Quick answer: Full metal jacket (FMJ) is a bullet with a soft lead core fully encased in a harder metal jacket, usually copper. That jacket keeps the bullet from deforming, so an FMJ holds its shape and does not expand when it hits a target. A hollow point (JHP) is built to do the opposite: it expands, or "mushrooms," on impact. That difference is the whole story. FMJ is the affordable, clean-shooting choice for training and range time. Hollow points are the standard choice for personal defense because they transfer more energy and are less likely to over-penetrate.
If you have ever stood at the ammo counter wondering why two boxes of the same caliber cost different amounts and say different things on the label, this is the guide for you. The two terms you will see most are full metal jacket and hollow point. They are not interchangeable, and picking the right one is mostly about what you are doing that day: practicing, or carrying for defense. Fusion builds 1911 and double-stack pistols, so we care a lot about what feeds and fires reliably. Here is the plain-English version.
What does full metal jacket mean?
A full metal jacket bullet is a soft lead core wrapped in a harder metal shell, almost always copper. The lead gives the bullet its weight. The jacket gives it a tougher outer surface so the bullet keeps its shape, fouls the barrel less, and feeds smoothly. Because the lead is sealed inside the jacket, an FMJ does not expand on impact. It punches a clean hole and keeps going. That is exactly what you want for paper targets and steel, and it is why FMJ is the everyday range round.
Why shooters use FMJ
FMJ earns its place for a few simple reasons:
- It is the most affordable common ammo, so it is the round you shoot the most of.
- The jacket means less lead fouling in the barrel and easier cleanup.
- It feeds reliably, which matters for high-volume practice.
- It produces consistent, predictable point of impact for working on fundamentals.
- It is accepted at virtually every range, because it shoots clean.
What is a hollow point (JHP)?
A jacketed hollow point has a hollow cavity in the nose. When it hits a soft target, that cavity makes the bullet expand and flatten out, often into a mushroom shape. Two things happen as a result: the bullet transfers more of its energy into the target, and it is far less likely to pass all the way through and keep traveling. That is why hollow points are the standard defensive round. They are built to stop, not to punch through. One trade-off to know: hollow points can perform less consistently after passing through heavy barriers like clothing or glass, so defenders choose a quality load and confirm it runs in their pistol.
| How they compare | Full Metal Jacket (FMJ) | Hollow Point (JHP) |
|---|---|---|
| Construction | Lead core fully encased in a copper jacket | Lead core with a jacket and an open hollow nose |
| Behavior on impact | Holds its shape, does not expand, penetrates deep | Expands or mushrooms, transfers energy, less over-penetration |
| Best use | Training, range time, practice, plinking | Personal defense and carry |
| Cost | Lower; the round you practice with most | Higher; bought in smaller quantities |
| Barrel fouling | Low, the jacket shoots clean | Low, also jacketed |
| Over-penetration risk | Higher, can pass through a target | Lower, designed to stop in the target |
FMJ vs hollow point at a glance. On a phone, swipe the table sideways to see every column.
FMJ vs hollow point: which should you use?
Match the round to the job:
- Training and range days: FMJ. It is cheaper, it shoots clean, and you can run a lot of it.
- Personal defense and carry: hollow point. It expands, transfers energy, and reduces the risk of over-penetration.
- Building familiarity with a carry gun: practice with FMJ to save money, then confirm your pistol feeds your chosen defensive hollow point reliably before you trust it.
Is FMJ good for self-defense?
It is not the first choice. FMJ does not expand, so it tends to over-penetrate, which means it can pass through a target and keep going. For defense, a quality hollow point is the standard because it expands, dumps more energy into the target, and is less likely to travel beyond it. Use FMJ to train and to make sure your gun runs, then carry a defensive hollow point you have verified feeds in your pistol. One historical footnote people often ask about: expanding bullets are restricted in international warfare by long-standing convention, which is why militaries train and fight with FMJ. That rule is about armies, not about your defensive ammo choice at home.
What this means for your pistol
The round only matters if your pistol feeds it cleanly, every time. That is where build quality shows up. Fusion's 1911 pistols are built and fitted to feed reliably, and the XP Pro, our double-stack 9mm that runs Glock magazines, is designed for high-volume shooting. Whatever you carry, the rule is the same: practice with FMJ, confirm your gun runs your chosen hollow point, and then carry with confidence. For a deeper look at the rounds themselves, see our complete guide to 9mm ammo types.
Frequently asked questions about FMJ and hollow point ammo
What does full metal jacket mean?
It means the bullet's soft lead core is fully encased in a harder metal jacket, usually copper. The jacket keeps the bullet from expanding, so it holds its shape on impact and fouls the barrel less.
What is the difference between FMJ and hollow point?
FMJ does not expand and penetrates deep, which makes it ideal for training. A hollow point expands on impact, transfers more energy, and is less likely to over-penetrate, which makes it the standard defensive round.
Is FMJ good for self-defense?
It is not the first choice because it does not expand and can over-penetrate. A quality hollow point is the standard for defense. Use FMJ for practice, and carry a verified hollow point.
Why is FMJ cheaper than hollow point?
FMJ is simpler to manufacture and is made in huge volume for practice and training, so it costs less. Hollow points are a defensive product made in smaller quantities, so they cost more.
Does FMJ damage your barrel?
No more than other jacketed ammo. The copper jacket actually reduces lead fouling compared to bare lead bullets, which keeps the barrel cleaner.
Can you hunt with FMJ?
It is generally a poor hunting choice because it does not expand, which can mean cleaner pass-through wounds and less effective stops. Expanding ammunition is preferred for most game, and many areas have rules on this, so check your local regulations.
