Go to the hardware store and get some little lock washers just a little bigger than the diameter of teh screw-in portion of the broadheads. Take these to the drug store and ask to have them weighed on a grain scale. They should be close to 5 grains.
I did this several years ago to get 125 field points to weight the same as my 130 grain Muzzys.
Good Luck
Greg
"Getting close to the game is the joy of Bowhunting for me, the harvest is a bonus."

Live 15 ft Python after eating a small Antelope!