The FXII 4x is a short tube scope. It will fit your Remington, but it will only fit between the rings with no extra fore/aft adjustment. If that is the right eye relief for you, then you're good to go. If not, then you've got to play with different ring setups.
The 3x Big Bore will give you a lot more fore/aft room to play with, and you can set it where you prefer it.
I do think the eyebox/image/ease of use resides with the 4x for some reason however. It is the easiest scope to get behind.
