I tried the fits all Thor and had to pound them in. If your bore is .500 and the Thor is .503 it's not hard to figure out how they're going to load. Those slits don't work as good as you think.
It's better to get the sizing kit and get the right size bullet for your bore. I can load those with my thumb.
The fits all bullets are a good idea, but if you have a tight bore you won't like them.
That was my experience with the fits all bullets. I sent them back.
I find it easier to hunt the rifle seasons. I can use Barnes sabots for rifle seasons.