I've done a bit of hunting over the years with most popular calibers. The .303, whether it is a no 1 or a no.4 is an excellent deer and/or moose rifle. I know there are many out there who think it is too light, but not so. The contraversy will rage indefinately, but the proof is in the shooting.
As for the sighting in process when using the 200 yd battle sight, set up on a known 100 yd range and using the rifle's 200 yd battle range sight configuration fire one round off target to warm the barrel. Then fire 3 rds using the same consistant target point of aim to confirm your firearms MPI (main point of impact). Once zero'd and If you've done it right, the grouping should be about a 1/2 to an inch above the aiming point you selected at 100 yards. One of the observations prior is dead on, all you need to do then is beware when you engage your target to remember the point of aim, but in the case of the deer you will do just fine as long as buck fever doesn't do you in.
A lot of hunters actually site in at 100 yards and select the MPI about an inch above anyway.