My arrows are typically9 grains per pound of draw weight. That formula is one I use for myself and my girlfriend. Her bow is 40 pounds at her draw weight. She is shooting a360 grain arrow, more important than grain weight is FOC, forward of center balancing point, compound shooters can get away with it not being right in the ball park, we cannot.

My bows run from 61 to 70 pounds, my arrows are on average 540 grains, when tuned properly gives super efficiency. Remember that longbows and recurves that don't have as much center shot may require an arrow that is not spined as stiff. Don't think that arrows spined lighter have to equate to lighter physical weight. This is where oldtimers like the 2016, 2018, 2020, and 2117 are worth their weight in gold.

I always bare shaft test my arrows too! One very wise traditional bowhunter(right hander)says she tunes her bows using bare shaft testing. She says she shoots them in until they hit just to theleft of the spot. She states that when she puts feathers on the shafts, it stiffens them and they hit right in the middle. I find no fault with her theory....