i have an ar15 spr with a 16" barrel in .223/5.56 that i am building. i am driving myself crazy deciding on an optic zoom range for this rifle. i have decided for sure i want the vortex pst ffp. and i have narrowed it down to the 2.5-10x32 or the 4-16x50 ffp models. i can get the 4-16 now. i am on a waiting list for the 2.5-10 (i dont mind waiting). this gun will be used for bench shooting and varmints from 0 yards to as far as my gun will let me shoot. just a do everything rifle. please give me some insight. i am going bat shit crazy trying to decide what zoom range is appropriate.