I made a couple fine heavy arrows out of aluminum for my power bow. I took a 20-3/4 inch xx75 2413 superlite shaft an slugged it with 19 inches of 2216 super slam shaft with a 110 gr brass insert in the 2216,weight 725gr. ,Good fit but I can slide it out to turn,tune it if need be as both shafts seam marks are lined up an cock flètch put on the seam.( they have two seam looking marks but ones just the camo finish line ) don,t know if it means anything? seems to work on lots of arrows for me or it just don,t matter? as I shoot all mine to test anyway. fletched with 4 inch off set gateways ,regular inserts in both ends,100g tips,foc around 20 percent that,s about the same as most of my arrows .shot bare shaft out of my vortex off hand at 10yd an they were accurate,inline an a couple inches high. good time to test as it,s windy an I will see how they do at 25 yd. should be a power bow tamer an drive a big cut head thru some deer .