I am thinking about buying a blunt sword in the US and bringing it to Germany. Does anyone have any experience doing this?

Good afternoon.

General of the United States is very lackadaisical in regards to weaponry like swords
In fact, I’d be surprised if they cared if you brought a gun home as long as you had paperwork with it

Just put it in your suitcase or in its own suitcase and you’ll have no issues

You would get in more trouble bringing a kinder egg home, then a sword :-) seriously Google it

The usual advice is to pack it in checked baggage, preferably with a hard case, labelled SPORTS EQUIPMENT with a card with your name and cell phone number inside. It is also a good idea to have a paper copy of the receipts with you for the Steueramt.

Put it in checked baggage and the airline doesn't care in the slightest, at least depending on size. One of the advantages of the Sports Equipment idea is that it's often exempt from size restrictions.

For import, look at the value and whether you need to pay tax, and look at the laws on owning that object in your destination country. For most of Europe blunt swords are totally fine.