Bowhunters expect a lot out of the broadheads we shoot. Accuracy and integrity are two big ones but penetration is the factor where we win or lose. Rather than listen to the marketing and advertizing chatter I decided to do the science and see how some popular heads performed. I had the slow-motion camera set up to film the test in the shooting lab.
My plan included shooting broadhead tipped arrows into something that would be impossible to penetrate. I know from experience that plywood with its multi-directional layers would be a challenge. I decided on two layers of plywood sandwiched together with C-clamps. One sheet was ¼ inch and the other ¾ inch. That’s a full one inch of plywood.
Next, I set up a shooting machine at 16 yards shooting a 70# EVO and shooting PSE arrow shafts. All broadheads were 100 grains. I gathered some of the best broadheads both fixed and mechanical for testing.
For a backstop, I arranged 250# of aluminum ingots into a tunnel so the face would support the plywood from top to bottom. It was important that the plywood not move upon arrow impact. This allows the target to absorb all of the arrows energy. Now I was ready.
I first chose to test a Swhacker mechanical two blade. This broadheads design and engineering is unique among mechanicals. It utilizes a two-stage deployment. First, two chisel sharpened blades, one inch wide, cuts through hide muscle and bone… then big scissor blades open to deal with the vitals. This engineering allows for programmed use of momentum and kinetic energy. It’s a design the manufacturer contends enhances penetration. Talks cheap, let’s do a test.
I cranked back the bow to full draw, nocked an arrow and counted down…3,2,1, shoot. The impact was a loud as a rifle shot. Sounded like there must have been a big collision. As I approached the test table, I noticed that the arrow had penetrated enough to hold the arrow stable. Then I began to disassemble the set up enough to examine the plywood.
This was impressive. The broadhead had fully penetrated the 1-inch of plywood and the scissor blades were deployed. Those scissor blades had deployed about ¼ inch before the blades blew through the back of the plywood. Wow, we had blades fully deployed and totally intact, not even bent. The bone chisel blades had done the job. That Swhacker broadhead design actually did program the use of energy.
The way I see it that is a big benefit for a bowhunter. I often shoot bears, caribou and elk with broadheads and that plywood test resembled the shoulder blade of a big game animal. An engineering package that sequentially opens blades to allow for big bones is a good idea. It certainly contributes to penetration.
Next, I decided to follow through with my testing and try other popular heads on the plywood. First, I tried the most popular mechanical, one that opens on impact. I shot it at the same plywood but at a different spot. Whack! The impact sounded the same but upon inspection; I found that it failed to penetrate even the ¾ plywood. To be fair, it did get about half way through and should probably get one star. However, why did it fail to penetrate?
A little high school physics told the story. They had designed it to open upon impact and sure enough, it wasted its energy in the first ½ inch. Those blades were busy cutting from the moment they hit the wood. The kinetic energy, which could have been used to promote penetration, was used to make a surface cut. A flashy idea but not one that delivers penetration.
Next, I tried a popular rubber-band three blade mechanical and it got jammed up while trying to open the blades after they were already in the plywood. The same thing would probably occur on bone. Not a good plan for penetration.
I shot 4 or 5 other mechanicals at the plywood and not one made it through. Same bow, same distance and same arrow, the difference was the engineering of the broadheads.
To be fair I thought I’d try a fixed blade broadhead. I figured it would probably blow right through the plywood. In addition, it only cuts a small amount of tissue. Here we go. I shot it into the plywood and to my surprise, it was a no-go. The tip dimpled the plywood but no blades made it through.
So what did I learn? For one thing, don’t buy into the celebrity TV marketing. However, the most important thing is that engineering matters. The programmed deployment used by the Swhacker allowed the bone chisel blades to cut a one-inch path through a full inch of plywood and achieve total penetration through a very demanding target. Then the Swhacker deployed the razor sharp scissor blades where they are needed.
That’s the penetration story. Poor penetration means you lose. It’s the science on one of the most critical performance features bowhunters look for in a broadhead. It’s a feature you should demand in your broadhead. You only get one shot. Watch the plywood lab testing on BOWTUBE. GO…