SAAMI Grendel Barrel Makers?

[Harpoon1]

New to the forum, playing catch up with Grendel, trying to wrap my head around the variables.

The earlier list shows "Ballistic Advantage" using a SAAMI chamber, but BA says its a "type 2"?

What am I missing?

http://ballisticadvantage.com/18-inch-65...arrel.html