/3/ - 3DCG

Beginner here looking for some tips. I've been working on a simple scene in Blender geonodes that I started to think would be a better fit for houdini:
Basically I have two metal pipes (A) which are part of a biomechanical limb, with one pipe nested inside the other, moving up and down like a piston. Then I'll have muscle fibers wrap around the limb (B).
Simple enough, right? So here's my problem: I'm making the larger of the two metal pipes with two cylinders, one (the wider of the two) being the material, and the other being used to cut the middle out via a boolean operation. The boolean operation doesn't work. There is no change to the wider cylinder. I have both cylinders set to mesh mode, endcaps on, and the boolean is set to subtract. I have the boolean node selected for view. Why isn't it cutting?
Sorry for the basic question, I'm very new and may have bitten off more than I can chew for a first project. Any links to relevant tutorials would be nice though.