Germans are unfortunately no longer allowed to inherit a gun. They first need to have passed a very extensive test about laws and firearms. Furthermore, they need to prove that they have a legal need, being a member in a gun club for over one year, being a licensed collector, or having a hunters license.
The licensing fees are different within Germany but generally range from €12 to 20, to register a gun and again to have it taken out of the papers. The initial permit to purchase can range from €20 to over €200. A firearms dealer license costs closer to $2,000 and is only issued after a hard test in front of a committee at the chamber of commerce.
Since property is protected and cannot just be seized, the gun would need to be deactivated to be kept. Flobert rifles and single shot rimfire rifles therefore are available in abundance and rarely sell for more than $20
Obama would love to check into it!