In the First Part, we learned about how bullet weight, length, diameter, and velocity have many different impacts on shooting and the effects of what you shoot. Although this section will look at things in different terms, a lot of what was covered in the first section will be applicable or talked about here. For instance, we will talk about penetration vs expansion, fragmentation, tumbling and yaw, energy transfer, and other similar concepts. We’ll start with some common bullet types.
FMJ and TMJ
Full Metal Jacket (FMJ) and Total Metal Jacket (TMJ) bullets are commonly available loads typically used for target shooting or plinking. The construction of an FMJ bullet typically consists of a soft inner core (commonly lead) surrounded by a tougher jacket material (usually a type of copper). Originally, these were designed because the soft lead used in bullet designs would deform inside the working mechanism of a firearm, causing feeding issues. Harder metal jackets keep the bullet from deforming for more reliable feeding. The jackets can also allow the bullet to reach higher muzzle velocities and prevent lead buildup in the bore and working mechanisms of the firearm – a bullet with a Total Metal Jacket even more so.
While FMJ bullets still have an exposed lead base (seated inside of the case), TMJ bullets have no exposed base and are therefore completely jacketed. TMJ bullets are less common than standard FMJ, and tend to be used in niche applications where the smallest amount of lead exposure possible is desirable.
FMJ bullets tend to be relatively inexpensive in the calibers they’re commonly used in, such as centerfire handgun and military rifle cartridges. FMJ ammo, typically inexpensive and mass produced, will tend to be less accurate in general terms. It’s well-suited for general shooting where the highest degree of accuracy is less important than being able to shoot for a lower price.
Full Metal Jacket ammunition, in general, is not designed to expand. They will penetrate deeper than expanding bullet designs, but will not create wide wound channels. Some FMJ ammo is designed to tumble or yaw, meaning the bullet will travel end over end or sideways when it hits its target, creating a bigger wound channel without expanding. However, these wound channels are generally less consistent than bullets which are designed to expand.
In many states the use of non-expanding full metal jacket or military ammunition is expressly forbidden for game hunting and its use is typically looked down upon in sport hunting communities even where it is legal.
That said, FMJ bullets are used in a couple of hunting applications. Hog hunters sometimes use them, especially in lighter calibers like .223/5.56, because they are more likely to get the effective penetration needed for the tough anatomy of a hog. They’re also often used in small game hunting where a smaller hole is preferable to preserve the meat and hide of a small animal.
Hollow Points
Hollow Point ammunition is exactly what the name implies – a bullet with a hollow tip or point.
In general, the open tip construction of a hollow point is designed to allow soft tissue to flow into the cavity, slowing the bullet and expanding the petals. This expansion may allow the bullet to become as large as twice its original size. This creates an impressive wound cavity but also sacrifices penetration. Rapid expansion and low penetration is something that has to be considered with the use of a hollow point, but is often considered a feature.
Usually used in handguns, expanding hollow points have two main uses: hunting and self-defense.
In defensive handguns, relatively low penetration is required as the gun may need to be discharged in a densely populated area with only one valid target. The rapid expansion creates a higher chance of an immediately disabling effect. The low penetration serves to keep the bullet from completely penetrating through the target, reducing the chance of collateral damage and transferring all of its energy that might be lost otherwise on a pass through.
Hollow points are also used in handguns for hunting – typically (though not always) in larger cartridges such as the 10mm Auto, .357 Magnum, .45 Colt etc. They are popular with hog hunters who hunt in close quarters and may need to stop a large and aggressive animal charging at them, but may also be used for deer and similarly sized game.
Some hollow points may also go through a process called bonding.
Bonded hollow points have the lead core fused to the outer jacket of the bullet. This process allows the lead to remain attached to the copper jacket, resulting in less separation. A non-bonded bullet may expand and separate more violently, even breaking up into multiple pieces and losing much of its weight. A bonded hollow point will have a much higher weight retention and remain largely in one piece.
Although the overall expansion of the bullet will be diminished, the higher weight retention and solid composure of the bullet are desirable in certain circumstances. They may be favored for defensive firearms, where a bullet would be expected to perform after passing an intermediate barrier. For hunting purposes, a bonded hollow point that keeps the bullet intact is beneficial for ensuring proper penetration of and complete wound track on large game animals.
One criticism of hollow points in certain scenario is that they’re designed to open up only on the fluid resistance that they meet when hitting a soft target. If a hollow point bullet passes through another type of material – commonly somewhat softer materials like heavy denim, leather or plywood – the tip of the bullet may get clogged with that material and fail to expand. This is something more of a problem in defensive firearms than ones considered for hunting uses, but it’s a problem that other bullet designs have sought to address. We’ll talk about some of these bullet designs later.
Not all hollow point bullets are designed to expand. Some are created as a result of the manufacturing process of the bullet. Others are created with a hollow point for purposes affecting accuracy. For example, the Sierra Match King is a hollow point boat tail (HPBT) bullet that is well renowned for its accuracy. The hollow point on this bullet is not designed to aid in the expansion or terminal performance of the round, but as a result of the manufacturing process that makes the bullet accurate.
Another example is the Hornady Action Pistol (HAP) bullet, a competition bullet designed for accuracy, reliable feeding, and performance in competitions. From Hornady’s website:
“Expansion isn’t an issue in action pistol shooting, so we removed the expansion-aiding features like the skives and cannelure. The result is a bullet that delivers the accuracy its sleek appearance promises.”
Soft Point Bullets
Soft point bullets are similar in goal to hollow point bullets. They consist generally of a lead core with a metal jacket until the point, which is left exposed. This exposed tip is called a soft point because the lead is a softer metal than the jacket, so it expands much more easily upon encountering fluid resistance. Although soft point bullets are expand to design, their expansion is generally slower than a modern hollow point bullet. Because of this, they will also tend to have higher penetration than a similar hollow point.
Soft point bullets have an advantage over hollow points in that they mimic the natural shape of full metal jacket bullets. Many firearm designs, especially older military firearms and pistols, are designed for the round or flat nose of a full metal jacket bullet. This may cause feeding malfunctions when trying to use modern hollow points in these older firearms, which often feed a semi-jacketed or soft point bullet much better.
Soft point bullets are also commonly used in lever action firearms. Because of their design, lever action firearms store ammunition front to back in the feeding tube. Under the recoil of the rifle, the primer at the rear of one loaded cartridge may contact the pointed front of the bullet behind it, setting off the round in the tube. This is an obviously unsafe condition, so a bullet with a flatter lead point was a sensible solution.
Soft point bullets can be easily found for a variety of firearms, and are often a cheaper expanding alternative to the more expensive hunting ammunition on the market. Although technological advances have created bullets that could be said to surpass them in some ways, soft point bullets are still trusted by many to take game.
Ballistic Tip Bullets
Tipped bullets are a relatively newer invention seeking to capitalize on the best attributes of both hollow points and full metal jackets. The polymer tipped bullet is constructed of a lead core and a heavily jacketed base, like a lot of other bullets. Unlike others, the ballistic tipped bullet has a cutaway at the nose where a pointed tip is inserted. This tip is very commonly a polymer plastic, but occasionally other materials (such as aluminium) are used.
The ballistic tip gives the bullet a very similar profile to FMJ ammunition, resulting in reliable feeding even in semi-automatic firearms where lead tipped and hollow point ammunition can cause problems. Ballistic tip ammunition is also very aerodynamically stable and accurate.
When ballistic tip bullets hit a soft target, the plastic tip will push back into the core of the bullet, causing it to expand. Expansion in ballistic tip bullets is generally very consistent and reliable. One odd behavior of ballistic tip ammunition is its tendency to expand so violently at close ranges that they make fragment into multiple pieces. At close ranges, this can mean very rapid expansion and wide wound channel, causing massive damage to relatively light targets. This effect does sacrifice penetration at close range, causing relatively shallow wound tracts that may not fully reach vital organs and may have little to no exit damage. At longer distances, as bullet velocity is reduced, they will mushroom more uniformly like a hollow point and tend to stay more intact.
Lighter, faster bullets have less inertia and are more vulnerable to this type of destabilization and fragmentation effect. For this reason, light.
Cast Lead Bullets
The original bullet for many centuries, cast lead bullets are still around in force for a number of uses. Lead bullets are generally cheaper than jacketed ammunition. They can be made at home with the proper casting and melting equipment, and are favored among reloaders who want to lower the cost of loading their own ammo.
Most lead bullets, despite their names, are not pure lead. They are often an alloy containing other such metals as antimony and tin. Pure lead is a very soft metal, and will easily wear or deform. Attaining the proper hardness is important for a lot of reasons. Lead bullets, because of their softness, can be cast so that they fit the rifling of the barrel very well for better accuracy. A bullet that’s too soft, however, will leave particles behind in the barrel when it begins moving too fast. This process, called leading, will leave lead particles in the barrel which may clog up the rifling in the barrel and lead to loss of accuracy. A bullet that is harder will be less likely to lead the barrel.
Because of this process of leading, cast lead bullets are not well suited for use in gas operated semi automatics, such as the AR-15, M14, or many other rifles on the market. The leading can plug up the gas port and other working mechanisms of the gun, causing malfunctions and extra headache during cleaning. They are commonly used in a variety of handguns and manually operated rifles, being particularly known for their use in revolvers and lever-action rifles.
Lead bullets are known to fall somewhere in between full metal jacket bullets and other expanding bullet types in performance. The softness of the lead allows it to open up when hitting a soft target, but the solid construction allows the bullet to remain together and penetrate deeply. Hard cast flat nose bullets out of rifles are considered very powerful hunting rounds, and are usually cast in large-bore, heavy weight bullets.
A notable variation of cast ammunition is the wadcutter.
Wadcutter ammunition has a flat, square nose as opposed to the rounded or sloped nose of other ammunition. The wadcutter was originally designed for competition shooting, where the flat nose was intended to cut perfect holes in paper to help scoring. The wadcutter has also been adapted to the semi-wadcutter, a design halfway between a wadcutter and a traditional round nose bullet. The semi-wadcutter has enjoyed an interesting history as a hunting, target, and self defense round. Made from cast lead or alloy, the solid construction of the semi-wadcutter bullet created effective penetration and expansion. The FBI has been known to use a 158 grain semi-wadcutter hollow point loaded to +P pressures in their revolvers. The bullet was widely used because it created reliable expansion out of even short-barreled revolvers, where traditional hollow point loads at the time struggled to reliably expand.
Copper Bullets
Lead Free Bullets are a relatively new feature to the ammunition market, producing some surprising results. In some areas, a lead free bullet is legally required for hunting because of environmental considerations. There are not many materials available which are effective as projectiles, cheap enough to shoot, and soft enough to shoot out of a steel barrel without issue. Copper fits all of these criteria well, and companies have recently started making monolithic copper bullets for hunting and even for other uses such as self defense and security.
These copper bullets, typically turned out in large numbers on a CNC lathe, are capable of being produced to very high standards. This means a high degree of control and repeatability in shooting and terminal performance. In particular, copper bullets are usually designed to expand very well and stay intact. Copper bullets from companies such as Barnes are known to cause very efficient wound channels by expanding reliably and staying intact. An important factor in copper bullets is weight retention.
Weight retention is a measure of how much of the bullet remains intact, measured by comparing the weight of the bullet with the weight of the mass recovered from a target. Weight retention is important because of its implications of what the bullet is doing within the target. A bullet that retains more of its weight is a bullet that will maintain a consistent wound track that stays wide throughout its depth. A bullet with low weight retention will fragment quickly, even violently, resulting in a very wide and shallow wound. This is sometimes desirable for smaller game (as we’ll see with other bullet types), but copper bullets have become a favorite among hunters for big or dangerous game, where thorough penetration and efficient damage are prized for a quick kill.
Even among fracturing bullets, the high control of the CNC manufacturing process is allowing advancement. Several companies are producing lightweight copper bullets designed specifically to fracture rapidly. Other fragmenting bullet designs such as polymer tipped varmint rounds are somewhat unpredictable, expanding or fragmenting differently at different velocities and distances. A polymer tipped round may flatten or expand at one range while it fragments into many small pieces at a closer range. Companies such as Lehigh Defense, Liberty Ammunition, and G2 now produce copper ammunition designed to fragment in a controlled manner.
A common method of doing this is machining solid copper stock into a bullet with a solid base and “petals” made with many cuts. The design of these bullets allows the petals to separate from the base, creating a very wide initial channel while the base will continue penetrating more deeply. Although there’s a lot of debate about the effectiveness of these high-speed designs, the precision manufacturing does allow them to consistently separate the way they were designed to.
Frangible and Composite Core Bullets
Frangible bullets are those which are designed to come apart on impact and separate into many fine pieces. Frangible ammo is typically designed for safe shooting at steel targets, where high powered rifle rounds may ricochet off of steel targets with dangerous energy left. The frangible bullet is designed to strike a hard target and nearly disintegrating, leaving little or no large section which can reflect off of the target.
Live fire training involving close engagement with steel targets is where frangible bullets are most commonly used, and many high end training schools require the use of frangible ammunition. The video below demonstrates the safety of frangible ammo on steel targets even at close range.
Because of the loosely constructed nature of frangible ammunition, it tends to create wound tracts that are shallow but very disruptive along their short length. The bullets rapidly expand and fragment, causing many small particles to spread in a very wide area. This can create devastating effects on relatively shallow targets, but is unsuitable for uses where significant penetration is required. YouTube user John Carr shows the effects on a relatively small deer in the video below. (WARNING: Graphic content)
https://www.youtube.com/watch?v=A19RZY5AgMA
In some situations, this rapid fragmentation and shallow penetration is actually desired for a job. One popular use is among varmint hunters who want to quickly kill a small animal while doing as little damage as possible to the hide. In response, Barnes has created a bullet appropriately named the “Varmint Grenade”. The Varmint Grenade is a copper bullet with a copper-tin composite core and a hollow nose. The lightweight bullets are designed to be fired at a very high speed out of cartridges like the .223 and .22-250. The combination of high speed, low mass, and composite core create a bullet that expands and dumps its energy so rapidly that they may not even exit a small animal such as a prairie dog. When the bullet does manage to exit, it will almost certainly not be in one piece. This effect creates massive internal organ damage and minimal hide damage.
This has been a guide to general effects of some of the most common bullet types one might run into when shopping for ammo. There are always exceptions to the way certain things perform, and there are too many bullet types to hope to be able to cover them all. With a basic knowledge of the common bullet types available on the market, hopefully you will have the information you need to make the proper selection for your needs.
