Steve — I totally respect whatever it is you’re saying. But as a math idiot, I haven’t a single clue.:shock: But so long as whatever knowledge there is to be learned here leads us toward deep penetration and fast clean kills with high recovery success, I’m all for it. All I know for sure in the energy vs. momentum argument is that when I shoot light arrows into elk, not matter how fast, they don’t penetrate worth poop even in soft flesh, and I once had once bounce out of a shoulder hit! But when I shoot really heavy arrows, no matter how slow, they go all the way through, and even through heavy bone. To me it has always seemed that the “energy” fans are trying to justify longer shots. So again, I know you’re a very good guy and thus must trust that this study or whatever you are recommending adds knowledge to those smart enought to understand it. But down here on my level, I’ll just keep shooting really heavy arrows with what Ashby calls “high mechanical efficiency” broadheads, and get as close as I can before doing the deer. In the end I don’t think it matters so much who or what is right or wrong, but only what works best for us on the animals we hunt. Kill ’em fast and kill ’em sure. That’s what anyone who even counts for anything really wants. I hope you know this is no “argument,” with you at all, but just trying to say that … well, we speak different languages and need them all. As someone said, sort of, would you rather be hit in the chest by a light weight dart traveling really fast, or a big heavy spear going much slower? I’ve tried both, many times over, and for my conscience will go with the spear. Homer

I’m no physics geek, but it always seemed to me that focusing solely on kinetic energy, without factoring in momentum, was missing half the equation. An approach that integrates both makes a lot more sense to me.

Then again, theory only gets you so far. The third half of the equation (lol), and arguably the most important one, comes from real world experimentation, which sometimes seems to fly in the face of theory.

Stumpy’s Postulate states that: heavy, sharp and fast beats any combination that substitutes light, dull or slow for one of the three variables.

Notice that the article first came out in 2000, yet, there is nothing else out there concerning this idea. There is a reason why this idea never went anywhere. Its basic premise that you can arbitrarily multiply momentum and KE and thereby derive a relevant relationship is fatally flawed,
Look at the first example where the author “derives” a bullet applying a force of 15984.6 pounds to a target. Personally I’m going to stick with standard Newtonian physics where for every action there is an equal and opposite reaction. What do you think would happen if your rifle applied a force of 15984.6 lbs. to your shoulder every time you fired?
Sure, its all very logical, and the math sure is impressive. Too bad its all based on a false premise.
Yes its applications would be severely limitted…..To an alternate Universe!:lol:

Steve Graf wrote: If experimentation and theory don’t agree,… then a new theory is needed… 🙄

Precisely! A theory is a theory, because it’s not accepted as fact. Once proven wrong, by any means, it’s no longer a theory. Well, there are some things that have been proven wrong but we still accept them, but I digress… 🙂

I have only been hunting with bows since 1971 and the only theory I stand by is, Practice. If you can’t put a razor sharp broadhead in the boiler room then you have a long tracking job ahead. Funny though how tracking/blood trailing have gone out the window. “I looked for an hour and couldn’t find the animal. Oh well, there are others.” That said I do use heavy arrows because of my own experimenting. Carbon arrows make my bow noisy and don’t fly as far as aluminum. Aluminum aren’t as noisy but are noisier than my woods. My tapered as make my bow much quieter and the fly further than carbon and aluminum. Out of curoisity I shot a carbon an aluminum and a wood arrow for distance. The wood went the furtherest. Why? Because the wood arrow uses up more of the bows stored energy than the other two. My arrows weigh in at approx. 675 grn. I use a 160 grn. razor sharp broadhead and lots of practice.

Sorry for rambling and hope I haven’t bored anyone. Just my $1.50.

Smithhammer wrote: The third half of the equation (lol), and arguably the most important one, comes from real world experimentation, which sometimes seems to fly in the face of theory.

Steve Graf wrote: If experimentation and theory don’t agree,… then a new theory is needed… 🙄

Patrick wrote: Precisely! A theory is a theory, because it’s not accepted as fact. Once proven wrong, by any means, it’s no longer a theory. Well, there are some things that have been proven wrong but we still accept them, but I digress… 🙂

That statement was meant tongue in cheek. Well, mostly.

Lots of people have agreed that assessing arrow penetration capability based on KE is the way to go. That doesn’t necessarily make it an accurate premise, as we’ve noted. Yet it’s become a standard way of looking at the issue. Sometimes we let theory dictate results, or at least our perception of them.

You can theorize till the cows come home, but once you introduce the human element and myriad other real world variables, broad theories only seem marginally useful to me over first-hand experience with the actual equipment you’re using. If the experimentation yields the results you’re looking for (which might work great for me and not at all for someone else), then the theorizing is optional, imo. Personally, I’ll leave that to those who enjoy theorizing, and stick to what has already been well-determined, combined with personal experience.

Polar Bear wrote: I have only been hunting with bows since 1971 and the only theory I stand by is, Practice.

Exactly.

Polar Bear says: “I have only been hunting with bows since 1971 and the only theory I stand by is, Practice.”

With all due respect, Bear, practice isn’t a theory and accuracy is an entirely different topic than the physics of arrow penetration. It’s apples and oranges and both are important and worthy of detailed discussion. IMHO Homer