Hmm, I'm in the market for new arrows and I was going to order this week. I heard heavier aluminum arrows would be best. I was looking at the XX75's. I currently have 2117's 400gr but Im being told 2117 is too heavy and I could be more accurate with a little lighter. 45lb bow 30" arrows, what size would you recommend? I never heard of those brass weights until i saw them the other day in a magazine. You said insert them to my FOC, what is FOC? Thanks for the help, Happy 4th!