Understanding the various types of ammunition and the purposes of each is part of being a well-rounded shooter. Of course, it can be a little intimidating the first time you walk into a gun store and see row after row of ammunition for sale, all sporting different labels. What’s the difference between full metal jacket and hollow-points? Are frangibles as bad as people say? Consider this your primer on the basics of ammo selection — Ammo 101, if you will.
Before We Begin on Ammunition
A round of ammo has multiple parts, including the case, primer, powder and bullet. A complete round is not a bullet. The bullet is the projectile seated in the top of the case and the part that we will be covering today. We aren’t going to get into grains, powders or variations in loads and brands — just bullet basics.
Full Metal Jacket Ammo (FMJ)
Full metal jacket bullets are, at their simplest, meant for range use. These bullets typically have a lead core covered in a harder metal jacket. They do not expand on impact but simply punch right through the target. Because of that, they are not suitable for self-defense use but are great for training. They are more affordable than defense rounds as well.
Total metal jacket (TMJ) and complete metal jacket (CMJ) bullets are almost identical to full metal jacket bullets. Rather than having a metal jacket encasing only the top and sides of the bullet, total metal jacket bullets have a jacket that extends to cover the base of the bullet as well. You might find your local range prefers or requires total metal jacket rounds to reduce air pollution. When you have that many rounds fired in an enclosed space on a regular basis, every little bit can help.
Again, these bullets are not designed for self-defense use. Keep your full metal jacket, total metal jacket and complete metal jackets at the range. Save yourself some money while training, but keep your carry gun or home-defense gun loaded with something else.
Hollow-point bullets are designed with a hollowed-out space over the nose of the bullet. That feature sets them apart from target rounds, such as the aforementioned full metal jacket bullets, which have a solid, round nose to penetrate straight through targets. When a hollow-point impacts an object with sufficient mass, the opening over the nose helps it expand (mushroom). Hollow-point variations perform at different levels of expansion and varied weight retention. When selecting a self-defense round, take the time to do your research to be sure it delivers a solid performance.
Also of note is the fact that all hollow-points are not jacketed. (You’ll notice the jacketed hollow-point, or JHP, designation on some ammo.) Some, such as those manufactured by Sinterfire, Inc., do not have jackets and are instead frangibles, which we’ll discuss next. Others, like Hornady FTX, contain a polymer insert in the hollowed-out nose of the bullet. The insert aims to prevent material from clogging the bullet and impeding expansion while also driving itself back into the bullet, improving expansion.
There are quite a few types of hollow-points, including jacketed hollow-points, semi-jacketed hollow-points and hollow-points. Once you understand the basics of how these bullets function, the names make more sense. Hollow-points are made to create large, permanent wound cavities while simultaneously slowing to prevent over-penetration, making them your go-to round for self-defense.
But remember, all ammo is not created equal. Just because a round has a hollow-point bullet does not mean it is automatically a capable, reliable self-defense round. Be sure to train with your chosen self-defense rounds. Different guns handle various ammo differently, and the recoil and accuracy of a defensive round varies from that of a range round. You need to get accustomed to it. As always, training is key.
Frangible bullets get a bad rap thanks to a tidal wave of misinformation in the gun industry. These are not the frangible bullets of decades ago; these are bullets created using up-to-date knowledge and technology. They are far better than the old designs.
These bullets have aged quite well. Frangibles were first made for mid-twentieth-century shooting galleries. You’ll find Remington’s Spatter-Less and Winchester’s SpatterProof labeled as gallery cartridges in the 1967 version of Shooter’s Bible. Fortunately for us, the manufacturing process has changed since 1967.
Today they’re great for self-defense and hunting applications. But the concept remains the same: Reduce the risk of ricochets and backsplash. Those gallery rounds were manufactured from iron powder. Unfortunately, they tended to over-penetrate and were also magnetic.
Today, manufacturers use powder metallurgy, which is the process of pressing and sintering finely powdered metals into objects. Copper is the predominant metal used because it is highly malleable and ductile. Frangibles aren’t made entirely from copper though; metals like tin are used as binding agents.
The flexibility of the bullets makes them ideal for steel-plate and close-range shooting, but that’s not all. Frangibles work for self-defense. The fact that they drastically reduce risk of over-penetration is a stellar bonus.
One of the frontrunners of the frangible world is Sinterfire, Inc., founded in 1998 for the purpose of designing and manufacturing lead-free frangible ammunition. The company’s bullets are used by rather a lot of government and law-enforcement agencies. Features include controlled frangibility, reduced hazard risk, no ricochet, decreased bore wear and reduced chamber pressure. The bullets are manufactured without jacketing, plating or surface treatments and are designed to deliver superior accuracy.
Do you have to use frangibles in your carry gun? Of course not, but they are an option. Hopefully, with time, a greater understanding of frangibles will spread through the industry and they’ll see wider-spread use.
Bottom Line on Ammunition
There are other types of ammo out there, such as jacketed soft points, flat-nosed bullets, bonded bullets and polymer-tipped bullets. The deeper you get into the world of shooting, the more types of rounds you’ll see. For use in self-defense though, focus on the three mentioned here. Remember, full metal jacket rounds are for the range, hollow-points are for self-defense, and frangibles can be used for both. Variations and nuances abound, but the basics remain the same. Take the time to test-fire your gun with a variety of ammunition before selecting one for daily carry use.
About Kat Ainsworth
Outdoor writer Kat Ainsworth has been carrying concealed for 15 years and hunting for more than 20 years. She writes for a variety of industry publications, covering hunting, ballistics and self-defense, though she has a background in K9 Search-and-Rescue and emergency veterinary medicine. Kat calls Marshfield, Wisconsin, home, but she enjoys traveling as part of her gun-related lifestyle. She has yet to find a firearm she didn’t want to fire.