I'm trying to gain access to the Castle Armory, but I'm stuck at the point where I need to clear the rubble from the tunnel leading to the armory.
Ronnie Shaw suggested I use explosives, I tried throwing a few grenades at the tunnel, but that didn't work. Firing a nuke in that small room also doesn't look like a good idea. The quest marker is on the Workbench, so I guess I'm supposed to craft explosives somehow.
How exactly do I clear the rubble there?