Penetration tests for low KE setups
BROADHEADS FOR LOW DRAW WEIGHT BOWS
When most of us pick a broadhead, we weigh the balance of accuracy, cutting diameter and penetration potential. Most adult males are pulling enough draw weight, with a long enough draw length that for the most part penetration is not hard to achieve, even with some of the larger mechanical heads. On the other hand, women bowhunters, along with younger children and those suffering from injury often times are restricted to lower poundage bows with shorter draw lengths. This greatly reduces the amount of Kinetic energy they are able to produce. Since penetration is directly related to Kinetic energy, along with momentum, bow tune, and broadhead size, these bowhunters have to pick their heads carefully to maximize the amount of penetration they will achieve. An arrow need not pass through a big game animal to kill it efficiently and quickly, but it does need to be able to reach the vital organs with enough cutting surface to effect a quick clean kill. To this end I conducted a test using a 24” draw length bow, set at 40lbs shooting a 420 grain arrows at an average speed of 163 fps. The total kinetic energy was 25 ft/lbs. The bow was tuned well, shooting bullet holes through paper at 3, 8 and 15 feet. It also shot nice tight groups with all the broadheads tested. All shooting was done at 20 yards. I chose to shoot two different types of test materials. The first was a ¼” piece of solid wood paneling cover with a thin rubber mat. Directly behind this was a brand new “Cube” broadhead target. The 2nd material was the cube target alone. I shot the opposite side to keep the test as consistent as possible. For each test I shot each head three times, for a total of six shots. I then averaged the total of the 6 shots, as well as the totals for each test material. Some heads did better in the hard board/rubber tests while others did better in the soft foam alone.
I need to say this now, these tests do not in anyway indicate how these heads will perform on game. They only show how they compare to one another when shot from the same bow into the same materials. You will notice that there is an average of 3 inches difference between the best and worst heads. This seems small, but with low energy setups every little bit counts. I chose these heads because they have all done well in my regular tests. I tried to pick a wide cross section heads. They range from 4 blade chisel tips to smaller mechanicals and also include 2 blade, cut on contact styles. I also tested one un-conventional head in the Mar-den Swinger. This is a large 1 ½” two blade that pivots when it strikes something hard. When the blades contact resistance the O-ring is pushed off allowing the blade to pivot to the side of least resistance. The idea is sound, but my tests really did not provide for a fair test of this head. It will perform best when the material is not “uniform”. Ribs and bone in animals are separated by soft tissue. My test materials are solid, so the Swinger really had nothing to “swing around”. That said they did do fairly well, especially compared to several other conventional style heads that are commonly recommended for low energy setups.
You will notice that 2 of the top 4 heads in the in the overall rankings are mechanicals. Also those two heads are ranked 3 and 4 in the “soft” material category. I found this somewhat surprising, but not totally unexpected, as these two mechanicals have proven in other tests to penetrate as well as many fixed blade heads. Also surprising was that several two blade cut on contact heads, which one would normally expect to penetrate the best, actually ranked below other heads that conventional wisdom says would not penetrate as well.
What I am finding more and more is that smaller shorter, lower profile heads tend to penetrate better, regardless of the style. In other words just because a head is a cut on contact does not mean that it will out penetrate a chisel tip head, or that just because a head is mechanical, doesn’t mean that it will penetrate less than a fixed blade broadhead. The total combination of the length, width, and number of blades seems to be more important than the style of tip, at least when considering performance in my test materials. The bottom line when it comes to penetration, smaller is better, provided you still have enough cutting surface to get the job done. Below is a listing of how each head did in the separate categories as well as the total rankings. All measurements are in inches and are an average of three shots.
HARD MATERIALS:
1. Rocky Tradition-6.37”
2. Rocky Ironhead XP-4.25”
3. Magnus stinger- 3.00”
4. Muzzy 4 blade-2.87
5. Wasp Boss bullet-2.75”
6. Rocket Steelhead- 2.37”
7. Mar-Den Swinger-1.75”
8. Magnus screw in-1.12”
SOFT MATERIAL:
1. Wasp Boss Bullet-9.50”
2. Rocky Tradition-9.37
3. Rocket Steelhead-9.25”
4. Rocky Ironhead XP-8.87”
5. Muzzy 4 blade-8.50”
6. Magnus Stinger-8.12”
7. Mar-Den Swinger-8.00”
8. Magnus Screw in-8.00”
TOTAL RANKINGS
1. Rocky Tradition- 7.87”
2. Rocky Ironhead XP-6.56”
3. Wasp Boss Bullet-6.12”
4. Rocket Steelhead-5.81”
5. Muzzy 4 blade- 5.68”
6. Magnus Stinger-5.56”
7. Magnus screw in-4.56
8. Mar-Den Swinger-4.87”
*All heads tested were 100 grains in weight. The Stingers were the two, blade version. The Magnus, screw in heads, were the vented two blade. *