Trebuchet Madness

So while i was working on my creative project for Brit Lit, which was a sword, I began thinking about the good old medieval realm. And then what popped into my mind but the good old trebuchet. What I realized though was that many of the things required to make a trebuchet required apply to physics. For instance, the counter weight of the whole thing is made from a bucket containing a bunch of really heavy rocks. By lifting these rocks up, it greatly increases the potential energy of the counterweight. Then, when it is released, the potential energy is turned into kinetic energy as it swings down and swings the other side up. This kinetic energy is then transferred into the sling and the projectile, usually another large rock, and it is sent in an arc towards the enemy castle. This arc obviously follows a beautiful projectile motion arc until it comes crashing into the enemy castle. Now because the rock is more dense and has more momentum than the bricks and mortar holding the castle together, it is more likely to crash into the walls and punch a giant hole in it. Because if you fired a trebuchet at a castle and the thing just ended up bouncing off the wall, you'd be pretty disheartened or just rather silly for putting something that pathetic in your trebuchet.