You trying to insult my intelligence by repeating like is like very funny. I'm like totally embarressed now.

i never said you change multiple variables.I stated that you must try other variables for a valid test to be conclusive. Without tryingmore than onevariable and only looking at one aspect you are not doing a valid test. Sure you prove one point. But still leaves the door open for everything that you ignore in the test.

Here is a meaningful test to me. Start off with everything the same with exception of weight. Then, you change a variable like diameter of the lighter arrow. Then, you change another variable and so on. This does not muddle the waters. It clears things up and gives a good picture. Ashby actually does that with his tests.

Of interesting note from Ashbey is concering extreme FOC arrows. Specifically carbon. Arrow Lethality Study- 2005 2005:
Quote:
"All indications are that extreme FOC arrows do, indeed, offer a substantial gain in arrow penetration...... what little data at this time is suggestive that only the flexional characteristics of carbon shafts allow one to achieve an extreme FOC while maintaining good arrow flight" And later ... that it may offer highly significant gains in penetration when boradhead/arrow integrity are maintained."

This sort of testing by Ashby gains a great deal of respect from me and is of something that should be noted and of worth to people who like to use lighter arrows.

This probably explains why companies like CX are now making arrows with weight forward design. They've realized that a weight forward arrow offers better penetration. I believe another manufacturer also offers 25 gr screw-in inserts for carbon arrows.

Relative to Dr. Ashby's data on penetration and FOC. I read that also. That sort of data is convincing indeed. I plan on shooting an "extreame FOC" setup for hunting. I also plan on finding a broadhead with the maximum mechanical advantage. After all, hard data is hard data.

You are right, I am a funny guy. But if you are embarassed you really should work on developing a "thicker skin"!

Bob, the only thing I am saying is that with my particular bow it seemed to perform best with an arrow weight of around 450 grns, irregardless of spine, diameter or type of arrow. I tried several different arrows from 300 to 600 grns. The 400 and 450 grn arrows did the best for me. Once I got to around 500 grn the penitration started to taper off again.

I don't know what it means to be honest. Other than my bow seems to like 450 grn arrows the best. I have noticed when using a ballistics calculator that when arrow weight increases beyond a certain point Ke starts to drop again. Momentum pretty muchs keeps rising, but Ke will start to taper off again. So I can only assume that penitration must have something to do with both Ke and momentum.

Arthur that is a pretty cool device. I hadn't thought of one that swings. I was thinking something along the lines of a set amount of weight on some rollers or bearings. And when the arrow hit it I could measure how far back it would move. I really wasn't looking to gain any hard data as far numbers go, just comparing arrows to each other is all. That looks much more simple to build though. Thanks for the link.

Paul

A broadhead like a Muzzy or any other cut on impact broadhead is more than sufficient for deer or most game for that matter. They are proven. The replacable blade broadheads from 20 yrs ago had something to be desired though. I think that the manufacturers have learned and adapted. I guess you think you are proving your point with the hard data is hard data comment? When I read his article I see what might help my current set-up. Not think that I need to take all of it as gospil. By him stating that a extreme FOC light arrow outpenetrates a reg FOC by 50% doesn't that negates the heavier arrow will penetrate more because of momentum.

That's called sarcasm. I have very think skin. Your reply tells me you do not.

I'm jumping thru Ashby's report. Does he compare weight forward arrows to the heavy arrows he shoots? Also, when one of you said that he considered 650 gr broadheads I thought you were kidding. But he actually says that.

I guess if I was hunting something like a Cape Buffalo I'd make sure I had big equipment. Of course, I would use something like a rocket launcher amd maybe Special Forces as back-up if I hunted buffalo. Those guys are crazy to sneak thru the brush after something that dangerous.

You may want to read this page: http://www.tradgang.com/ashby/2005update6.pdf

and this one, which is very good:
http://www.tradgang.com/ashby/2004update2.pdf


and another very good one for his overall explanations:
http://www.tradgang.com/ashby/2005update5.pdf

He has many different studies going on, and it actually takes a long time to read them all and understand them. I have. When done, I really don't see how anyone can disagree to any great extent with his methods or conclusions. They are far and away more in-depth and thorough than anything else out there.

When done reading this, you will see that he finds absolutely no correlation between penetration and KE. He also finds that momentum is only a starting point. He demonstrates clearly that heavy weights are king for penetration and that arrrows that derive their momentum from mass vs. speed are clearly better penetrators, even if momentum is the same. He also points out that even though extreme FOC is very important to penetration, that only heavy weight will give "bone breaking" impacts. Speed will not do it, extreme FOC will not do it. He even demostrates that a 700 grain arrow shot out of a 55 lb bow is almost as effective at breaking bone, as the same arrow shot out of a 70 lb bow. He concludes, the overiding factor is weight over 650 grains. He also states that extreme FOC arrow appear to lower this bone-breaking threshold only slightly.

I have his latest update on my desk at work. I'm disagreeing that I need an arrow over 700 grains for deer. Or 400 for that matter.

I deffinetly have to agree with dave on that. For deer, no way in h*ll you need a 400 grain arrow. Elk yeah maybe but for any animal that walks in north america a 400grain arrow is more than enough to do the job.

Good grief, for about the hundredth time, we're not talking about what is adequate to get the job done. We're talking about what's the best way to get the job done. Only fool would say you can't kill a whitetail with a lightweight arrow. Sure you can, but it's not the best weapon - period.

Straightarrow, Im not sure how you come up with what is "THE BEST WEAPON".If we are talking about deer, andan arrow thats zips through a deer, sticks in the ground behind it, is shooting over 300 fps and getting flat trajectory to aid in misjudging range. I would agree with you, but since your talking about a heavier arrow that is going through a deer, shooting slow, not having a flat trajectory, and doing everything the lighter arrow is doing minus the flat shooting part Ill have to disagree with you. On deer size game I think your a completemoron if you have the mindset that you have to have a heavy arrow to do the job efficiently. I would deffinetly lean more towards lets say a 400grain arrow for elk or game larger than that, but for deer and antelope there is deffinetly no need.

Just for the record, you are obviously not a complete moron!

Adequate? I have some data that indicates that a deer can be killed with a .22 (actually I killed my first deer with a .22). So from that perspective,might oneconclude that a .22 is an adequate weapon for deer?I'm not sure about a lot of things. However, of the things that I am absoultely certain of, when in the process of harvesting gamethere is no such thing as too dead, but there is for damn sure such a thing as not dead enough!

Asfor Dr. Ashby's work it would appear to me that it is the most comprehensive in terms of methods of data collection, amount of data, data analysis, andscientific rigor, of any work of it's kind,mostprobablyin the world. Until I find something better I will use his work asa resource in determining for my set-up,not an adequate choice to do the job, but the best choice to do the job.