panzerfaust warhead / fist - question about shipping to US

[Schelberg]

Hi, I have a panzerfaust warhead, no tube, for sale. I wanted to sell to Europe but a collector from US asked me to sell it to him.
Do you thing there could be problems due customs and security control once the parcel arrives to US ? I'm not used to sell this kind of stuff
Please let me know, I prefer to avoid problems, and so for the buyer.
Any opinion would be appreciated.