M-16 assault rifle was capable of firing in full-auto mode. Newer model M-16s cannot. They can only fire on semi-auto or 3-round burst-fire modes. This is probably what happened here. Someone asked for an Incisor that could fire single rounds for use against unshielded targets.