I have been giving the issue of non-lead bullet performance a lot of thought lately, since a lot of my hunting is in California where the ban on lead bullets will be near absolute in the early 2020’s. I had and still have a lot of questions. Do they perform as well on game animals? What are the trade-offs? What do I need to know in making my decisions? I hope that this article will give you some guidance and food for thought on these questions.
Sectional Density and Penetration
I started with sectional density (“SD”). Let us start with the basics. Instead of recreating the wheel, I will quote Chuck Hawks on the subject. “SD is the numerical result of a calculation that compares a bullet’s weight to its diameter. To calculate a bullet’s sectional density divide the bullet’s weight (in pounds) by its diameter (in inches), squared. The higher the SD number the better the SD and the heavier a bullet is in proportion to its diameter. SD stays the same for all bullets of the same weight in the same caliber; shape does not affect SD. SD is important because it has a significant effect on penetration. Other things being equal (like impact velocity, bullet design and material, etc.) the higher the SD number, the better the bullet’s penetration. In other words, a skinny bullet of a given weight tends to penetrate better than a fat bullet of the same weight, because it concentrates the same force on a smaller area of the target. For example, if other factors are equal, a 150 grain .270 bullet will penetrate better than a 150 grain .35 caliber bullet. Penetration is important because the bullet must get well inside an animal to disrupt the functioning of its vital organs. A bullet that fails to penetrate the fur, skin, muscle and bone necessary to reach the vital organs is very unlikely to bring an animal down.”
With this in mind, however, it soon became clear that while the SD calculation remains the same for lead and non-lead bullets, the traditional notions of what SD is needed for which type of game (see, for example, http://www.chuckhawks.com/sd.htm) do not translate directly to non-lead projectiles. Specifically, while SD of lead/non-lead bullets will be the same for given weight and caliber, the fact that, to achieve that same weight the non-lead bullet had to be longer and made of material that is harder/less malleable than lead, means they will perform differently at impact. Further, as discussed below in the Accuracy section, the non-lead bullet choice generally may be lighter than normal and have higher velocity. Thus, Chuck’s “other things being equal” is thrown off because all things are not likely to be equal.
These variations led me to start looking at what the performance differences were. Chuck Hawks notes the positive and negative of the lead versus non-lead bullets as follows: “All of these [non-lead] bullets create relatively long and narrow wound tracks and usually shoot right through the animal on broadside heart/lung shots, wasting a good bit of their energy and killing power on the scenery beyond.” While on the positive side, he notes that “copper is not as heavy as lead, a copper bullet of equal weight in a given caliber is longer than a lead core bullet,” which means that “for the deep penetration required to reach the vitals of the most heavily built animals, premium bullets like… Barnes TSX (and similar homogeneous bullets).. come into their own. These bullets are excellent for use on large and heavy animals worldwide.”
Another article pointed out that, in broadside shots, the pass through of non-lead bullets is more predictable leaving better (more frequent) blood trails if the shot did not kill immediately. On the other hand, as noted by Chuck Hawks, a pass through means that energy was unnecessarily expended on the rock/tree on the other side of the animal.
I found a scientific study that backed these pros/cons up. (http://www.sciencedirect.com/science/article/pii/S0048969712013848). While this study was clearly intended to give support to the ‘ban lead” movement, its findings are consistent with Chuck Hawks, and others’, observations of the performance of non-lead v lead of the same weight and size. To sum it up, if you compare the same caliber and same weight bullets, the non-lead bullet is likely to have greater penetration and more likely have an exit, while having an initially narrower wound channel.
An interesting note is that the scientific study indicated that the wound channel of the non-lead bullets was not statistically significantly different than the wound channel from lead bullets at 5 and 10 cm, respectively. (e.g., from the chart it appears that their data indicates about 5-7 mm difference in the initial size of the wound channel). While, from a statistical perspective this may not rise to the level of “significant,” I have my doubts that this difference is not significant in the real world. On a live animal, 5 mm (.197 inches) of tissue damage over a distance of 5 cm (1.97 inches) seems pretty significant to me. Admittedly, this first 1.97 inches of less expansion is occurring in the outer meat/bone before the vitals are reached. On the other hand, in a bad shot situation, this may matter. Thus, I think their data actually supports the conclusions above – that the non-lead bullet takes a little longer to reach full expansion, but penetrates deeper. This may be to your disadvantage in a broad side shot where you waste energy on the rock behind the deer. On the other hand, this characteristic may be to your advantage in a quartering away shot situation where the bullet has to travel through more of the animal before it reaches the vitals (e.g., a shot where penetration is important).
One further, non-scientific (but interesting) point. I found a few Youtube videos of ballistic gel tests comparing various lead to non-lead bullets. The results were the same as discussed above – deeper penetration for non-lead bullets, though none of them measured wound channel at various distances after impact.
To make this very simple, BC is the measure of air drag. The BC of the non-lead and lead (same caliber and same weight) seems to be about the same or, there is a slight advantage for non-lead hunting bullets. Below is an example of the data I found.
BC of .270 caliber 130 gr Bullets (Non-Lead on the Left):
.460 Hornady GMX .460 Hornady Interbond
.459 Nosler E-tip .416 Nosler Partition
.465 Peregrine Plainsmaster .433 Nosler Silvertip
.392 Barnes TTSX .436 Sierra Gameking
.450 Scirocco II
I found the same pattern for .308 and 6.5 mm. My conclusion is that that BC between the two types of bullets are roughly equal.
I will save you from reading the rest of this paragraph and give you the conclusion up front. From a big picture perspective, it depends on if your gun likes them. It is very clear that the production and design of non-lead bullets rivals that of lead bullets and can produce, in hunting rounds, equally accurate rounds.
With the spoiler out of the way, the details are actually quite interesting. The folks at Cutting Edge Bullets, summed up this issue pretty well when they noted that a longer bullet of the same weight may require a faster twist to stabilize it. “Thus, the use of lighter bullets requires ‘thinking faster’ instead of heavier. A lighter bullet with a high ballistic coefficient shot at faster speeds has less drop at all ranges than heavy jacketed bullets. Energy is slightly less and wind drift is virtually the same.” From what I could find this is the best summation of all of the comments and evidence that I found.
The pro/cons are pretty fairly stated by Cutting Edge Bullets, with some interesting side effects. I can use a lighter non-lead bullet (if pushed a bit faster and with the right twist rate) to achieve the similar bullet flight results as a heavier lead bullet, with less bullet drop. Peregrine bullets, a manufacturer of non-lead bullets, seems to agree and argues the superiority of their non-lead bullets based on the premise that you can go lighter with higher velocity and reduced recoil. I personally experienced this trade-off of pros/cons. I used a 165 gr, .308 non-lead bullet, on two large Russian brown bears and had great results. I have had similar results with the same round on elk. All animals were dead on the spot. I found another writer that experienced this with Nosler’s E-Tip on Australian buffalo (lighter non-lead bullet, pushed a bit faster that its heavier lead counter-part would have been traveling) and the bullet shattered bone and exited on the off side of these very tough animals. Traditional wisdom would dictate a bullet of 220 gr or more for brown bears or buffalo. The non-lead bullet required me to make sure that I had the correct twist and that I used more powder to push the speed up (with the obvious downsides on barrel life, etc.), but the terminal performance speaks for itself. It is true that you lose energy and sacrifice some performance in the wind by using the lighter bullet, but gain less drop and higher speed. Clearly, what your intended purpose will affect your choice. On the other hand, if you are hunting a non-lead area where you do not have the choice, you need to understand the trade you are making and how it applies to the animal(s) you are hunting.
Long Distance Performance
Most of the factors relevant to long range hunting I have already discussed above. BC, wind drift and accuracy, among them. The primary remaining issue is expansion and performance at long distance (e.g., lower speed). I was not able to locate any studies (scientific or otherwise) on the subject. The manufacturers of non-lead bullets all claim that with the designs they have implemented (pedals, nose cones that initiate expansion, longer depth of the nose cavity, etc.), their non-lead products all compare equally with their leaded counterparts. At this point, I have no way to verify these claims. The only study which, tangentially, touched on this issue was the study that was meant to help advance the ban on lead ammo. This study found that there was no statistically significant variation between the wound channels for animals shot with lead and non-lead bullets at ranges of 50-150 meters (55-164 yards) when measured at 0, 5 and 10 cm into the animal. The implication of this data is that, at short ranges, the non-lead expanded at the same rate at their lead brothers. Thus, the argument goes, the same techniques that achieved this result should also succeed at longer distances and slower speeds. This, to me, is counter-intuitive and needs more study. Particularly, since it seems to directly contradict the conclusion and evidence that non-lead bullets achieve greater penetration. If the penetration data and opinions are true, it seems hard to reconcile that with the same bullets also opening up at the same early rate. I simply do not know the answer to this, though my gut says that the initial would channel will be less for the long and fast non-lead bullets, expanding to the same after 5 cm or so. The fact that they do not expand as fast for the initial impact and first 5 cm or so, gives them the greater penetration. Again, I admit, I am speculating at this point. What does this mean for long distance, probably the same result, it will take non-lead bullets longer to expand at the greater distance and slower speed, but at those slower speeds they will penetrate further. You will have to decide which is more important to you if you engage in long range hunting.
Does The Lead Get Into the Meat You Eat
I am not going to get to deep into this, given the fact that much of the data out there is influenced by the goals of those publishing the data/studies. I simply do not think there is much objective data available. As a result, I will only note a few things. My experiences using non-lead bullets over the last couple of year match the various manufactures’ claims that the non-lead bullets retain more of their weight. For example, Hornady GMX claims to retain 95% of its weight (my results have exceeded this for the few that I recovered). While Hornady does not claim any specific weight retention for its Interlock bullets and 90% for Interbond bullets. You will see similar claims by the other makers. This makes sense to me since non-lead bullets are monolithic. However, from a big picture perspective, the lead bullets also shed very little weight. Let’s be specific here. For the 130 grain Interbond the loss will be no more than 13 grains (.03 oz). Further, not all of that will be the lead core. Such amount of lead loss is further reduced when the hunter cleans the animal and cuts out the damaged portions (though some of the lead may travel as very tiny fragments outside of the visible wound area). In fact, one of the studies I found on this issue has some very good pictures which show you where most of the lead ends up – right along the wound channel. http://huntingwithnonlead.org/PDFs_Main/WI%20DNR%20Copper%20Bullet%20Study.pdf
Lastly, any remaining lead will likely not be consumed by the same person and in one sitting. If you consume your game animals like I do mine, it is cut up and eaten periodically and by all of the members of my family, extended family and friends. Thus, the amount of lead consumed by a single person by using lead bullets is miniscule. Thus, if you do not want any lead in your meat, then the choice is clear. On the other hand, I am convinced that lead shot animal flesh is safe to consume.
While not directly related to lead in your meat, the fouling in your rifle tends to be less with the non-lead bullets. This is because of the use of the harder metal in non-lead bullets. This may or may not be a significant factor for you, but is worth adding to the pros column.
Putting this all together, it seems to me that this becomes a matter of knowing your gun, picking the right ammo for the job and shot placement. The biggest trade-off, which I can verify, is the greater penetration in exchange for delayed full expansion. Which is better is clearly a personal decision and could be argued both ways endlessly. However, for those hunting in a jurisdiction that prohibits lead bullets, understanding the characteristics of the non-lead bullets is important. I think that, boiled down to its essence, the lesson is to think lighter and, therefore, faster, for your choice in deciding on the appropriate non-lead bullet.