I started with a 10" 44 mag barrel and then went to a 15" bull barrel.
I can say, with the 300gr cast bullets I was using, and loading them both to near maximum for my barrels, the 15" barrel seemed to have maybe 15-20% less felt recoil. I can shoot much more without the hand getting tired or sore. the added weight and length of the barrel seemed to help the recoil considerably.
Just from my own experience. However, I don't own any 10" barrels anymore, but they were fun to have.