Specifically what arrow are you shooting. It sounds to me like you are weighing just the weight of the arrow with no tip. Add the tip (point) and your arrows more than likely weigh 442 grains which is more than enough.
To come up with a total arrow weight of 317 grains I don't even know of any shafts that are light enough to only weigh 317 grains with a 125 gr point.
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