Fixed Blade vs. Mechanical Broadheads

By

And So the Debate Rages On.

Which do you prefer? (Bill Konway/John Smith/Shutterstock photo illustration)

My response to the broadhead debate has always been simple: The fixed-blade broadhead wins every time. Today, however, my opinion isn’t so cut and dry. With more and more effective mechanical designs hitting the market, this style of head has become a serious consideration for me and other bowhunters.

I have no qualms going after three-quarters of the game I hunt using a good mechanical head. Yet, when that special hunt of a lifetime is suddenly on the line, especially for large deer or elk, and my bow is spitting out fixed heads into tight clusters at extended range, my sixth sense tells me to load up the fixed blades and don’t look back. It comes down to this: Why take a risk with something that “scissors open,” when I can send a fixed package—it leaves my bow the same way it arrives on target—for the ultimate killing guarantee.

Rather than relying on emotional feelings to solve the timeless broadhead debate, let’s take a look at the cold-hard facts behind broadhead design.

Mechanicals: Surface Matters

Blade surface area is what hurts fixed-blade heads from flying accurately. From a poorly tuned bow, such heads usually spell disaster, particularly when arrow speeds reach 265 feet per second and beyond. This disaster leads to much frustration and loss of killing efficiency.

Choose the right broadhead for your setup. (Josh Honeycutt photo)In comes the mechanical head. With little to no exposed blade surface in flight, these closed-in-flight bladed tips move through the air with little to no aerodynamic drag—which allows the rear of the arrow (the fletching) to do the steering part, instead of creating guidance issues where the front of the arrow wants to steer as well—a phenomenon known as “planing.” As a result, deviations in arrow flight (caused from a poorly tuned bow or a rough release) don’t send the arrow off course, which maximizes forgiveness and the ability to hit what you’re aiming at.

In today’s world where convenience seems to be everything and “extra time” is increasingly rare, the mechanical’s ability to put you back on target—instead of forcing you to spend countless hours adjusting your bow and paper tuning—is simply too good to pass up. This is why mechanicals will always have their fans.

However, the mechanical head has not always delivered killing efficiency like one would expect. Many of these heads are fragile, with less-than-effective blade mechanisms, which cause them to either come apart at impact or retard penetration so much that in the end they don’t cut and create a lethal wound channel for a quick, humane kill. Regardless of how accurate a broadhead is, it must stay together and it must penetrate deep, otherwise it’s worthless.

Much of the mechanical’s shortcomings have been minimized or solved thanks to insightful engineering and the use of higher quality components. One key is how the blades open on impact. Some operate much better than others.

My favorite models “cam” or slide open, which eliminates the chance for “kick-out,” which can happen with “jack-knife” style mechanical heads that have blades that are supported at the bottom and rotate open from the front-back at 90 degrees.

Fixed Blades: Awesome Reliability

Strength, not flight performance, is the fixed head’s most attractive feature. I laugh when mechanical head manufacturers or their reps tell me how their heads are as tough as a fixed-blade. Physics tell us that this is impossible. A fixed head comes with blades that are supported their entire length, not just at one point. Also, by design, they are simpler with no moving componetry. A moving mechanism made of the same material and of size is always weaker than a non-moving one—really, an indisputable fact of engineering.

I’m not saying a lousy fixed head is stronger than a top-quality mechanical. What I’m saying is that when comparing apples to apples—a well-made mechanical and a well-made fixed head—that the fixed head is without question stronger and more reliable at staying intact, despite impacting rib or shoulder bone.

Also, thanks to relentless innovation and design, today’s fixed heads are also quite aerodynamic and yield excellent flight characteristics. Can they match a mechanical’s flight performance? Generally speaking, out of a well-tuned bow, I believe they are every bit as accurate. I think some of the best, most streamlined mechanicals are slightly more accurate than any fixed-blade head. And I think that many top-notch fixed heads can outshoot a poor mechanical, simply because some mechanicals fail at keeping blades “closed” during flight, which causes all kinds of flight inconsistencies and loss of accuracy.

Last year while performing some accuracy tests for my book, Technical Bowhunting, my engineering friends and I discovered how certain arrows were hissing more than others in flight, despite using the same arrows and fletching. Eventually, through a bit of trial and error, we identified that two styles of mechanical heads had blades that were opening somewhat in flight. After using additional rubber bands to secure the blades, the hissing stopped and arrow groups shrunk to nearly the same size as arrows tipped with field points. That phrase we always see on mechanical-broadhead packaging that says, “They fly just like field points,” really isn’t always true.

Un-Blurring the Facts

In a nutshell, these are the truths that can make or break each kind of head:

Aerodynamics: When testing mechanical heads, be sure to shoot them repeatedly through tissue paper to see if they are opening prematurely. If so, they will plane and fly erratically no different than a large fixed-blade head used with a high-speed arrow or a poorly tuned bow. I would steer clear of blade systems that don’t stay shut.

High-speed takeoff or flight is not what causes blade deployment, but involves a concept known as centrifugal force, otherwise known as rotational speed or turning of the arrow as it flies through the air. Arrows, especially the fast, light arrows of today, emit intense centrifugal force, which effectively “whip” open many mechanical blades. The greater the arrow speed, and the greater the spin of the arrow, the greater the chance for blade failure.

Another important variable to point out is broadhead flying ability relates more to overall aerodynamics rather than just overall blade surface area. I’ve proved this in a series of broadhead tests a few years back while testing more than a dozen heads. I found that some mid-size broadheads actually out shot a few of the more compact models.

The only way to determine broadhead accuracy is to shoot a lot of different heads and then measure group sizes.

Concentricity: This involves how precise and straight a broadhead spins on the shaft. In my opinion, top-quality all steel, one-piece ferrule/tip designs spin the truest (without wobble) from one head to the next compared to aluminum-ferrule broadheads.

Strength: In terms of durability, a quality fixed head cannot be beat. Some of today’s mechanical heads are well designed and use expensive heat-treated blades, which tend to bend instead of snapping off from harsh impact. However, I’ve found very few manufacturers to maintain the use of high quality blades continuously from one year to the next. It’s simply cheaper to use lower-quality blades, and consumers are unaware of it, so why not?

Even so, a mechanical’s blades are only supported at one end, usually held in place with one retaining screw. This makes the blades susceptible to breaking. I’ve seen it time and again, especially in elk camps as hunters held up a mechanical head with blades that were cleanly sheared off. Also, the greater the blade angle, the more intense the force placed on the blade(s) at impact becomes, which increases chance of failure.

Also, during high-speed impact, this retaining screw can take on an intense load once the blades violently deploy and snap back to lock. This force can cause the screw to actually give before anything else.

Last but not least, most mechanical heads still use aluminum ferrules, unlike most of today’s popular fixed heads, which use all-steel ones. Steel, of course, is much, much stronger than aluminum.

Angled Shots: Not all mechanicals are poor performers on angled hits. In fact, and this may surprise some of you, a well-designed model can actually penetrate better than a fixed-blade head in such scenarios. For example, during initial penetration, the entire length of the ferrule on some models must penetrate before its blades deploy. This positively seats the broadhead’s tip and about 1/3-length of its body, eliminating the chance of cartwheeling.

Some of today’s ultra-compact fixed blades with cutting widths around 1 1/8 or 1 ¼-inch can kick-out of the arrow since the inside blade can actually strike the target before the tip has a chance to penetrate. When this happens, force is exhibited laterally instead of vertically, which can divert the arrow from penetrating in a straight line, causing it to potentially ricochet.

I’ve witnessed “ricochets” in the field on numerous occasions, and now this tends to be my No. 1 concern when choosing a broadhead. Broadheads with longer, slender tips with blades a little further back will most likely perform the best on angled shots.

Penetration: Many “experts” say penetration really isn’t an issue with today’s high-energy/high-speed bows, which I think is boloney. Maybe if we used heavy 700-grain arrows like in the olden days it wouldn’t be, but with the use of much lighter 330 to 400-grain arrows, which are common arrow weights of today, lack of penetration is a huge issue!

Fortunately, most of today’s most popular heads, both mechanical and fixed, are super-sharp and incorporate low-friction tips and cutting angles. For me, I try to steer clear of broadheads with cutting swaths 1-½ inches or more. In some situations these big cutters make sense, but for most of my serious hunting across the globe, I prefer the reliability and deep-penetrating guarantee of smaller cuts. I favor 1 to 1 3/16-inch cuts for fixed heads, and no more than 1 ½ to 1 3/4-inch cut for mechanicals.

Other Issues: This may sound silly, but one of my main beefs with mechanical heads is this: When I lurk through the woods with an arrow nocked on the string, whether I’m still-hunting or during the last phase of a stalk, I often walk with my bow safely held to the side, at waist level. At times, when ground brush is a couple feet high, the broadhead will brush up against the scrub. This brushing can cause rubber bands to slip out of place and/or cause blades to fly open. This is a major distraction that requires movement to recapture blades and to realign O-rings. One time on stalk I jumped an animal and went to shoot but realized the blades on the mechanical head I was using were already deployed. Talk about an irritating nuisance.

The mechanical and fixed-blade broadhead debate will likely go on forever. With so many great choices available in both styles, it’s tough to know which way to turn. Hopefully this article sheds enough clear light to make the selection process a little more black and white for you. I know this—broadhead selection is not to be taken lightly. We owe everything to the animals we hunt. A quick kill is what it’s all about, and nothing determines that more than the business end of the arrow.

Click here for more bowhunting stories and how-to's.

Check us out on Facebook.