Broadheads are such a pain. Make sure that you allign your broadhead with the fletching (assuming you are using a fixed blade/replaceable blade). Spin test the heads. A broadhead will act as a rudder just like the fletching. If everything isn't in line you will have problems. The compact broadheads of today shoot much more accurately then the ones of yesteryear. Also, your arrow rest could be the problem. Going back to the rudder thing, a field point will have less resistance coming off of a fixed rest. A broadhead will stear the arrow more and will magnify any imperfections that the arrow may encounter coming off the fixed rest.