4" eye relief should be fine on an ML. It's all I've ever had. I've been knocked a couple of times though, but mostly when in a hurry. I've since added little rubber boots on the eyepiece of my scopes so that I won't get cut -again. I agree with Cayugad that if the relief is too much, then I end up fishing for the occular window.

If possible, have a demo 6" eye relief scope loose mounted on your rifle at a shopso you can see if it will work for you.