0 offset will move the centre of the rim out further by 25mm... On top of that, the stock Outdoorsman rim 17" rim is 7" wide... Therefore you will end up with an inch on either side of the centre as well. So, all in all (and Brandon can correct me if I am wrong) you will move the outside of your rim out by 50mm (1 inch = 25mm + the 25mm from the 0 offset).
Going from stock 265 t0 315s is a difference of 50mm or 2 inches. You are already gaining 25mm by the offset of the rim... So you are going to have the tire 25mm further back into the wheel well. When the guys put my wheels on, they told me at full turn I still had more than an inch of space between the tire and anything it would rub on.
I don't know if any of this helped... But I think you'd be OK, especially if you do a level (I have not... I'm stock.)