My bow was doing the same thing, getting great groups w/ boradheads about 2 in low. For me i just figured out that it subtracts bout 5 yrds off my range. So for my 30 yrd pin w/ field tips, its a 25 yrd pin for broad heads. I do this because i use Mechanical heads for long range shots (45+) and they fly like my field tips. Otherwise i'd just adjust my sight.