They are faster because they are lighter. They improve arrow balance giving you less tail weight. The disadvantages would include not being able to control big fixed blade heads. I have shot a 4blade Muzzy with 2" blazers and had excellent results. But, that head is on the small side imop.
Another disadvantage could be that the shorter vanes, such as blazers, are slightly taller and they are stiffer, so if you have any contact issues, they will only make it worse!
I love my arrows with the blazers, even with my fixed inner-locs, they fly like darts!!
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short vanes
