I've been experimenting with arrows also I made some 100gr brass inserts to fit XX75 2219arrows. I used 100gr target tips, 4"vanes and alum flat nocks With the tip they weigh 570grs. Very heavy arrow!I shot them at 15 ydswith my Profusion. The penetration in the target was incrediable, I also made some 100gr inserts to fit some Easton carbon arrows, The Eastons weighed in at 392 with the insert. I also weighed some Goldtips and they weigh in at 304 with their brass insert. I found no difference in accuracy when shooting the three different arrows. As Awshucks said, DO NOT shot a second arrow at the same spot without removing the first arrow unless you like to ruin arrows. All three arrows will group within a quarter for me . The XX75's hit about 1&1/2 lower than the Easton Carbons. The Goldtips hit about 3/4" higher than the Eastons. As soon as the weather operates I will try them all at 30 and 40yds Can't do it now as there is far too much snow,