Double Bevel, Single Bevel, Truth, Hype And Anything Else

[Doug S]

  "I think it was Howard Hill that started the 3:1 ratio concept. It certainly works for penetration, but the holes are too small"
   
Sums it up for me

[Ray Lyon]

The Ashby Study that so many talk about is so misunderstood.  The majority of the study is focused on maximizing penetration and breaking bone...not blood trails. Single bevel broadheads come in widths that range from the narrow 1" width that so many seem to despise to over 1.5", just like you find differences in double bevel widths.  We don't need to be scientists to figure out that a wide broadhead cuts more tissue than a narrow one or that a multi blade heads likely have more surface cutting area than a two blade and therefore opens a bigger wound channel for blood to exit, provided the depth of penetration is equal.  Single bevels, tanto tips, heavy arrow weights, high FOC are about maximizing penetration, not improving bloodtrails.  Dr. Ashby appears in many videos that can be found on Youtube where he discusses his studies, limitations of the study, and misconceptions that so many have.  It makes for interesting listening.

I will comment separately on my results and opinions on blood trails and effectiveness of two and three Bladen single pebble heads. I have to agree with the above that the Ashby studies were more about penetration and are truly misunderstood.  Years ago I had a friend who had some kids that he wanted to take bow hunting. They were using light weight Bear little Bear bow's around 25-30 pounds (I'm NOT advocating or endorsing, just illustrating).  I set him up with Easton Axis Jr. Arrows that had 2 blade Grizzly single bevel heads, steel inserts (225 grain total up front).  The kids got good flight with this setup and shot four white tails with two hole penetration on each. Shots were 13 yards or less from 10 foot platform. This was all about getting the most efficient arrow for penetration purposes and not about killing performance of the particular broadhead that this discussion is about.  The principal ideas of the Ashby studies were definitely focused on penetration.

[Ray Lyon]

So in my above comment, the 2 blade Grizzly broadhead used in the setup was part of the Ashby studies maximizing penetration.  Ashby was trying to maximize penetration on large game animals but the principles involved work as well with marginal weight setups for the application at hand (young archers and deer or older archer with lighter weight bow and maybe trying to tackle elk or moose). Skinny carbon arrows with higher front of center points will greatly increase your penetration.  A 3 to 1 length broadhead would increase that performance more, but if you're shooting a 40-45 pound bow with high performance string and using a carbon arrow with a little higher front of center (doesn't have to be extreme) then by all means use a wide two blade, narrow 3 blade or four blade head.  You will get plenty of penetration with clean flying broadhead arrows (a must with any setup). 

I've shot deer and bear with two and three blade heads.  I'm very good at sharpening heads and even my 3 blade Trailmaker heads will pop hair off my arm.  I've shot 3 deer with 2 blade Grizzly heads.  Many, many deer with 3 blade heads and two blade Zwickey Delta heads. 3 black bears, one with 3 blade Razorcaps and two with Zwickey Delta 2 blade. 
Bears-3 blade 35 yards. 2 blades under 60. All death moans. No tracking, either in sight or walked up to the direction of moan.  Hit a bear where you're supposed to and don't worry about what you're using if sharp. 

Deer-wide array of results but following generalizations:
3 blade-best trails but deer hightailed out! Can go up to 150 yards even if hit perfectly
Two blade Zwickey Delta- decent blood and under 100 yard recovery usually. Usually two holes no matter what.  One time I shot two deer fifteen minutes apart with two blade Journeyman concave blade heads.  Both deer ran about 70-80 yards.  NEITHER had complete penetration using 60# bow.  Didn't ever use concave head's again. 

Three deer with Grizzly head.  One ran thirty yards and tipped over. One walked away as if never hit and dropped in sight 60 yards (open woods). One ran 60 yards and heard it fall and thrashing so no "trailing", just walked to the last sound after a little wait. 
So there you have my general experience.  I will say I didn't notice a lot of blood on way to Grizzly shot deer, but it was certainly there.