The guy at Bass Pro Shop you spoke too is stupid !!!! Blazer vanes are great, been using them for like 5 or 6 years. I was shooting 4" vanes, and all was good, tried Blazers on a few arrows, and I picked up a little speed (not much) but I was shooting flatter and tighter groups. The Blazers are on the Carbon Express Maxima 250, shooting both Mathews Switchback XT and Z7