I'm going to see if I can make some "foreshafts" with a bunch of different broadheads (not actual hunting heads, probabaly some weaker glavanized for time/materials sake) and difefretn ferules. Try them all off one arrow for the same flight pattern. I think some pine pitch and trhead tied on at an angle, like I do for hand drill bits. Shooting from a couple different weight bows.
I'm thinking of these dimensions so far: A) 1" long by 1" wide, B) 2" long by 1" wide, C) 3" long by 1" wide, and three of each, with the "ferrule" (tapered shaft) behid the point, at the middle, and almost to the tip. Giving me nine groups. I'll do the test this weekend, making the points during the week. I'll have to find a suitable arrow (or make it) and the foreshafts.
I don't know what to shoot them into though- maybe styrofoam? Would cardboard work? I dunno- any ideas?
In theory, the longest point, with the ferrule all the way to the tip should work the best, with the worst being the short blade with the ferrule behidn the point- but we'll have to see