The crhistian's 2a4 turret has a lot of problems and innacuracies. I suggest to read my tutorila which offer a lot of changes plus details I have added with no aftermarket. Still I made some mistakes explained in the text. I tried hard to put all inside a tamiya however I dind't have one other that the already built to try so I desisted. If you need some advice I will be happy to help, contact my by facebook or private.