Further, the round, while smaller, is launched at much higher speed, and appears to be a "hybrid" round.
In some science fiction, a Hybrid Round is a physical weapons round that is charged with energy, surrounded by plasma, or the like. It's a directed energy weapon, as well as a physical weapon, thus Hybrid.
Since it's known to be a physical round, but it has the blue trail, even in space, I believe it to be a hybrid round.
This would further explain its effectiveness, despite smaller size, since it would have more penetrative capability, being surrouned by superheated plasma.