Note: The Steipler did not tell him to go to the army. For the Steipler - No Yeshiva bachur should ever go to the army. He asked if he should go to the army through KBY or go to a Charedi Yeshiva and then go to the army not in the framework of Hesder. Meaning - should I go to the army or should I go to the army? So the Steipler answered that he doesn't know him personally so he can't answer. If the question would have been - Should I go to the Yeshiva or to the army? There is only one answer the Steipler would have given. See below for the letter. That being said - Rav Schachter is a very special person.