RE: Ethical Arrow Weight
 

Absolutely correct.;) If his chrono is off that much, though....I'd wonder about his scale![8D]

RE: Ethical Arrow Weight
 

dont forget momentum into the factor......

i'll take a heavier arrow moving slower than a faster, lighter arrow every day for hunting. it will carry its energy better

momentum=MASS+VELOCITY

a 350gr arrow doing 305 fps has a momentum of 106750 and a KE of 72.31

a 450gr arrow doing 260 fps has a momentum of 117000 and a KE of 67.56

thats roughly my bow for IBO setup vs what i really shoot....i loose some speed..and loose a few pounds of KE, but i gain a good bit of momentum...it will be harder to stop my arrow vs the lighter, faster IBO arrow.

i played with numbers for a while to find the point where i have the fastest arrow producing the most KE...then found arrows that fit the bill. (i like math and numbers) i found that any heavier just takes away speed but doesnt do much for KE...i found it to be a nice arrow weight for my setup...though heavier will add more momentum...

my point is KE isnt everything...though were talking deer that weigh less than 300lbs and if shot in the vitals, dont really have anything that is tough....hide, muscle and maybe ribs, which break and bend fairly easy...

RE: Ethical Arrow Weight
 

Explain this part to me, Mauser. I have a hard time following these "momentum" arguments....and I'd like to understand it better.

A heavy arrow is harder to stop than a light arrow moving at the same speed. A faster arrow is harder to stop than a heavier arrow moving at a slower speed. These are generalities.....butThe KE formula figures out which one is "better" for us. I'm not sure "momentum" is understood enough. I know I'd like to know more about it....and why it belongs in the same sentence with KE.

RE: Ethical Arrow Weight
 

I wasn't implying those numbers are not possible...just that they are not common or "starting points". Even if the chrono and scale are off in your case, you are more than adequate for most game. I would guess your bow to be more around the 275 mark...but that isn't something I even check on my own setups normally.

RE: Ethical Arrow Weight
 

I agree that momentum has it's place no doubt, but for ME I would have stopped in there somewhere in the middle of the two examples you posted,where the KE peaked and I would still have more than sufficient momentum!!!! When I am setting up arrows and adding weight I look for the point right before the KE falls, at this point I feeltheset up is at it's best performing point, a good balance of speed, Ke and momentum!!!! Like you said you can't focus on just one part of the equation!!! That's just my .02, I feel a good balance of all three is great hunting set up and it has worked very well for me for many years.

RE: Ethical Arrow Weight
 

Mauser, FWIW below is the formula to be used when mass is measured in Grains:





Momentum = Mass x Velocity
225218

This is expressed in slug-feet per second.

For example, my Bob Lee recurve shoots a 670 grain arrow at 175fps, momentum is .521 slug-feet per second.

RE: Ethical Arrow Weight
 

How many slug-feet to shoot mechaincals, Bob?:)

(sorry....I hate it when i do that;))

RE: Ethical Arrow Weight
 

Never tested them myself...

I not sure if anyone ever really has. I know that Dr. Ashby tested (not on deer though) some of them (mechanicals), but Ibelieve that his number one determinant of penetration is arrow and broadhead integrity (including components). I don't believe that any mechanical head past this. I believe his second is broadhead mechanical advantage which I don't believe mechanicals passed either. If you're interested on researching, I could show you where to look.

RE: Ethical Arrow Weight
 

I was actually just kidding;)

I only hunt deer with mechanicals....and the integrity and penetration is fine for them.

Interested in what materials he was testing on for penetration and integrity, though.....if it wasn't flesh, cartilage and inconsequnetially small diameter bones.

RE: Ethical Arrow Weight
 

Big game animals, African mostly, I think.