What we know about broadheads

A simple question

How many blades should a broadhead have? Fixed or mechanical? The question comes up in every conversation about equipment, and anyone looking for an answer grounded in data ends up at the same three papers. All of them are cited by the authorities that decided, in Europe, whether the bow enters the law. We have read all three in full.

They give three answers that do not line up. Not because any of them is wrong, but because they measure different things, on different samples, under different conditions.

Madrid: 430 questionnaires

The Hannover study analyses 430 forms filled in by hunters around Madrid between 2011 and 2019, after bowhunting wild boar in urban areas and feral goats in protected areas. It is the only one of the three that measures two things at once: how far the animal ran, and how long it took to collapse.

Read on the means, the table says that the mechanical head gave the shortest flight and the longest time to collapse, and the two-blade head exactly the opposite. The author notes the mismatch herself: she expected the animals that ran least, on average, to also collapse soonest, and that is not what came out.

Before drawing anything from that, it is worth seeing how large the differences actually are. The median time is one minute in all three categories. The median flight distances for two and three blades are identical. The standard deviations are larger than the differences between the means: ±54 m for two blades, ±42 m for three, ±60 m for mechanical heads. The author’s own conclusion, in her summary, is that no clear relationship could be established either between head type and flight distance or between head type and the duration of the flight.

Norway: 69 questionnaires

Jørgensen’s thesis is a bachelor’s thesis from Evenstad, 2013, written under the supervision of two researchers from the Norwegian institute for nature research. The author sent out around 280 questionnaires, mostly through bowhunting federations in several countries, and got 69 back. That left 64 animals of 18 species: white-tailed deer, wild boar, impala, rabbit, pheasant, even a wildebeest and two musk oxen.

On that sample, the mean flight distance was 66.7 m for arrows with two blades, 44.5 m for three and 33.6 m for four. The statistically significant difference is the one between two and four blades. The author does not separate the species, but notes that the mean weight of the animals in the three groups was close: 73, 67 and 79 kg.

A necessary footnote, because the figures travel in a distorted form: the Hannover study credits Jørgensen with 44 m for two blades and 34 m for three. Those are his values for three and for four blades, shifted by one category.

Maryland: 1,296 deer

The 2014 article comes from another part of the world and measures something else: how many of the animals hit were recovered. The data come from a white-tailed deer reduction programme on a naval facility in Maryland, from 1989 to 2012, with 209 participating hunters, all of whom had passed the IBEP course and an annual shooting test. Of 1,296 animals hit, 1,083 were recovered, that is 83.6%.

Mechanical heads were only allowed in the programme from 2007, and the comparison that followed shows better recovery rates with them than with fixed heads, both for compound bows and for crossbows. The 2008 article, covering the first eighteen years of the same programme, when only fixed heads were allowed, had given 908 animals hit and 746 recovered.

Three measures, not one

This is the heart of it. Flight distance, time to collapse and recovery rate are often treated as if they said the same thing. They do not. On the Madrid data, the same heads come out in opposite order depending on which of the first two you pick. And the recovery rate depends on more than the head: on the tracking dog, on the terrain, on how long the hunter waits before following up.

So the honest answer to the opening question is that none of the papers read gives one. One finds an advantage for heads with more blades in flight distance, another an advantage for mechanical heads in recovery, and the third, the only one with both measures on the same dataset, finds no clear relationship.

What the law decided

There is one more reason we do not know more, and it is a legal one.

When the Hannover study wanted to compare the Spanish data with the Danish, it could not make the comparison by head type. In Denmark, two-blade heads are not allowed for the game the data covered. The rule is not new: the 1999 order, the one that opened bowhunting in Denmark, already required at least three blades and 25 mm for roe deer, fox, hare and goose. The Danish weapons order, in force today, keeps that requirement and adds a fixed head for red, fallow and sika deer; the rest of the figures are on the Denmark page.

In a country that has gathered one of the largest bodies of data in Europe on bowhunting, the law settled in advance what could be studied. This is no criticism of the rule: it was written to protect the animal, not to serve research. The effect stands all the same: the question about blades cannot be answered from the Danish data.

What could still be learned

Since 1 January 2024, anyone shooting at red, fallow or sika deer with a bow in Denmark must report every arrow released digitally, and the report includes, among other things, which type of bow and which type of arrow was used. A dataset is therefore being built that holds exactly the variable that was missing. Whether it will also be analysed that way, no text we have read says.

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