What Is TMJ Ammo? And How Does It Differ From Other Ammo? The Full Guide!

There are many different types of ammunition in the rifle and pistol world. Still, they all have one thing in common: A bullet, which serves as their projectile. The bullets we fire from handguns and rifles trace their history to the development of the 15th-century matchlock arquebus. A long gun, the arquebus fired cast lead balls, and today’s bullets serve the same purpose, and most are also made of lead. It’s because of lead, though, that we should take a few minutes to answer the question: “What is TMJ ammo?”

Short Answer – What Is TMJ Ammo

Unlike FMJ ammo, Total Metal Jacket (TMJ) ammo surrounds a lead bullet’s exposed base with copper, helping prevent any lead exposure when we handle it. The less lead we’re exposed to, the better it is for our health. Excessive lead levels in our blood can cause a range of neurological and other serious health problems, for one.

FMJ Ammo

Almost every gun owner or war movie fan has heard the term “full metal jacket” or “FMJ” when applied to ammunition. FMJ ammo is simply a bullet, commonly made of lead. It’s almost completely covered over with copper or another metal (copper is best), though. However, standard FMJ bullets also usually have a small amount of exposed lead at their base, which presents a downside, and here’s why:

While lead is soft, making it ideal for use as a bullet, there’s no doubt it presents a potential health hazard if you’re over-exposed to it. As an example, remember that during the last several years, the media has been full of reports of lead exposure in older water pipes. Plus, we’ve known for decades that chips from old lead-based paint pose potential harm to children or anyone else that ingests them. This lead issue is why TMJ ammo was developed.

Telling Them Apart

Technically speaking, I have to admit that a TMJ bullet is also a full metal jacket bullet. However, a quick look at your ammunition’s cartridge will tell you if it’s FMJ or TMJ. With an FMJ bullet, you’ll see visible lead at its base while you won’t see any on TMJ.

Shooting TMJ and FMJ

When it comes to accuracy and velocity in target shooting, TMJ ammo is just as effective as FMJ. I have found no difference between the two types of ammunition on the range.

TMJ Ammo Pros

There are a number of pros to TMJ bullets, including:

  • TMJ is excellent for target shooting.
  • Big game hunters often use TMJ ammo because it penetrates deeply.
  • Lower potential risk of exposure to lead is a plus.

TMJ Ammo Cons

All ammunition is a tradeoff among different characteristics, and TMJ is no different, so there are several downsides:

  • Like FMJ, TMJ doesn’t expand upon impact.
  • With no expansion ability, stopping power or “knockdown” capability in a TMJ bullet may be less than with a hollow point. This could be important in self-defense situations.
  • While TMJ is effective for big game, it’s usually not recommended when hunting standard game.
  • TMJ is costlier than FMJ ammo, which is relatively inexpensive.

Why Appreciate It?

TMJ ammo’s health benefits are the main reasons I appreciate it, mainly because I spend a lot of time at indoor ranges. For instance, in any given period at a busy indoor range, many bullets or rounds are being fired, often simultaneously. That much “lead in the air,” so to speak, may create actual lead in the air or an appreciable amount of lead particles which could lead to potentially harmful air pollution.

Also, if the range isn’t consistently cleaned, those lead particles could end up on the ground and then on your shoes, hands, face, and even in your mouth. Fortunately, the vast majority of indoor ranges pay close attention to cleanliness, including air filtration and regular facility cleanup.

Should I Use It?

Now that we all can answer the question, “What is TMJ ammo?” the only thing left to consider is whether we should go with it or not. Personally, because I shoot more often in indoor ranges than outdoors when training with my handgun, I go with TMJ. I don’t worry about TMJ-versus-FMJ, though, when I’m at an outdoor range because the air disperses any lead particles so much it’s not a concern. Lastly, you should always thoroughly research TMJ like any other ammo type before putting it in your firearm.

Leave a Comment