From what I understand, the defense of Hillary that she did not violate 18 USC 793f hinges on whether her private server is a "proper place of custody". If she can argue that her server was a proper place of custody, then she did not break that law.
However, the rest of the statute reads: "(1) through gross negligence permits the same to be removed from its proper place of custody or delivered to anyone in violation of his trust, or to be lost, stolen, abstracted, or destroyed, or (2) having knowledge that the same has been illegally removed from its proper place of custody or delivered to anyone in violation of its trust, or lost, or stolen, abstracted, or destroyed, and fails to make prompt report of such loss, theft, abstraction, or destruction to his superior officer"
If the first part of the clause "permits the same to be removed from its proper place of custody or delivered to anyone in violation of his trust" has not been violated, the second (bolded) part will have been if the Russians indeed have them. Since this is an "or", I read it as "through gross negligence permits the same to be lost, stolen abstracted, or destroyed". They have definitely been stolen, so Hillary definitely broke the law. But I'm not a lawyer fully versed on the meaning of "or".
I will love it if, at some point, Hillary's defenders have to argue "it depends on what the meaning of or is." That would be a lovely twist.