That alignment tool made specifically for Barnes MZ bullets is not like the spin jag. It's name is very misleading actually. It is solely designed to fit the olgive and nose contour of that specific bullet. It does NOT have a bore alignment ring that is 50 caliber specific like the spin jag does. It's simply a fitted end loader for a specific bullet. That in itself MAY allow for better alignment but not as well as a spin jag with a bore fitting ring to keep the jag straight would be.

Barnes Alignment head:

Spin Jag:

Notice the alignment ring on the Spinjag?