I've shot T/C rifles for a long time and in just about all cases, the supplied sabots work just fine when using the TMZ bullets. Some barrels may be slightly tighter and that's when shooters may switch over to the TEZ bullet and sabot. The TEZ should load with no problem in your rifle and most likely the TMZ will too. You need some loading force.

What can happen........ if you have a sabot that may be too loose, the bullet and sabot spin at different rates or, the bullet may hardly spin at all. The sabot spins with the rifling, yet the bullet doesn't spin equally with the sabot, and that will certainly create a loss in your groups the further the distance. Bullets must be stabilized, which is what will give you the better groups. If the bullet is losing stabilization, you'll experience exactly what you're mentioning. In some instances, some target shooters will actually knurl bullets, which causes the bullet to grip inside the sabot, giving it stability.

Your TC will shoot BH209 very well with no modifications necessary. Learn about BH209 BEFORE you start shooting it. It has a MAXIMUM CHARGE OF 120GRS VOLUME AND NOT 150 as with other propellants. Most shooters find that 105 to 110grs by volume is the perfect charge in most rifles and manufacturers. http://www.blackhorn209.com/

I have a feeling, that if everything is correct with your rifle and scope, you're shooting it from a sled with proper shooting techniques, its most likely your sabot. Try shooting your bullets with the supplied sabots next round.