Interesting little tidbit...

In Peterson's Bowhunting, there are two good articles concerning arrows, fletchings, spine, FOC and broadheads.

The author of the one article first points out that you must use the properly spined arrows for your bow. Second, that FOC is drastically ignored within the hunting community. He recommends 8-10% for target shooting and 12-15% for hunting. He actually computes the FOC by balancing the shaft of the arrow (he recommends on a pencil) to find the center of balance. Measure from the where the string sits in the nock to where the aluminum arrow meets the insert (to where the actual head screws in on carbons). Next measure from the same point on the nock to the center balance, as derived by your "pencil test". Divide the shorter center length by the total length, deduct 0.5 and multiply by 100 for FOC % (or in mathematical terms, ACL/AL - 0.5 * 100). Of course this is by memory alone, but I just roughly calculated my FOC, so I think this is the correct equation.

Now what is interesting here, is by Jackson's site calculations my arrows had an FOC of 11.5%. By the author's computations for actual FOC, my calculations indicated 14.3%. I shoot flat out to 30 yards, two pins---1 for 25 and under and 1 for 25-40---with little drop.

Good article, check it out.

I just responded to this ?? because I found a large disparity between the two systems (~3% in actual Vs. site computed FOC) so thought I would pass this along. In essence, if you have merely relied on a site calculation you may be actually shooting a much higher FOC than you think.

S&R