Why are you sighting in at 25? I like a 50yard zero myself. It will be within a couple inches out to 220yards.
Standard AR-15 battle sighting. One click back on the rear sight, zero at 25 is also zero at 300 one click up. 25/300 zero and 50/225 zero are both pretty standard options, really depends how far out you are shooting. Given the range OP went to is limited, 50/225 would have been better.
When I first sighted my Bushmaster XM15E2S to 25/300, I put a full mag of 30 rds into a single hole on the paper the size of a quarter with stock open sights at 25. But that's a full length 20" barrel rifle not a carbine, and from a bench. The front sight distance and sight radius on the M4 style rifles is pretty bad compared to the full size rifle.