It was my understanding that Grand Jury files are sealed by law.
It's complicated. It is sealed under law but the law provides for release if a court approves for various reasons set forth in the federal rules adopted persuant to the law. But that does not necessarily mean material is released to the public. It usually means that there can be a confidential sharing between other investigative bodies. Not to openly score political points.
Jerry is not willing to even state whether his kabuki dance constitutes an impeachment inquiry yet he wants to obtain the material to see if he can come up with a reason to start an impeachment. Not exactly a legally tidy process.
Anyway, unlike Sessions and Rosenstein and that crew, Barr is smart legally and not lazy or part of the swamp and will either knock it down or appeal it up to the supreme court so that Jerry will not get the info in the timeframe that his political agenda calls for. You know, you only need to add a month to this and the dems are going to be swimming in dirt from Horowitz's report. The republicans have plenty of investigation games they can play and further too if Jerry wants to. And, or especially if, he does not want to. Let the good times roll. Giddy-up. The more investigations the better.