shakes head..... When you boys just listen and be quiet?
ONE SIZE FITS ALLThor.
Its not the original bullet where you needed the sizing sample before ordering.
The one size fits all thor is .503-504 diameter and shrinks down to the proper size as you start it into the bore.
Original thor one the left.. One size fits all on the right
And no, the slits do not harm the FPS any. 1,801 FPS tested in a 24" cva wolf & 100 grains Blackhorn209 with the 300gr one size fits all thor.
You are welcome.