You are correct the rifling is not very deep, but I did recover 3 wads and they all showed evidence of engaging the rifling.
I was unable to recover any of the Federal Sabots.
The trajectory info on the Remmy boxes show two very different stories, I suspect that it is all about velocity.
I will just have to breakdown and shoot a few over the chrony.
I may try the managed recoil Remmy's ( 1200 Fps ) vs the "Magnum" loads ( 1450 Fps )
The problem is they are so damn expensive, $18 for 5 slugs thats almost as expensive as my 450NE and 470NE. I wish I could just Hunt with my DR.

Thanks for the input so far.

Regards
Nitro450exp