I have been shooting Beman ICS hunter 400 shafts for a while now. These arrows are being shot out of a Legacy. My draw length is 29" and the arrows are 28" . My bow was set on 64 lbs. I had 4 inch feathers and 100 gr. feild points. Put perfect bullet holes through paper with the fletchings on and with a bareshaft.

Here is where the problems started. In order to obtain a little more speed I turned the poundage up to 72 ( the limbs are bottomed out). In order to compensate for the extra draw weight I went to an 80 gr point ( for the spine ). When I started shooting my groups were not that good. I was no longer able to shoot 4" groups at 40 yards. I decided to shoot it through the paper again. With the fletchings I got a slight left tear but I mean very slight. I then shot a bare shaft.........WHEW.... bad left tear. Immediately I thought my spine was too weak so I turned down the poundage which fixed the problem. Now most people would have stopped there and been happy but not me.

I checked the Beman web site to see if I had the correct arrow. The specified arrow for a hard cam, 72 lbs draw weight, and a 28" arrow is a Beman ICS Hunter 400. If this is the case, why the bad left tear? Are these charts not specific enough about the point weight being used? I don' t understand how a carbon arrow can be so underspined when the manufacturer specifies that arrow size.

Any thoughs?
Should I use an ICSH 340?