I was shooting today and decided to screw on a 100gr Grim Reaper expandable. At 20yds I'm about 6" rt and about 4" high, and the arrow seems to wobble realy bad in flight.I shootleft handed. When using my 100gr field points I'm grouping 5 out of 7 arrows inside a 3 1/2" black dot I painted on my target. The arrows seem to fly ok. Any ideas as to the problem? I haven't papertuned thebow yet.

I think tuning the bow would be the first thing you should try to get done. Im no expert at tuning, but when i have my bow tuned, my Grim Reapers fly right with my field points out to 50 yards. Tune that baby up and not only will your broadhead groups get smaller, but so will your field point groups. Good Luck!

Not enough info. But the inserts in your arrows may not be right.
did you spin your arrows after yu put the broadheads on. Are your arrows porporsing or swaying side to side. Could be fletching problem. definetly need more info. Good Luck Mike