Lead is toxic to humans and the environment. This fact — rooted in solid scientific evidence — is the source of much debate among hunters and shooters. Many claim that the science isn’t settled or is wrong, oftentimes relaying personal anecdotes about how they’ve eaten animals shot with lead ammo for years and haven’t noticed any ill effects. Others attest that the notion that lead is toxic is merely a ploy to further regulate hunting and shooting sports. But the science behind the toxicity of lead is sound. Lead harms the nervous and reproductive systems in the human body and accumulates in and harms animals and their ecosystems. Really, it isn’t something we should be tossing into the environment in large quantities. It also is certainly something we don’t want to be eating.1
In response to its proven toxicity, lead ammunition is in the process of being slowly phased out. However, when lead is phased out, other materials will be phased in. How safe are these primary substitutes and how well do they work? Are non-lead bullets toxic too? I wanted to know the answer to these questions to make sure that I could harvest wild animals humanely while minimizing ammunition-based contamination of the meat and the environment. Unfortunately, some of what I found in my research is rather concerning.
This is going to be a ‘living’ post. The science of toxicology and the materials used in ammunition are constantly evolving. As a result, I’ll try to keep this page up to date as any new information comes across my desk.
The Lead Ban Controversy
I don’t really want to go too much into this as it’s a real hot-button issue, so I’ll leave only a short note here. Lead has been used in hunting for centuries and performs admirably in bringing down game. Its density and malleability give it excellent ballistic properties, which I discuss below. Lead is also relatively cheap. These facts have left lead as the dominant bullet and shot material.
However, lead has toxic effects, both for humans and for ecosystems. As the science on lead’s toxicity has accumulated, American policymakers have progressively eliminated its bulk use, especially where that use would produce lasting environmental contamination. For example, both leaded gasoline and leaded paints have been phased out in favor of their non-leaded counterparts. For the most part, these transitions result in technological adaptation and in non-lead products that eventually perform quite similarly to their leaded counterparts.
In keeping with the desire to end the bulk use of lead, policymakers’ attention has recently turned to the lead used in ammunition; much to the ire of many shooting and even some hunting organizations. After studies linking lead to the death of waterfowl, lead was prohibited in the hunting of aquatic birds over twenty years ago. More recently, studies have indicated that in addition to bioaccumulation in game, hunters, too, may be ingesting and accumulating unhealthy levels of lead due to fragmenting lead bullets. Interestingly — and surprisingly — researchers have found that lead particles can travel up to 18 inches away from the original wound channel, embedding into the meat almost invisibly. Other researchers have found higher levels of lead in hunters and their families as compared to non-hunters.
In response to these and other studies focused on lead’s possibility to harm land-living animal species, California has led the push for across the board lead-bullet bans, and has even implemented legislation to ban lead in hunting ammunition by 2019. In my opinion it’s only a matter of time before other states follow suit, with possible regulation emanating from the national level (i.e., the EPA). While those opposed to lead-bullet bans have many reasons for their opposition — some of them good some of them quite bad — I think they are fighting a losing battle. Whether or not lead-bans are being used as a backdoor way to further regulate hunting and shooting, the proven toxicity of lead means that other substances are eventually going to take its place.
Choosing the right substances, however, is tricky business.
Across the board, regulation in the United States is typically reactive. Was there a horrific accident at that four-way intersection that everyone already knew was unsafe? Perhaps we should add a stop light. Was our town dramatically unprepared for that massive flood? Let’s carry out policies — that we’ve long known we should — to better prepare us for the next one. Have millions of smokers died from lung cancer? Maybe we should make tobacco less appealing to youngsters. The list goes on. And on. Precaution is often thrown to the wind; if we don’t know that something is bad, let’s not worry about it until there’s lots of evidence showing that it is, in fact, bad.
Many regulations related to exposure to chemical substances follow the same basic process, tossing aside the precautionary principle. Let’s use substance X until its negative effects on humans or wildlife are undeniable… then let’s ban it in favor of another as-of-yet-untested substance Y.
I highlight this regulation process only to note that now leaded ammunition is in the limelight. We’ve used it for centuries, reaping lead’s benefits along with its health and environmental costs. As these apparent costs have mounted, scientists have taken interest. After many decades and many studies, the science shows that, indeed, lead is toxic. In response to the science, regulators are responding by trying to eliminate the lead, in favor of replacement materials with — in some cases — as-of-yet-unknown health and environmental consequences. If, decades later, these materials turn out to be harmful too, another new substance will be chosen and the cycle will continue.
But I’m a guy who doesn’t like to serve as an unwitting guinea pig. I also want to minimize the impact my hunting has on the ecosystems that produce my food. I imagine a lot of people out there, especially hunters and environmental conservationists, share these ideals. So to decrease the chance that I’ll find out — twenty years down the line — that the non-lead ammo I had used was actually toxic for me or the environment, I decided to look into the various options for non-lead hunting bullets and shot, their performance as ballistic projectiles, and what’s known about their toxicity. Below I detail some of the pros and cons of each material, as well as what I was able to uncover about any likely toxicity. Of important note, basically all the likely lead replacement metals have known toxicity, so it’s really a situation of ‘pick the least bad option’. Spoiler alert: for the most part the better projectile materials have more troubling toxicity and vice versa.2
Lead is on its way out due to proven toxicity. It’s really too bad that lead is toxic, because it’s otherwise clearly the best option for bullet material. Lead is a dense, malleable metal, both of which are good properties for bullet making. Dense materials, for a given amount of volume, carry greater momentum to the target and as a result have better penetration ability. Lead’s softness is also a good quality, as it is easy on gun and shotgun barrels, allowing them to live longer lives. Furthermore, lead is a relatively less expensive metal, compared to some of the below options, making target practice cheaper. Cheaper target practice can translate into more target practice, which can in turn translate into more ethical kills.
So lead loses on the toxicity dimension but is strong on all other dimensions. How do the other options measure up? In the rest of this post I discuss copper, steel, tungsten, bismuth, and tin with regard to their toxicity, environmental safety, and ballistic performance.
Copper is my favorite replacement for lead. For our big game ammunition, we are currently using copper bullets from Barnes. I like copper because of it’s excellent penetrating ability because the material doesn’t fragment much, and for its somewhat lower (known) risk of toxicity. The copper bullets we use perform admirably in Robyn’s 25-06 rifle, with sub 1-inch groups at 100 yards.
But, copper is unfortunately more expensive than lead, meaning it is notably more costly to target practice with. It’s also a bit harder than lead, and is associated with problems of ‘copper fouling’ in rifle barrels. And unfortunately to my knowledge no manufacturer makes full-copper rimfire bullets, and I’ve never come across copper shotgun pellets (a shotshell full of copper would be ridiculously expensive). The reason no rimfire bullets are made from solid copper is likely because copper is less malleable than lead. It would likely expand very little, even in hollow point format, making it less lethal to small game. It’s also probably a function of cost: hunters are willing to pay a premium for their big game bullets since they will use few of them, but hunters tend to burn through rimfire ammunition much more quickly. These facts mean we’re left with poorer options for our Ruger 10/22, which we most often use for jackrabbit hunting.3
While it seems that copper is likely safer than lead and some of the other materials detailed below, it’s still not fully risk-free. The truth is that no metal seems to be safe when ingested into animal or human bodies in excessive quantities (having micro amounts of copper, iron, etc. is normal and important for biological functioning).4 This leads to a pretty clear rule of thumb: avoid eating your bullets or pieces of your bullets, regardless of what they’re made out of. This rule is easier to abide by when you’re using copper, as it doesn’t tend to fragment as much as lead upon impact.
That said, copper toxicity appears to be only a moderate concern for humans; if you tend to chew your game meat you’ll probably find any chunks of copper that would be large enough to be concerning. Doses in humans of up to 10mg per day for two months didn’t show any significantly negative clinical effects. To put this in perspective, a 100 grain bullet is 6479mg. So to eat 10mg/day would be to eat only .0015% of a bullet each day. Because copper bullets tend to stay together even after they hit their target, any ingested fragments would probably be quite small indeed. However, the science isn’t fully settled on this, and very long-term exposure to elevated copper levels has been associated with degenerative disease, like Alzheimer’s, and has the potential to be associated with cancer.5
Many other studies conducted on copper toxicity have been performed on smaller animals like rats. In these animals excess consumption of copper is linked to many negative health effects, including liver damage. It’s probably not much of a stretch to think that if copper ingestion causes toxicity in some small animals, it may cause similar toxicity in other animals. As a result, copper seems imperfect in the environmental friendliness department. If animals are killed with copper bullets, and the bullet’s wound path is trimmed by hunters and left in the field, animals who consume that left over meat may ingest harmful quantities of copper. This is basically the same process that has raised concern about lead in upland game hunting. Quite possibly the saving grace of copper is that, unlike many lead bullets, it tends not to fragment; the bullets will remain larger and as a result less likely to be ingested inadvertently by other animals. If possible, it’s probably a good idea to retrieve any copper bullets that are embedded in your kill and pack them out with you.
Steel is my next favorite choice in alternative bullet and shot materials. Like copper, steel has excellent penetrating ability in centerfire rifle calibers. In fact, it’s penetrating qualities are so good that it can actually be a detriment to hunters: some steel core ammunition, particularly in smaller calibers, is classed as ‘armor-piercing’ and is not eligible for civilian use. Steel is even less dense than copper though, so to make a similar weight bullet, the steel bullet would need to take up more volume in the firing chamber. This is problematic, because a larger bullet displaces gun powder, meaning that the energy of the projectile necessarily decreases (when confined to a fixed firing chamber size). In other words, all-steel bullets would be at a ballistic disadvantage to both copper and lead.
Even worse, steel is harder than both copper and lead, and tends to be very resistant to deformation, making an all-steel bullet less ideal for harvesting game. (The mushrooming of a bullet imparts more of its kinetic energy into the target. If bullets don’t mushroom they’ll often just pass right through, doing less damage). This hardness also makes steel tend to wear down shotgun barrels more quickly than softer metals, yet another drawback. And finally one last problem: there is concern that steel bullets may have a greater propensity to spark when they hit rocks, making them more likely to start wildfires than other (non-magnetic) bullet materials.6
So steel is less good of a projectile than either copper or lead. But in its favor, steel is cheaper than lead and way cheaper than copper. It’s also notably less toxic than lead, though like copper, excess iron (a main ingredient in steel) has been associated with certain health risks such as the production of free radicals and possibly cancer. You still don’t want to be eating chunks of steel (unless you’re Michel Lotito). Steel’s lower cost, coupled with its lower health and environmental risks leave it as my preferred choice for shotgun shot (for reasons further described below) and second-best choice for rifle ammunition.
The idea for this article was spurred by my research into shotguns. Trying to get jackrabbits with my bow hasn’t been working too well. And while Robyn’s 10/22 rifle can easily take down small game, it’s not the best fit for denser, brush-filled territory. In my reading about non-lead shotgun ammunition, I had narrowed in on tungsten as the ideal replacement for lead. It’s even denser than lead, giving it very nice ballistic properties. A slight drawback is that tungsten is very hard, so like steel it can damage shotgun barrels. It’s also more expensive than lead, but it’s definitely the standout leader in the ballistics category for non-lead shot. I was sold.
Then I researched its toxicity.
Tungsten might be the best example of non-adherence to the precautionary principle of all the lead substitute materials. At the time of its widespread introduction as a munition, scientists knew very little about its potential toxicity. Most scientists assumed tungsten was a relatively biologically inert metal, though hardly any studies had been conducted to confirm this. Because there weren’t dramatic or clear known negative effects of tungsten, little fuss was made about its use as a lead substitute. There are many variations of tungsten used in shotgun shot and it’s increasingly popular in that application. Sometimes tungsten is mixed with iron, sometimes with nickel, sometimes with nylon or some other plastic. But since the introduction of tungsten as the best performing replacement for lead shot, there have been a few high-profile instances of possible tungsten toxicity in the environment and in humans. Tungsten is still widely used today in the munitions industry, but from what I’ve read, it seems like this might be another lead-like mistake.
Tungsten has recently been shown to be toxic to soil microorganisms and insects like earth worms. Where tungsten was once thought to remain inert in soils, it’s now clear that it doesn’t. Tungsten actually acidifies the soil, making it inhospitable for certain organisms. A healthy soil microbiome is critical for plant growth, which is critical to plant-eating animals — the kind that we hunters like to eat. If our tungsten ammunition leads to significant loss of plant life, loss of animal populations will follow suit. Furthermore, when tungsten is exposed to the atmosphere or to water it releases various active — and quite possibly toxic — compounds. Tungsten-related compounds can then find their way into plants and insects and possibly into the animals that eat them. Concerns about the potential link between tungsten and cancer have also been raised.
Because shotgun shot, by its very nature, tends to disperse in the animal killed and into the environment, and because I don’t savor the thought of bio-active tungsten compounds leaching into my hare stew, I am going to avoid using tungsten shot. I just think it’s too risky at this point. The science on the toxicity and health effects of tungsten is unsettled, but pointing in a negative direction for the safety of the material. Unfortunately, this decision relegates me to using ballistically inferior steel shot for my jackrabbit hunting.
Bismuth is an interesting lead-alternative. It is more dense than steel and copper and as a result has better ballistic performance as shotgun shot. However, bismuth is a relatively brittle metal, and this lack of malleability makes it inappropriate for use in big game (expanding) bullets. It’s main use is as a replacement for leaded shotgun pellets. Unlike steel, bismuth’s brittleness allows it to be less damaging to shotgun barrels, making it more appropriate for use in older, non-hardened barrels. It’s also cheaper than tungsten, another nice benefit. And it’s definitely less toxic than lead and likely less toxic than tungsten. In fact, a bismuth compound is the active ingredient in the popular stomach-aid Pepto-Bismol. However, as much as I’d like to use bismuth as my primary pellet material, I don’t think it’s the wisest choice.
The reason that I’m shying away from bismuth is directly due to its brittleness. When an animal is shot with bismuth pellets, many of those pellets can actually shatter within the animal as they strike bone, making them very difficult to remove. This wouldn’t be a concern if bismuth were completely non-toxic, but it isn’t. Long-term ingestion of bismuth has been shown to lead to some pretty nasty health issues. Unfortunately, research on the toxicology of bismuth seems to be still in its infancy, perhaps, like tungsten, due to possibly incorrect assumptions about its relative biological inertness. It does seem to be — from the limited evidence available — pretty benign in small doses on rare occasions. But my plan is to continue to eat game meat in moderate doses on frequent occasions. If I can’t eliminate the bismuth pellets from my meat because they’ve effectively dissolved into it, that could be a problem over the long run. I’m going to stick with steel, again based on the precautionary principle.
I should start out the tin section by noting that the tin 22LR bullets I’ve shot (from Winchester) fly with the same accuracy that my darts do when I’m drunk. They’re terribly inconsistent. I pretty much hate these bullets. Robyn’s Ruger 10/22 rifle can easily put 5 shots in a two-inch circle at 100 yards with good lead ammunition, but we’re lucky to get them in a ten-inch circle at 100 yards with the tin ammo. Unfortunately, Winchester’s tin bullets are one of only non-lead bullet options for rimfire small game rifles like the 10/22. (The other option is a bullet from CCI that claims to be, to an unspecified degree ‘accurate out to 50 yards’… not exactly a confidence inspiring sales pitch.)
So, I’ve already had bad experience with tin bullets’ ballistic performance — and this experience is a direct result of the material itself. Tin is light, even less dense than steel. It’s also pretty hard; our tin bullets have a tough time doing much expansion at all. Ballistically, tin sucks.
But, on the upside, tin is probably the safest of all the metal’s I’ve listed. Tin is still considered a great material for food storage containers and we’ve used it for ages. That said, like any metal, ingesting excess amounts of tin can produce toxic effects, so don’t go eating your tin bullets. I know they look delicious, but try to exercise some restraint.
Ultimately, I think that the poor performance of tin will trump it’s relatively low toxicity — we probably won’t see too many projectiles made from tin in the future. Based on my personal experience, that’s a good thing.
No Magic Bullet
It would be really nice if lead weren’t toxic. If it weren’t, it’d be the proverbial magic bullet. But as the above sections have demonstrated, there really doesn’t seem to be any magic bullet. The better ballistic performers (like tungsten) tend to be more risky to the environment and human health. The materials proven to be more safe, like steel and copper, have definite drawbacks as compared to lead. Life is full of tradeoffs, I guess. I’m not willing to trade my health or environmental integrity for ballistic performance so I’ve chosen to use copper for my rifle bullets (not much of a loss, really) and steel for my shotgun shot. If manufacturers would start making decent rimfire non-lead hunting bullets, they’d certainly have my business.
So to repeat a couple of key points: 1) make sure to discard any ‘bloodshot’ areas of the meat you’ve harvested to try to remove all metal fragments as it’s not good to eat any metal in large quantities and 2) choose your bullets wisely, thinking about your health and the environment.
Finally — and vitally importantly — the fact that the materials used in bullets, even the best ones, may have certain environmental or health risks does not mean that hunters shouldn’t hunt, or that hunting bullets should be banned altogether. Most other options for procuring one’s meat are almost certainly worse for health and the environment than the release of a bullet. It’s important to keep being environmentally friendly in a broader perspective. I just try to take steps to protect my health and reduce my impact when I can. Hunting for wild food is never going to be a risk-free activity, but its risks are ones I’ll gladly bear.
Note: I’m not an expert in toxicology. I’m also not a metallurgist. My findings are based on my own research and understanding of the literature. So, interpret the above findings with the knowledge that I may have missed something. If anyone has any more experience with these issues, please feel free to post it up in the comments or contact us via the contact page!
- That is, unless you want to be like Emperor Nero. ↩
- Here is a list of approved shotgun shot materials. ↩
- An additional threat to the use of copper ammunition is that some solid copper (as opposed to copper hollowpoint) bullets may be classified as armor piercing rounds, meaning that regular civilians are unable to buy them. ↩
- “Redox active metals like iron (Fe), copper (Cu), chromium (Cr), cobalt (Co) and other metals undergo redox cycling reactions and have the ability to produce reactive radicals”; reactive radicals are a concern for their carcinogenic properties. ↩
- [One of the most damaging ROS occurring in biological systems is the hydroxyl radical formed via the decomposition of hydrogen peroxide catalyzed by traces of iron, copper and other metals (the Fenton reaction). The hydroxyl radical is known to react with the DNA molecule, forming 8-OH-Guanine adduct, which is a good biomarker of oxidative stress of an organism and a potential biomarker of carcinogenesis. This review discusses the role of iron and copper in uncontrolled formation of ROS leading to various human diseases such as cancer, cardiovascular disease, and neurological disorders (Alzheimer’s disease and Parkinson’s disease).] ↩
- As an interesting aside that I’ve not heard much mention of… the most common non-lead shot material is steel, but I’ve never come across restrictions or concerns about steel shot and the potential for wildfire. Given that a shotgun shell fires commonly over 100 times more projectiles in a single shot, I’d think that the risk of wildfire would be greater than just a steel core bullet. ↩