OK,
I checked with our authorities. It´s less complicated than I thought.
First, for exporting from Germany to another country (outside EU) you need an export permit. For the type of rifle we usually use (hunting rifles) there is no problem, we will have it within 2-3 weeks max.
To import your rifle to the US we need a copy (fax is OK) of a BATF licence. This, I´ve been told is possible to get for particular persons, but you can also use the licence of a gunsmith or dealer you know.

So, if you want to buy in Germany and have it shipped to the US you have to place an order for the rifle with all data of the rifle you want and your address and the BATF licence as well.
The rifle is shipped by air freight, I´m not sure how much that is.
Timeframe depends on availability of rifle in stock. You will get that info when placing or discussing the order.
If you want the rifle to be equipped with optics, no problem, even installed and regulated for the ammo you want. If you also want ammo to be included (might make sense for some specific european calibers*) this can only be shipped by air freight and you might order it together with the rifle and have it shipped all together.

*) better availability of cartridge shells and bullets for the 8mm or the 9,3mm calibers, for example

hope the info is OK for you, if you have questions, let me know.

br Tom