Cabage,

It is the Sabot not the Bullet. That yellow sabot that comes with the TMZ has a very thick diameter. The TMZ as you mentioned is a boat tail and you will not see good results using a sabot that is made for a flat base round. You could check with both Harvester and MMP to see if the make another sabot for boat tails or you can do what I did and switch to the Spitfire TEZ Flat base, basically same bullet with a flat base. Then you can experiment with a bunch of different sabots to get the right fit. The Blue sabot that comes with the TEZ was actually too loose of a fit in my Accura so it may work fine for you.