The DD-Rifle is an amazing weapon based on the (highly) successful DD-Ray created specifically for use by the (semi) powerful Ducky Empire. It was probably invented sometime around the 1st Ducky War, as it is one of the primary weapons of the Ducky Empire.
Another notable feature is the fact that it can shoot people... and kill them! I know! It's weird huh? I bet you've never seen a rifle like that before! Most rifles can actually do this, but Ducky likes to pretend he is more awesome than everyone else, even if he isn't.
The DD-Rifle is actually an efficient firearm when used properly. However, most of the Ducky Empire's soldiers don't have the training you'd find in a rock, and they don't have the slightest idea how to use this weapon. This is the main reason is has not caught on in other parts of the UnWorld.