Quote from: Terry Green on October 16, 2025, 02:00:18 PMZwickey Delta 4 Blades since the 80s

I have also killed the random animal here and there with Sponsors heads from time to time. WIDE 2 blades and 3 blades.

My 2000 pound plus bison was killed with a Wensel Woodsman.

Never killed anything with a single bevel.  See no need to try.

I gotta echo Terry's post here, only I did try and kill hogs with a single bevel head on one of my Texas hog hunts... I got complete pass thoughs on both of them, but no blood trail to speak of. I'm quite certain I killed two hogs I never found. Once I went back to a 3 blade, the difference was huge. Much better blood trail. I have killed a lot of critters with a 3 blade woodsman broadhead, but grizzly makes a damn nice 3 blade 3:1 shape too that is outstanding.  You guys can have your two blade broad heads. I can't see single bevel or double bevel making a lot of difference to me.

3 blades = more blood on the ground.... Period.

I remember when Dr. Ashby's research was new to me and was being discussed quite frequently here and on other boards.  It dominated discussions on which broadhead to use.  Rt or Lt bevel and matching fletching to the bevel of the head, etc.... I bought into some of the hype and got some grizzly heads.  I think they are great heads and will do the job well if placed in the right spot (same as most any other head).  But I want to discuss some ideas in research as they apply to this discussion.

Almost all studies, that are worth any value, will have a statement about its findings along the lines of "within the limitations of this study...".  Its a nod to the fact that all studies have some limitation or limitations.  Science is rarely settled because of these limitations.  There is almost always a variable that is left out or cannot be included.  Sometimes the variable is minor and sometimes it is major.

In research studies that are worth quoting, you must have a control.  In these studies, Dr. Ashby used different heads as pseudo controls.  I'm not sure he ever established that one type of head was the "gold standard" and was therefore the control head.  All research would be conducted as a comparison to the control.  He compared several heads without really establishing what the best "accepted" head was.  And one reason for that is that there is no real gold standard.  Its a very subjective area.

The second issue was bias.  He admitted this in some of his writing.  Good research starts with a null hypothesis.  In other words, the research should start with the idea that the item, procedure, etc... is no better or not more effective than the accepted gold standard you are comparing it to.  You shouldn't start any research project with the idea that the "new" item/procedure is better.  It adds bias. 

Third, and maybe more importantly to me, the biggest limitation is the use of a carcass vs a live animal.  Now, I understand that a study on live animals would never get approved but any reference to lethality is merely an assumption in a study that can't show it.  You can infer some things from these studies but there is no real data to suggest a difference.  In order to do this, you would have to take live animals and use a broadhead of each design and shoot it into a live animal of the same species and almost exact proportions from the same bow from the same distance from the same shooter in the same altitude, barometric pressure, etc... (you see where I'm going with this).  Until you do, you cannot say one is more lethal than the other.

These studies being carcass studies, you have to make assumptions from the data on lethality.  Same thing goes for lethality studies of common handgun calibers.  Some say, .45, some say .40, others are good with 9mm and some say .380 won't work.  But there are studies that will show a .22 is enough for self defense.  Surveys of some surgeons say they can't tell the difference between calibers on the operating table.

While we can draw the conclusion that a single bevel head is better at bone breaking than other types of heads on a carcass, we cannot draw that same conclusion about lethality because it wasn't measured. You cannot measure lethality on a carcass.  You can make assumptions and you can design further studies from it but its not a cause and effect relationship without all the data.  What we are left with is empirical data or data based on our own experiences and observations.

We hear all the time that light bows aren't enough.  Double bevel two blade heads aren't enough, etc.... Truth is, empirical data tells me they both work.  I've seen complete pass throughs with a 35-40 lb bow using two blade double bevel heads with good blood trails.  Just as we have all seen it with multiblade heads.  I have also seen poor penetration with the same setup.  I've watched videos of compound shooters shooting a well set up and tuned bow get minimal penetration that was lethal sometimes and sometimes not.

So, in sum, what we know empirically is sharp heads shot accurately into the vital areas of a game animal can be lethal.  I think we can empirically say a passthrough shot is better for tracking but not necessarily more lethal.  I think we can say multiblade heads give us a different wound channel.  We can say these things based on our experience or observations.  There is no doubt, from some of the photos we've seen on here of the exit wounds made by simmons heads, they can be devastating.  But those are not all the exit wounds that exist.  Same for 3 and 4 blade heads.  I've hunted with Terry and have no doubt those Zwickeys are lethal.  Its hard to argue their effectiveness when shot by a competent bowman into the vital section of an animal.  So, what I'm saying is, you do you and I'll do me.  In my world, I'm ok with two blade double bevel heads like the Simmons Sharks, Zwickeys, STOS, and 3 blades like the woodsman, VPA, and 4 blades like the Zwickey, Phathead, etc..., or two blade single bevel heads. Width is another variable that must be evaluated, but that's another post.  Get them sharp, shoot well, and eat up.

P.S. I should say that I'm with Terry on this.  If it isn't already obvious, I'm not buying the hype on narrow, single bevel heads.  I think they are effective but I don't think they are more effective than the other heads I can shoot.