Yes, same thing happened to me too. I posted this back on a KT build thread a few weeks ago. Mine started out as the little black plastic cracking on the part that goes on the end of the barrel to make it recoil, then noticed my rotation ring gear broke, around the screws. I must admit I did put some force on all the screws that hold these plastic parts on. I had to order parts from tamiya america, lickily it was cheep, and pretty quick. You can order these online through their online store. I re-installed these parts and just barely felt for them to get tight without being loose. Since I finished the build about 2 weeks ago, no problems. I purposly look at these parts every time I turn the tank on. Should the plastic be tougher? Sure! Was it my fault? Yep, I guess nothing is perfect.