Bow efficiency

[enewman]

Still playing with arrow weight. First I like using a app that uses the standard 1 ft gain/loss for every 3 gn add/subtract. These calculators are good for reverence only. I'm using a mr5 at measured 26.5 draw at 67 lbs.

Using a 318 gn arrow it shot 324 fps using this number as a reverence with 10 gn on string it gives me a ibo of 358 not changing the ibo number on the app I replaced the 318 gn with these weights and this is what the fps would come out to
429 gn=287 (288)
483 gn=269 (271)
554 gn=245 (254)
603 gn=229 (246)
694 gn=199 (231)
The numbers in () are the chronograph numbers. But as you can see at least with this bow it picks up good at that 500 mark. Big jump above 600. I know everything is speed but a 700 gn arrow is looking good. Has not been that long ago I just got 235 with a 425 gn arrow and I killed a lot of deer at that speed

I think I'll take that 700 gn arrow and go kill a Mack truck

[Bill]

Looking at the top and bottom data, it takes adding 4.6 grains/ to achieve 1 fps loss
Top 3 (light arrow) it takes 3.7 grains added / to achieve 1 fps loss
Bottom 3 (heavy arrow) it takes 6.0 grains added / to acheive 1 fps loss

What it says is the bow's is less sensitive to arrow speed changes with heavier arrows.

I think. Archery physics.

[Mudslinger]

Awesome. That shows that the bow efficiency goes up with the heavier arrow. A heavier arrow will absorb more of the bows energy rather than going into noise and vibration. If you woud do some figuring on your KE and moemntum and see where that stands. The only draw back to your figures is your draw length, but those are still some impressive #'s for a 26.5" draw length. I love these threads like this where you can see actual data. I did the same on my set up going from 410 grains to 560 grains and was shocked at the difference. Keep up the good work and keep posting and letting us know your findings.

[haas0311]

Awesome stuff, and I agree with you mudslinger! These types of threads are awesome!!

[elkbowhunter]

right on target Mudslinger!!