I was wondering if a to stiff arrow spine will cause poor grouping? I wanna say yes but I wanna ask the guru's of BH.com. I have a Bear Legion 64# draw, 28 in draw length and 29 in arrows, 100 gr slick tricks and 340 Beman Ics hunters. I switched to 125gr and it "appears" I'm getting a little better grouping. My broadheads was hitting left with 100gr. 125's appear to be a lot better. I think I'm headed in the right direction with more weight at the tip is making it just weak enough to fly great.
I don't think the spine had as much to do with the better grouping as the increased foc. 100 gr on front of a 29" arrow is a little low.
I didn't even think of foc affecting it like that. I was just measuring that for the 100gr the other day too (10.34%). I'm gonna have to go back and do it for 125gr now. I have this screen name for all my forums.