Ratio of arrow weight to bow draw weight

[ronbow]

Anybody got an update on the recommended arrow weight\draw weight. I have always heard that it was 6 grains arrow weight to 1 lb. draw weight. Thus a 70 lb. bow should bbe shooting at least a 420 gr. arrow. Does this still to the new single cam bows? I shoot a PSE Thunderbolt Lightening one cam with about  400 gr. 2213 alum. arrow and would like to try a lighter carbon arrow. Am I asking for trouble ? You always IBO speeds as 300+ fps so they gotta be shooting straws or something.

[willis5]

IBO speed is is 70lbs. 30"draw 350grn. arrow weight. That is 5grns per pound. Yeah that is light. The reason manufactures show you the IBO is to compare their bows "potential" speed to others with the IBO standard.

Will you be shooting arrows that are only 5gr per lbs for hunting? I hope not. The arrow will shoot fast and flat, but it may not have the energy to penetrate enough for a clean kill. For 3D shooting I would shoot a fast bow with a light arrow because I want flat trajectory when judging distance. I dont' need the penetration of a hunting arrow.

I am unaware of any "standard minimum" grain per pound, but the lighter you go, the closer you get to dryfiring your bow... that can't be good. 6 grains of total arrow weight per pound is pretty light for hunting IMO.

[jdbe]

5-12 gn/# depending on your bow and preferences.  A good rule of thumb for hunting with a fast compound might be around 7.  If you were going after pronghorn, then a little less.  For traditional, you would want 9-12grn/#

[Myk]

For whitetail and typical hunting weight bows I would think 5gr/lb would be enough to penetrate unless you have a problem with shooting heavy bone. Grains per pound is not telling you what the kinetic energy or the inertia is. 5gr/lb out of a 80lb bow would be more energy than 5gr/lb out of a 40lb. Longer/heavier arrows will have more inertia than shorter/lighter arrows. Then you're not taking arrow drop and range estimation into the equation, high gr/lb won't do you any good if you're a few yards off on estimation. There is no one thing on a bow you can use as a deciding factor for its huntability.

The reason people don't hunt with 5gr/lb is that bows tend to get very noisy when shooting that light of an arrow. I stopped going lighter at 6.5gr/lb because of noise. I've since lowered my draw weight and am at 7.5gr/lb and the bow is very quiet. If my bow wouldn't have been so noisy I would've went all the way to 5gr/lb, the faster it went the deeper it penetrated into my target.

I may be outdated but I've always heard that 5gr/lb is the minimum. I know I've had bows that stated their warranty was void if anything lighter was shot. My present not so old Martin single cam manual states that. So the answer to the original question is, Yes, you are probably asking for trouble. You should consult with PSE and/or your bow manual.