[ED: Here’s an old Ask Foghorn post that addresses a question we get frequently.]
Reader Randall writes:
While I’m not exactly a newbie when it comes to *using* firearms, I am a newbie gun *owner*. And now that I’m in the position of purchasing ammo, I’m finding things to be rather confusing when sorting out all there is to be had.
I think I’ve kind of figured out what I want to buy for my Springfield XD 9mm, but choosing ammo for my AR-15 is proving to be more daunting.
How ’bout an article for us newbie-types explaining the differences between, say, “full metal jacket” versus “total metal jacket” versus “jacketed hollow point” versus “jacketed hollow point subsonic” versus “frangible” versus “full metal jacket boat tail” versus “soft point” versus “boat tail hollow point” versus “lead round nose” versus “safety slug” versus…you get my drift.
That’s a pretty wide-ranging question, so I’ll answer it in three parts. Part one is all about the different types of projectiles and there are quite a few. But first, in order to explain the different designations, a little about how bullets are made.
A few weeks back, I took a trip to the Hornady manufacturing plant in Grand Island, Nebraska. It’s a good read in itself and I recommend you take a look, but this picture is the one we really want to focus on.
The vast majority of bullets are constructed of a solid lead core with a copper covering (called a “jacket”) that contains the lead. Lead is used because it’s an extremely dense, yet cheap metal, making it perfect for giving projectiles their weight while keeping the overall size small. Copper is used because it’s strong enough to keep the softer lead from de-forming, but soft enough to allow the gun’s rifling to “grip” the bullet.
The copper jacket starts out as a cup, having been cut from a long sheet. Through a process called “drawing,” the cup is lengthened and shaped to fit the profile of the projectile they’re making. These cups will eventually end up as jackets for 5.56 NATO rounds.
However, while this process is very efficient, it’s extremely difficult to actually get the metal to encase the entire lead core without any gaps. To keep production costs down, bullet manufacturers usually leave one end of the projectile open. Which end is open – and how that’s done – determines the classification of the projectile.
Here are three 150 grain .308 caliber bullets (a “grain” is a unit of bullet weight). And while they look very similar, the way in which they were manufactured is very different. The first projectile on the left is a “full metal jacket” (FMJ) round with a solid copper point. The other two are an open tip and a soft point bullet respectively, with openings in the copper at the tips of the projectiles.
Looking at the bases of the bullets we can see why they’re different. The “full metal jacket” bullet actually has an opening, but it’s at the bottom of the round. So what makes these bullets different? Let’s go over each one.
Full Metal Jacket (FMJ)
“Full Metal Jacket” or “FMJ” projectiles usually aren’t actually fully jacketed, but simply have a copper jacket covering the top of the projectile. Military FMJ ammunition is completely covered by a copper jacket (as per the Hague Conventions), which uses a more involved process than traditional civilian ammunition (but doesn’t alter the lethality of the rounds at all).
FMJ ammunition is manufactured so that the bottom of the original cup of copper becomes the tip of the bullet, producing a continuous jacket of copper over the top of the round. However, most civilian ammunition leaves the base of the lead core uncovered, as illustrated with the bullet on the left in the above images (the ones with the three bullets side by side).
FMJ ammunition is cheap to produce, and therefore is the traditional choice for use on the firing range. The uniform and aerodynamic design of the projectile also makes it the ideal choice for long range precision shooting.
However, that streamlined design means that it’s also more likely to penetrate a living target (like a human or an animal) and keep going out the other side, possibly injuring people further downrange and leaving only a small wound in the target. Therefore, for home defense and hunting it’s not advisable to use FMJ ammunition.
There are a couple variations of FMJ ammunition that can be recognized by their designations:
- Round Nose (RN) — The tip of the bullet is rounded in a spherical shape, which is not particularly aerodynamic. This is used mostly in handgun ammunition and older rifle ammunition.
- Boat Tail (BT) — The rear of the bullet is tapered to give it a more aerodynamic profile (the two bullets on the left in the images above). This is common in “match” grade rifle ammunition and long range target ammo.
FMJ ammo is the “default” ammunition style, and the only one where the jacket is drawn from the tip. Every other projectile uses a jacket that is drawn from the base, and the tip is usually designed to perform some sort of function.
Open Tip (OTM)
Again, with FMJ rifle rounds, the bottom of the cup becomes the tip of the bullet. With “open tip” bullets, the opposite is true — the bottom of the cup is the bottom of the bullet. While this covers more of the lead core than the FMJ projectile, it leaves a small opening at the tip of the bullet where the jacket was drawn together. Many people mistake this for hollow point ammunition, but the point is too small to work that way.
Open tip bullets are preferred by long distance shooters as the manufacturing process is more consistent than with FMJ projectiles. That leads to higher quality bullets and better performance at long distances. These projectiles are often referred to as “OTM” or “open tip match” to indicate that they’re held to a higher standard than regular range ammunition.
Due to the construction of the projectiles, open tip bullets perform nearly identically to FMJ projectiles when they strike the target.
Hollow Point (HP)
For self-defense or hunting, hollow point bullets are the way to go. Following the same general manufacturing process as the “open tip” bullets, these projectiles feature an exaggerated opening at the front of the bullet. The idea is that this opening will force the projectile to expand upon impact with a target, dumping all of the energy of that round and creating a bigger wound with more “stopping power.”
However, that gaping hole in the front of the bullet in self-defense rounds also creates an immense amount of drag as it travels through the air and negatively impacts its long range capabilities.
Gun control advocates have successfully branded hollow point self-defense rounds as “cop killer” bullets in some states and have implemented legislation banning their use. Some believe they are “armor piercing” but as we have tested and proven, that’s not the case.
Hollow point ammo is the favorite choice for police officers and those who carry a concealed weapon for one simple reason: when a JHP round hits something, it stops. They don’t keep going like FMJ rounds can, potentially injuring people on the other side of the target.
Soft Point (SP)
While hollow point ammunition is great for handgun rounds at close range, when you’re hunting at longer ranges with a rifle you need a round with better ballistic properties. One of the first attempts to make a projectile with the accuracy of a FMJ bullet and the “terminal ballistics” (how well it does when it hits a target) of a hollow point round was the “soft point” bullet.
The main difference between a soft point bullet and an open tip bullet is that with the soft point, some of the lead core protrudes from the front of the round. This gives the bullet a more aerodynamic shape than the open tip bullets, and also has a tendency to flatten the projectile when it hits a target. The bullets don’t open up as dramatically as a hollow point round, but it’s still an improvement. Especially where hollow point rounds are illegal.
But if you’re looking for a type of bullet that’s a really good hunting round, there’s something far better out there than a soft point bullet.
How do you get the benefits of a hollow point with the long range accuracy of a FMJ? By adding a small piece of plastic. “Ballistic tip” bullets feature an exaggerated opening in the tip of the copper jacket to allow the bullet to expand upon impact. But that hole is covered by a cone-shaped piece of plastic that allows the bullet to perform as if it were a FMJ. It’s a pretty nifty design, and one that I use to great effect in my hunting ammunition.
Other Bullet Types
While a lead core is the standard for bullet construction, there are some other interesting designs that are purpose-built for specific roles. Here are a few:
- Frangible — These bullets are made out of compressed granules of copper, and are designed to shatter upon impact with a hard surface. They are used mainly as training ammunition in shoot houses, where over-penetration is a serious concern.
- Standard Copper — Copper-only bullets are extremely effective and they’re available in a variety of bullet types and weights. Eliminating the lead core keeps more lead out of the environment and some states have mandated their use for hunting.
- Total Metal Jacket (TMJ) — Lead core bullets that are totally encased in copper to reduce lead exposure. Some indoor ranges require this as it reduces the amount of lead particles in the air.
- Jacketed Flat Nose — A jacketed bullet usually used in lever-action rifles
- Steel Core / Armor Piercing — The lead core is replaced with a solid dart-shaped chunk of steel, designed to pierce body armor and some thinner-skinned vehicles. This can ruin steel targets, and cause ricochet hazards if used improperly.
- Tracer — Bullets are treated with a chemical (usually phosphorus) that burns as the round flies downrange. This allows shooters to see where their bullet flies, but also keeps burning after the projectile lands and can be a fire hazard.
That’s a good introduction to the different types of rifle bullets and why they’re used. If you’d like more information on this or other firearms topics, let us know.