Bullets have come a long way from the cup and core designs that dominated the 20th century. Nowadays, there are a plethora of cup and core, bonded, and all-copper bullets on the market. Monolithics have become a popular choice amongst hunters and perform very differently from traditional lead core designs. For those considering monolithics, this article will shed some light on the strengths and weaknesses of all-copper projectiles in a hunting context.
All-Copper Bullet Experience
To provide some background, I have hunted with all-copper projectiles for a number of years. However, my experience is limited to Barnes TSX, TTSX, and Hornady CX bullets. There are some copper bullets such as those from Hammer that are designed to shed their petals creating some fragmentation. I have no first hand experience with those and as such will not speak to them in this article.
Strengths
First of all, the largest strength of copper bullets is their incredible penetration. This is due to the fact that they typically retain very near 100 percent of their weight while travelling through and animal. This is well documented both from anecdotal evidence as well as ballistic gel testing. A good example of this is a follow-up shot I had on a big boar who was heading for a swamp. This 225gr Barnes TTSX entered the boars back ham and was recovered against the base of the skull during skinning. This was over 5 feet of penetration, and it retained 95 percent of it’s weight.
For those interested, Vortex Optics has a number of cartridge comparison videos where they shoot both lead and copper projectiles into ballistics gel on their Youtube channel. I’ve linked one such video below for interested viewers.
Another benefit of all-copper projectiles is their legality. Several states including California as well as some European countries no longer allow lead core bullets for hunting. By choosing a monolithic projectile you avoid needing to research if your particular hunting location allows your bullet of choice. Finally, using all-copper projectiles can alleviate potential concerns around lead contamination in the harvested meat.
Weaknesses
On the other hand, monolithic projectiles are not without drawbacks. One significant one is reduced BC’s compared to a lead core projectile of the same weight. Recently, new designs such as the Hornady CX and Barnes LRX have greatly increased the efficiency of all-copper bullets. However, due to the density of the material they are still unable to match the most efficient lead core projectiles. Couple that with the necessity to add grooves on the shank of the bullet to alleviate pressure issues and all-copper bullets are simply less efficient than their lead counterparts.
Another weakness of copper bullets is that they require higher impact velocities to expand. This is only an issue on long range shots or with particularly slow cartridges. However, as long range shooting progresses some hunters will find that a copper projectile limits their effective range.
In my experience the wound channels from copper bullets decrease dramatically when impact velocity nears 2400 fps. The most impressive results have come from cartridge bullet combinations that are pushing the bullets north of 3000fps at the muzzle. Hunters would benefit from selecting lighter projectiles for caliber when using monolithics. For example, the 120gr Hornady CX is an excellent bullet for the 6.5s and I have had great success with the 130gr 30 caliber Barnes TTSX.
Thirdly, monolithic projectiles tend to have smaller wound channels than their lead core competitors. This is exacerbated in moderate velocity cartridges. It is simple physics, if the wound channel is longer than a bullet of the same weight from the same cartridge, it will also be narrower.
Applications
Given the strengths and drawbacks, there are situations where monolithic projectiles excel and others where lead core options are better. Perhaps the best use case for monolithic projectiles are on large game such as moose or bison when hunting in thick cover. These animals are enormous and hunting cover often results in opportunities with less than ideal shot angles. Copper projectiles will be able to shoot through a shoulder and still exit the other side on steeply quartering shots. Additionally, in this style of hunting the reduced ballistic coefficients aren’t a factor as shot distances are short.
Where copper projectiles are less than ideal is on more medium sized game. For deer sized animals, the penetration of the copper projectiles is unnecessary. Virtually any lead core bullet from almost any hunting cartridge achieves adequate penetration and a wide wound channel on medium game. That said, they will work on deer if regulations or health concerns require you to use a monolithic projectile.
Closing Thoughts
In closing, copper projectiles provide outstanding penetration at the cost of wound channel diameter and ballistic efficiency. The key question is whether or not your application requires the extra penetration. When selecting an all copper bullet, pick a light for caliber bullet as velocity greatly improves performance penetration will still be exceptional. As more and more locals move to banning lead projectiles, all copper bullets are certain to be here to stay.