Thanks for all the help. I will not be shooting with a rifled choke tube, I will use standard IC tube. So from what I understand:
-No on the sabots.
-Rifled slugs are OK in a smoothbore and may increase accuracy.
-Brenneke or Foster work the best.
Remington advertises a reduced recoil tactical slug, will this cycle in the M2?
I will get several different brands and try them.
Thanks again!!!!