Oh, I know it's going to kick, I just don't buy there is NO recoil while a bullet is moving down the tube. I posted this in my first post.
A 19" barrel minus the 3-1/2" chamber is only 15-1/2" of bore.
After thinking about it the bore would actually be 15" or less, I forgot about the forcing cone.
So now they build a 3-1/2" slug with I'm sure a big increase in recoil so we can shoot over 2000 fps, then we cut the effective bore down to 15" or less. So how can we make the 3-1/2" slug gun kick more, while slowing the bullet down? Oh yea, lets lop 5" off the end of the barrel.