Clear-cut answer

Q: Hey Harv.. What does more damage? A Boomerang or a Samurai Sword? My stupid coon friend thinks Boomerang whereas I beg to differ.. Ur thoughts?

A: Firstly, let me mention that you have (possibly unwittingly) used an offensive word for an indigenous Australian. The correct word to use is "Māori", for future reference.

As for boomerang vs katana (the name for the classic Samurai sword), are you kidding!? Boomerang has a bit of range, yeah, but all it can deliver is an effective bump to the head. The katana will CUT YOU IN HALF.

Take it to the field and test it with your friends.

The victim of the boomerang will be all... oooh, you hit me with a boomerang and I've got a real googy egg on my head, why did you do that, it really hurts...

The dude on the sharp end of a katana would be more like, well, thank you Mr. Samurai, I can't say anything because I'm DEAD; spurting blood 10 feet across the room and my arm came right off and I'm split in two at my sternum and I can't even tell you this because I died almost immediately.

Boomerang, indeed!