[darkgael]

I'm of the other school of thought about the .416 Rigby as it would be as an Encore. Yes, it's ported. I was not impressed with recoil reduction for the 500 S&W in the 15" pistol barrel. So I wouldn't expect much in this case. I haven't used the flex tech stock; that might be a help.
The fact is, ported or not, you are firing a very powerful cartridge out of a rifle that weighs less than seven pounds. Even with a scope, it's less than eight.
My Ruger #1 in .416 weighs 9.5 with its scope and it's a heavy kicker. I don't see that porting making up much of the difference.
I also have an unported .300 Win mag barrel for the Encore. Recoil on that is nothing special.
Pete