I understand that you can use hevishot if you can use steel shot. So I searched to find out if it is ok to use hevishot in my gun and came up with the following from the Mossberg site:

Can I shoot steel shot through all barrels ? Not all barrels. Barrels with an interchangeable Accu-Choke™ or Accu-Mag™ choke tube system, yes (with proper tubes installed); however, steel shot is not recommended for older "C-Lect Choke®" or fixed-choke barrels.

I have the interchangeable choke tube system, so figure I can use steel and hevishot. BUT then they go on to say:

Slugs, buckshot and steel shot loads are not recommended for use with an Extra Full "Turkey tube" installed, due to the tube's tight constriction. Do not fire any load without a choke tube installed, doing so will damage the internal choke tube threads.

Doesn't this mean that you shouldn't use hevishot in combination with an extra full turkey tube, such as the undertaker, or any of the Briley, TruGlow or other turkey tubes? I am still confused!