Scarebird caliper install

Hey guys, question about the celebrity caliper install on Scarebird style brackets. I understand that the calipers are single piston and therefore need to slide, but if I torque the caliper bolts to spec on the brackets I don't understand how I will get any movement. The metal sleeve that the bolt runs through on the caliper has about 1/4" length extra sticking out on the pad side, is that what slides? It's pretty tight and I can't move it by hand? Any info is appreciated