Not very scientific penetration test.

[Rank Bull]

I was shooting today at a new layered foam target and I figured i would try and see just how much difference poundage makes.  

So the arrow weighs about 600 grains and has pretty high foc and fly well out of both bows.

I shot the same arrows out of a 51#and 63# longbows. Each time the 63# bow would out penetrate the lighter bow by about .5 inches.  Not very much difference when you consider both arrows would penetrate over 14 inches into the target.

Anyway I thought it was kind of interesting. Has anyone had the same experience?

[Zradix]

shoot them through a chrono.
that might help you to understand.

[S.C. Hunter]

The lighter bow was more efficient because it was moving a greater weight in proportion to speed . The 51# bow was shooting 11.76 grains per pound and the 63# bow was shooting 9.52 grains per pound. I read in a article a few months ago that bow speed has to increase by a large percentage to make a difference when using a similiar weight arrow. The heavier bow would need a arrow weighing 740 grains to be as efficient as the lighter bow. The 740 grain arrow would give you 11.75 grains per pound. That's your difference. The best way to view this is a faster arrow without the mass will lose energy faster than a heavy slower moving arrow. You take a football sled have your running back at 200 lbs hit it with his 4.4 40 speed and your defensive lineman weighing 290 lbs with his 5.3 40 speed and see who moves that sled more.  

Could be the arrow was straighter coming out of the lighter bow.

[Rank Bull]

Originally posted by S.C. Hunter:
The lighter bow was more efficient because it was moving a greater weight in proportion to speed . The 51# bow was shooting 11.76 grains per pound and the 63# bow was shooting 9.52 grains per pound. I read in a article a few months ago that bow speed has to increase by a large percentage to make a difference when using a similiar weight arrow. The heavier bow would need a arrow weighing 740 grains to be as efficient as the lighter bow. The 740 grain arrow would give you 11.75 grains per pound. That's your difference. The best way to view this is a faster arrow without the mass will lose energy faster than a heavy slower moving arrow. You take a football sled have your running back at 200 lbs hit it with his 4.4 40 speed and your defensive lineman weighing 290 lbs with his 5.3 40 speed and see who moves that sled more.      

That actually makes sense. I'll have to compare the heavier arrows that I made up for the heavier bow to these arrows.